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1. Isolated Type II SLAP Tears Undergo Reoperation More Frequently
DeFazio MW, Özkan S, Wagner ER, Warner JJP, Chen NC. Knee Surg Sports Traumatol Arthrosc. 2021 Jan 2
Query Letter to the Editor
A.J.R. Leenen, PT, MScNorman E. D’hondt, PT, MScMichel P.J. van den Bekerom, MD, PhD
We have read the paper “Isolated type II SLAP tears undergo reoperation more frequently” by DeFazio, M. W., Özkan, S.,et al. published in Knee Surgery, Sports Traumatology, Arthroscopy(2021) with great interest.
We appreciated the authors’ effort to identify risk factors associated with type II superior labrum anterior to posterior (SLAP)repair and reoperation after SLAP repair. However, we have some concerns about the interpretation of the study outcomes and the clinical implications based on how a type II SLAP (re)tear had been established. We therefore encourage the readers to consider the study outcome in light of the following remarks.
1.Interpretation of study outcomes. Based on their multivariable logistic regression model, the authors conclude that “surgeons and patients should take the factors smoking, knotless suture anchors, and having an isolated SLAP repair into account to lower the possibility of unplanned reoperations”. However, the presented model-fits expressed in pseudo-R-squared values for 1) the unplanned reoperation model (0.029), and 2) the failed SLAP repair model (0.074) are very low. Therefore, the outcomes of this model must be interpreted with caution. Besides, only associations between the previous factors and a SLAPII repair failure were established, rather than cause-effect relationship. Thus, although these factors might be of some predictive value for SLAP-II repair failure, they have to be subjected to further investigation (e.g. a prospective controlled study design) to provide clinicians and patients with such significant recommendations.
2.Establishment of type II SLAP (re)tear. We are aware that diagnosing a symptomatic SLAP-lesions can be challenging In general, diagnostic 28modalities used to establish suspicion of a SLAP-lesion vary from 1) history taking , to 2) positive clinical provocative SLAP-lesion tests [6,7], 3) SLAP-lesions ruled in by negative results of provocative clinical tests to determine other pathologies than SLAP-tears , and4) confirmation by an MR arthrogram .However, these diagnostic modalities do not fully confirm the presence of a SLAP tear, nor do they indicate if the SLAP tear is symptomatic or asymptomatic. For example, a type II SLAP-lesion might even be noticed by accident diagnosed during an arthroscopy addressing other pathologies than a SLAP-lesion [2, 4]. Nevertheless, although diagnostic uncertainty is inevitable, the authors do not provide the readers with any information on1) the modalities used to establish a symptomatic SLAP-lesion diagnosis, and 2) criteria to determine whether or not the initial SLAPII repair was indicated. Furthermore, by defining a SLAPII repair failure as “a reoperation that addressed pathology to the biceps and labral complex to include revision SLAP repair or a biceps tenodesis or tenotomy procedure” ,only the curative procedures are addressed, rather than the reasons to perform a second surgical procedure. Lack of such information leaves the readers uncertain about the specific population to which the assumed risk factors apply and hampers clinical decision making.
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- Bhatnagar A, Bhonsle S, Mehta S (2016) Correlation between MRI and Arthroscopy in Diagnosis of Shoulder Pathology. J Clin Diagnostic Res 10:RC18-21
- DeFazio MW, Özkan S, Wagner ER, Warner JJP, Chen NC (2021) Isolated type II SLAP tears undergo reoperation more frequently. Knee Surg Sports Traumatology Arthrosc 1–9
- Dougherty MC, Kulenkamp JE, Boyajian H, Koh JL, Lee MJ, Shi LL (2019) Not All SLAPs Are Created Equal: A Comparison of Patients with Planned and Incidental SLAP Repair Procedures. Adv Orthop 2019:1–6
- Familiari F, Huri G, Simonetta R, McFarland EG (2019) SLAP lesions: current controversies. Efort Open Rev 4:25–32
- Hegedus EJ, Goode A, Campbell S, Morin A, Tamaddoni M, Moorman CT, Cook C (2008) Physical examination tests of the shoulder: a systematic review with meta-analysis of individual tests. Brit J Sport Med 42:80
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Response from authors:
Thank you for your thoughtful comments and your interest regarding our paper. We agree that the definition of retear is difficult to establish. We chose re operation as a metric because it is an unambiguous event that can be well defined. It is important to recognize that we are describing what was done by surgeons and studying these events. We are not trying to establish when a re tear occurs. Again, thank you for your interest in our study.
2. Anterior cruciate ligament reconstruction with the use of adductor canal block can achieve similar pain control as femoral nerve block
Min, H., Ouyang, Y. & Chen, G. Knee Surg Sports Traumatol Arthrosc 28, 2675–2686 (2020)
Query Letter to the Editor
Dongdong Yu, Li Jiang, Xiaoyu Wang, Jianli Li
Anterior cruciate ligament reconstruction (ACLR) is widely accepted as the treatment of first choice for individuals with unstable function due to ligament deficiency. In order to complete this procedure safely and maintain high patient satisfaction, adequate postoperative pain control must be provided. Inadequate early pain management may hinder mobilization and recovery, and ultimately may affect patient satisfaction and long-term outcomes. To alleviate this problem, multimodal analgesia, such as nonsteroidal anti-inflammatory drugs, periarticular anesthetic injections, opioids, and peripheral nerve blocks, have been used to manage postoperative pain . However, the challenge of pain control after ACLR is to provide adequate analgesia while maintaining motor function.
Femoral nerve block (FNB) is known as the gold standard to reduce opiate consumption and decrease postoperative pain scores in ACLR . Unfortunately, it tends to result in motor blockade of the quadriceps muscle and potentially delay postoperative mobilization, as well as increase the risk of falls. Recently, adductor canal block (ACB) has emerged as an alternative to FNB, with the advantage of sparing the motor nerve supply to most of the quadriceps muscle and may lead to a reduction in falls after surgery [2, 5].
With great interest, we read the article by Min et al published in August, 2020 in the Knee Surg Sports Traumatol Arthrosc. The authors performed a meta-analysis and concluded that ACB is recommended as an attractive alternative to FNB as the peripheral nerve block of choice for ACLR . At the outset, we would like to congratulate the authors for writing an informative article with novelty. Nevertheless, we have several suggestions and queries that we would like to communicate with the authors.
Firstly, four electronic databases (PubMed, EMBASE, Cochrane Library, and SCOPUS databases) were systematically searched by the authors. It would make the outcomes more convincing by obtaining more literature if the authors searched other databases, like BIOSIS previews, clinicaltrials.gov, and NLM Gateway. Secondly, the manual search protocols should also be included in this meta-analysis. Essential literature will be ignored if the manual search protocol is incomplete, and unpublished data such as gray literature should be included. Thirdly, why did the authors use the standardised mean difference as summary statistic rather than mean difference for continuous outcomes? Could the authors give a reasonable explanation? Fourthly, the authors used an inverse variance (IV) random effects model to pool the data in this review. In our opinion, studies should be combined by using the DerSimonian and Laird random effects model, which considers both within- and between-study variations. Fifthly, for the ten outcomes addressed in this current review, while they can sometimes be necessary, can make the review unfocused, unmanageable for users, and are prone to selective outcome reporting bias. The Cochrane Handbook for Systematic Reviews, recommend no more than seven outcomes. Thus, it would be better to select only core or critical sets of outcomes of most relevance to the review question, and to form a “summary of findings” table or other summary versions. Finally, different types of anaesthesia may compromise the reliability of meta-analysis; as a result, the researchers should carry out subgroup analysis or sensitivity analysis based on the above-mentioned risk factors.
We respectfully appreciate that Min et al provided us with an important meta-analysis which can provide a guide for clinical decision-making. However, more studies with large sample size and good scientific design should be carried out to clarify this issue. We would welcome some comments by the authors as this would help to further support the findings of this important clinical trial.
- Borys M, Domagała M, Wencław K, Jarczyńska-Domagała J, Czuczwar M (2019) Continuous femoral nerve block is more effective than continuous adductor canal block for treating pain after total knee arthroplasty: A randomized, double-blind, controlled trial. Medicine (Baltimore) 98(39):e17358.
- Edwards MD, Bethea JP, Hunnicutt JL, Slone HS, Woolf SK (2020) Effect of Adductor Canal Block Versus Femoral Nerve Block on Quadriceps Strength, Function, and Postoperative Pain After Anterior Cruciate Ligament Reconstruction: A Systematic Review of Level 1 Studies. Am J Sports Med 48(9):2305-2313.
- Li D, Alqwbani M, Wang Q, Yang Z, Liao R, Kang P (2020) Ultrasound-guided adductor canal block combined with lateral femoral cutaneous nerve block for post-operative analgesia following total knee arthroplasty: a prospective, double-blind, randomized controlled study. Int Orthop.
- Min H, Ouyang Y, Chen G (2020) Anterior cruciate ligament reconstruction with the use of adductor canal block can achieve similar pain control as femoral nerve block. Knee Surg Sports Traumatol Arthrosc 28(8):2675-2686.
- Zhang Z, Wang Y, Liu Y (2019) Effectiveness of continuous adductor canal block versus continuous femoral nerve block in patients with total knee arthroplasty: A PRISMA guided systematic review and meta-analysis. Medicine (Baltimore) 98(48):e18056.
Response from the authors:
We appreciate the comments by Yu et al. regarding our article entitled “Anterior cruciate ligament reconstruction with the use of adductor canal block can achieve similar pain control as femoral nerve block” published in 2020 in the Knee Surg Sports Traumatol Arthrosc . Some flaws in our article initiated this discussion.
We acknowledge that we only searched four electronic databases in the literature search. Additional searches of other databases, including BIOSIS Preview, ClinicalTrials.gov, and the NLM Gateway, were not able to find any new articles. Furthermore, the reference lists of the included studies were also checked for additional studies that were not identified with the database search. In the results section, we used the standardised mean difference as summary statistic rather than mean difference for continuous outcomes. Effect sizes expressed as standardised mean differences are a useful method to compare the effect of an intervention across studies when different measures (such as pain scores) are used.
In our study, sensitivity analysis was used to explain the heterogeneity among the included studies. Among the outcomes with high heterogeneity, sensitivity analysis showed that excluding any one single study did not change the statistical results. Therefore, we believe that the inverse variance (IV) random effects model is also suitable for our study. Many of the outcomes for pain scores and opioid consumption were subgroup analyses, so the outcomes in our study were not actually more than seven. Moreover, all outcomes were separately listed in the form of charts in the article. Finally, spinal anaesthesia was only used in the study of Seangleulur et al., and the statistical results did not change when it was excluded .
Finally, we would like to thank the commentators for their questions regarding our article. This gave us the chance to revisit our article and demonstrates the need for large multi-center randomized controlled trials.
- Min H, Ouyang Y, Chen G (2020) Anterior cruciate ligament reconstruction with the use of adductor canal block can achieve similar pain control as femoral nerve block. Knee Surg Sports Traumatol Arthrosc 28(8):2675
- Seangleulur A, Manuwong S, Chernchujit B, Worathongchai S, Sorin T (2019) Comparison of post-operative analgesia between adductor canal block and femoral nerve block after arthroscopic anterior cruciate ligament reconstruction: a randomized controlled trial. J Med Assoc Thai 102(3):335–342.
3. The deep lateral femoral notch sign: a reliable diagnostic tool in identifying a concomitant anterior cruciate and anterolateral ligament injury
Dimitriou, D., Reimond, M., Foesel, A. et al. Knee Surg Sports Traumatol Arthrosc 29, 1968–1976 (2021).
Query Letter to the Editor
Konrad Malinowski, Michał Ebisz, Paweł Skowronek, Robert F LaPrade, Marcin Mostowy
With great interest we have read the paper: “The deep lateral femoral notch sign: a reliable diagnostic tool in identifying a concomitant anterior cruciate and anterolateral ligament injury” by Dimitriou D., Reimond M., et al. published in Knee Surgery, Sports Traumatology, Arthroscopy (2021) .
We acknowledge the authors’ efforts to confirm the efficacy of deep lateral femoral notch sign (DLFNS) for the diagnosis of anterolateral ligament (ALL) injury.
Nevertheless, we would like to raise a concern.
As stated in the study by Dimitriou et al., “An ACL rupture was confirmed clinically by a positive Lachman and anterior drawer test [7, 12], whereas an ALL rupture was confirmed clinically with a positive pivot-shift test” .
We are concerned about how this paper oversimplifies the concept of rotatory instability. Without referencing any studies, the authors deemed a positive pivot-shift test to be a sign of an ALL rupture. To our knowledge there is no study “equalizing” a positive pivot shift with a clinical confirmation of ALL injury. The main source of positive pivot-shift is an ACL injury itself [1, 14, 19]. In their classic study, Parsons et al. evaluated the contribution of different structures to an internal rotation moment, describing knee rotational stability . In 25 degrees of knee flexion, the ACL percentage contribution was 30%, 95%CI 21-38%; while at the same knee flexion angle, the ALL percentage contribution to internal rotation moment was 18%, 95%CI 12-23% . This biomechanical claim is also supported by the recent meta-analysis by Mouarbes et al., who reported that an ACL reconstruction with a quadriceps tendon autograft and no additional anterolateral procedures resulted in a negative (grade 0) pivot shift in 84.8% of cases (95% CI, 82.4% – 87.1%) and in a negative or trace pivot-shift (grade 0 or 1) in 97.0% of cases (95% CI, 95.9% – 98.1%) . Therefore, while an ALL injury obviously plays a role in rotatory instability and may increase the grade of pivot-shift test, we would like to emphasize that the main source of positive pivot-shift is an ACL injury.
In addition, there are numerous studies pointing out pathologies or osseous morphology other than an ALL injury that increase the risk of pivot-shift presence or grade, such as meniscal injuries [7, 8, 12, 13, 18], Kaplan fibers injuries [4, 5], tibial slope [16, 18] or distal femoral morphology [15, 17]. Recent publication by Jacquet et al. presented the results of a group of 266 patients who all had a high-grade pivot shift preoperatively and underwent ACL reconstruction with or without additional anterolateral procedure. Their data proved that “repairing a pre-existing meniscal lesion was more effective than performing LET to decrease the presence of a high-grade pivot-shift at follow-up” . To add up, Dimitriou et al. assessed rotatory instability in patients with a positive DLFNS. Multiple studies have reported the presence of a DLFNS to be associated with an increased risk of LM injuries, especially lateral meniscus posterior root tears [2, 6, 10], and the role of the LM in rotatory stability of the knee is well established [7, 13, 18]. It is also not known whether deep impaction fractures of the lateral femoral condyle (LFC) do not cause a “bony” instability, similarly to the Hill-Sachs lesion in the shoulder [6, 9].
One should not assume a positive pivot-shift equates to a concomitant ALL injury, because an isolated ACL injury can cause a positive pivot-shift by itself. It is also inconclusive whether an ALL injury is really the most important concomitant “enhancer” of rotatory instability. In light of current evidence, an increased pivot shift grade is the result of an interplay between knee anatomy and complex injury morphology rather than being straightforwardly caused by a single ligament tear. We believe that the abovementioned clarifications will be of value, especially for young surgeons with less experience in the evaluation of injured knee. While simplifying the concepts concerning knee instability allows for an easier understanding of the topic, we believe that solely equalizing a positive pivot-shift with a presumed concomitant clinical confirmation of ALL injury is oversimplification.
- Barrera CM, Arizpe A, Wodicka R, Lesniak BP, Baraga MG, Kaplan L, Jose J (2018) Anterolateral ligament injuries on magnetic resonance imaging and pivot-shift testing for rotational laxity. J Clin Orthop Trauma 9:312–316
- Bernholt DL, DePhillipo NN, Crawford MD, Aman ZS, Grantham WJ, LaPrade RF (2020) Incidence of Displaced Posterolateral Tibial Plateau and Lateral Femoral Condyle Impaction Fractures in the Setting of Primary Anterior Cruciate Ligament Tear. Am J Sports Med 48:545–553
- Dimitriou D, Reimond M, Foesel A, Baumgaertner B, Zou D, Tsai TY, Helmy N (2020) The deep lateral femoral notch sign: a reliable diagnostic tool in identifying a concomitant anterior cruciate and anterolateral ligament injury. Knee Surgery, Sport Traumatol Arthrosc 29:1968–1976
- Geeslin AG, Chahla J, Moatshe G, Muckenhirn KJ, Kruckeberg BM, Brady AW, Coggins A, Dornan GJ, Getgood AM, Godin JA, LaPrade RF (2018) Anterolateral Knee Extra-articular Stabilizers: A Robotic Sectioning Study of the Anterolateral Ligament and Distal Iliotibial Band Kaplan Fibers. Am J Sports Med 46:1352–1361
- Geeslin AG, Moatshe G, Chahla J, Kruckeberg BM, Muckenhirn KJ, Dornan GJ, Coggins A, Brady AW, Getgood AM, Godin JA, LaPrade RF (2018) Anterolateral Knee Extra-articular Stabilizers: A Robotic Study Comparing Anterolateral Ligament Reconstruction and Modified Lemaire Lateral Extra-articular Tenodesis. Am J Sports Med 46:607–616
- Herbst E, Hoser C, Tecklenburg K, Filipovic M, Dallapozza C, Herbort M, Fink C (2015) The lateral femoral notch sign following ACL injury: frequency, morphology and relation to meniscal injury and sports activity. Knee Surgery, Sport Traumatol Arthrosc 23:2250–2258
- Hoshino Y, Hiroshima Y, Miyaji N, Nagai K, Araki D, Kanzaki N, Kakutani K, Matsushita T, Kuroda R (2020) Unrepaired lateral meniscus tears lead to remaining pivot-shift in ACL-reconstructed knees. Knee Surgery, Sport Traumatol Arthrosc 28:3504–3510
- Jacquet C, Pioger C, Seil R, Khakha R, Parratte S, Steltzlen C, Argenson JN, Pujol N, Ollivier M (2021) Incidence and Risk Factors for Residual High-Grade Pivot Shift After ACL Reconstruction With or Without a Lateral Extra-articular Tenodesis. Orthop J Sport Med 9:doi: 10.1177/23259671211003590
- Kanakamedala AC, Burnham JM, Pfeiffer TR, Herbst E, Kowalczuk M, Popchak A, Irrgang J, Fu FH, Musahl V (2018) Lateral femoral notch depth is not associated with increased rotatory instability in ACL-injured knees: a quantitative pivot shift analysis. Knee Surgery, Sport Traumatol Arthrosc 26:1399–1405
- Kim SH, Seo J-H, Kim D-A, Lee J-W, Kim K-I, Lee SH (2021) Steep posterior lateral tibial slope, bone contusion on lateral compartments and combined medial collateral ligament injury are associated with the increased risk of lateral meniscal tear. Knee Surgery, Sport Traumatol Arthrosc doi: 10.1007/s00167-021-06504-z
- Mouarbes D, Menetrey J, Marot V, Courtot L, Berard E, Cavaignac E (2019) Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Outcomes for Quadriceps Tendon Autograft Versus Bone–Patellar Tendon–Bone and Hamstring-Tendon Autografts. Am J Sports Med 47:3531–3540
- Mouton C, Magosch A, Pape D, Hoffmann A, Nührenbörger C, Seil R (2020) Ramp lesions of the medial meniscus are associated with a higher grade of dynamic rotatory laxity in ACL-injured patients in comparison to patients with an isolated injury. Knee surgery, Sport Traumatol Arthrosc 28:1023–1028
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- Pfeiffer TR, Burnham JM, Kanakamedala AC, Hughes JD, Zlotnicki J, Popchak A, Debski RE, Musahl V (2019) Distal femur morphology affects rotatory knee instability in patients with anterior cruciate ligament ruptures. Knee Surg Sports Traumatol Arthrosc 27:1514–1519
- Rahnemai-Azar AA, Abebe ES, Johnson P, Labrum J, Fu FH, Irrgang JJ, Samuelsson K, Musahl V (2017) Increased lateral tibial slope predicts high-grade rotatory knee laxity pre-operatively in ACL reconstruction. Knee Surg Sports Traumatol Arthrosc 25:1170–1176
- Saita Y, Schoenhuber H, Thiébat G, Ravasio G, Pozzoni R, Panzeri A, Galli M, Nagao M, Takazawa Y, Ikeda H, Kaneko K (2019) Knee hyperextension and a small lateral condyle are associated with greater quantified antero-lateral rotatory instability in the patients with a complete anterior cruciate ligament (ACL) rupture. Knee surgery, Sport Traumatol Arthrosc 27:868–874
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Response from authors
With great interest, we have read the letter to the Editor regarding our paper: “The deep lateral femoral notch sign: a reliable diagnostic tool in identifying a concomitant anterior cruciate and anterolateral ligament injury” by Dimitriou D., et al. published in Knee Surgery, Sports Traumatology, Arthroscopy (2021).
We would like to thank the authors for their invaluable input and the concern they raised.
The diagnosis of a concomitant anterior cruciate ligament (ACL) anterolateral ligament (ALL) rupture is nowadays still challenging. For the above-mentioned study, we used both MRI findings suggestive of an ALL injury “ The ALL was identified according to the recommendations suggested by Patel et al. (Fig. 2a). An ALL rupture was diagnosed on MRI according to Muramatsu et al.’s recommendations as warping, thinning, iso-signal changes of the ALL, or loss of continuity (Fig. 2b)” but also the clinical findings as the authors mentioned “An ACL rupture was confirmed clinically by a positive Lachman and anterior drawer test, whereas an ALL rupture was confirmed clinically with a positive pivot-shift test”. Furthermore, as mentioned in the paper “if there was a discrepancy between the clinical and MRI findings, the patients were excluded from the study”.
The authors stated that without referencing any studies, we deemed that a positive pivot-shift test is a sign of an ALL rupture, and they add up that no study “equalizing” a positive pivot shift with a clinical confirmation of an ALL injury. As far as we know, we are not aware of how a study could clinically confirm an ALL injury other than a pivot-shift test. Nevertheless, several biomechanical studies support that an ALL-rupture in an ACL-deficient knee results in a significant increase in internal rotation and pivot shift. Specifically, Bonanzing et al. in biomechanical analysis of 10 fresh-frozen knees under intact ACL, deficient ACL, and deficient ACL + ALL reported that cutting of the ACL showed no significant difference in acceleration during the manual pivot-shift test, whereas the ACL+ALL deficient knee had significantly more acceleration than the intact knee during the pivot-shift test. Another biomechanical study from Inderhaug et al. investigated cadaveric knees in the following 8 conditions (1) intact knee, (2) ACL-transected, (3) combined ACL plus ALL lesion, (4) isolated ACL reconstruction, (5) ACL reconstruction combined with ALL reconstruction, (6) ACL reconstruction and a combined MacIntosh procedure, (7) ACL reconstruction and a combined Lemaire procedure deep to the LCL, and (8) ACL reconstruction and a combined Lemaire procedure superficial to the LCL under 90-N anterior drawer force, 5-N internal tibial torque, and combined 90-N anterior drawer force and 5-N internal tibial torque, across 0° to 90° of knee flexion. They concluded that isolated intra-articular ACL reconstruction leaves residual knee laxity, in terms of anterior translation and internal rotation, when a combined ACL plus anterolateral lesion is present. Furthermore, numerous studies reported a significant increase in tibial internal rotation or pivot shift after ALL resection in ACL-deficient knees  
The authors also claim that the main source of positive pivot-shift is an ACL injury itself and reference the study by Parsons et al., which states that in 25 degrees of knee flexion, the ACL percentage contribution was 30%, 95%CI 21-38%; while at the same knee flexion angle, the ALL percentage contribution to internal rotation moment was 18%, 95%CI 12-23% . However, the same study states that the knee flexion angles greater than 30°, the contribution of the ALL exceeded that of the ACL. For example, at 60° of knee flexion, the contribution of ALL is 44%, 95%CI 37-50%, while at the same knee flexion angle, the ACL percentage contribution to internal rotation moment was only 15%, 95% CI 10-20% . The authors, to support their thesis, reference a recent meta-analysis by Mouarbes et al. , who reported that an ACL reconstruction with a quadriceps tendon autograft and no additional anterolateral procedures resulted in a negative (grade 0) pivot shift in 84.8% of cases . However, in the abovementioned meta-analysis, it was not mentioned whether the patients had a positive pivot-shift test preoperative. Several studies reported that the most important risk factor for residual pivot shift after ACL reconstruction was the preoperative pivot shift  . Furthermore, the rest 15% of the patients with a residual pivot-shift complies with the percentage of patients with concomitant ACL/ALL lesion reported in our study .
We agree with the authors that osseous morphology increases the risk of pivot-shift presence or grade, that is why we excluded those patients from our study. As stated, “ Exclusion criteria were age > 40 years, history of patellofemoral instability, previous surgery or symptoms in the affected knee, posterior tibia slope > 7°, clinically excessive varus/valgus leg axis, and Segond fracture (as these patients were treated with a combined intra-articular ACL reconstruction and extra-articular tenodesis)”. The authors also cited the study from Jacquet et al. , to support the idea that repairing a pre-existing meniscal lesion was more effective than performing an extra-articular tenodesis (LET) to decrease the presence of a high-grade pivot-shift at follow-up. However, the same study concluded that “1 in 4 patients with high-grade pivot-shift before ACLR with or without LET was at risk of residual rotatory knee laxity at mean 44-month follow-up, regardless of the technique used” . Furthermore, it should be noted that the LET graft was fixed in 20° of knee flexion in that study. A biomechanical study by Inderhaug et al. concluded that in combined anterolateral procedure plus intra-articular ACL reconstruction, the knee flexion angle is important when fixing the graft. Although a modified Lemaire procedure could restore intact knee laxities when fixation was performed at 0°, 30°, or 60° of flexion, the ALL procedure could restore normal laxities only when fixation occurred in full extension. The MAKS group in a large multicenter study with 368 patients analyzed the risk factors for residual pivot-shift following a single-bundle ACL reconstruction (without ALL reconstruction or LET) and found that 15% of the patients had a residual high-grade pivot-shift . The meniscus repair or meniscectomy was also not a risk factor for residual instability. Also, the ALL has attachments to the body of the lateral meniscus . As reported by Van Dyck et al., in patients with an ACL rupture and intact ALL, 31 % had a torn lateral meniscus as compared to 61 % with an abnormal ALL (p = 0.008). These data might suggest that a torn lateral meniscus might be a confounder to the rotational instability and not the cause for the rotational instability, as it might hide an undiagnosed ALL-rupture. The authors also state a bony instability similar to the Hill-Sachs might result in rotational instability. However, to the best of our knowledge, no biomechanical or clinical studies support this theory.
We agree with the statement of the authors that it should not be assumed that a positive pivot-shift equates to a concomitant ALL injury, but we believe that the MRI images of patients with high-grade pivot shift test should be carefully evaluated to look for associated injuries, especially at the anterolateral/posterolateral corner of the knee. Although the ACL might be the main constrain to internal rotation of the tibia or pivot-shift test (at least until 30° of flexion), in ACL deficient knees, the role of ALL or the anterolateral corner of the knee should not be ignored. As the pivot-shift test is subjective and challenging to perform in an acute injury due to pain, a DLFNS>1.8 mm could be a valuable and straightforward screening tool without extra costs to detect a concomitant injury to the lateral corner of the knee. Whether an ALL reconstruction or LET is needed, we could not address that in our study, but it should be stated that according to the literature, 15% of the patients with a high pivot-shift test preoperative demonstrate a residual rotational instability following a single-bundle ACL reconstruction without a LET .
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- Dimitriou D, Reimond M, Foesel A, Baumgaertner B, Zou D, Tsai T-Y, et al. (2020) The deep lateral femoral notch sign: a reliable diagnostic tool in identifying a concomitant anterior cruciate and anterolateral ligament injury. Knee Surgery, Sports Traumatology, Arthroscopy 1-9
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- Jacquet C, Pioger C, Seil R, Khakha R, Parratte S, Steltzlen C, et al. (2021) Incidence and Risk Factors for Residual High-Grade Pivot Shift After ACL Reconstruction With or Without a Lateral Extra-articular Tenodesis. Orthopaedic Journal of Sports Medicine 9:23259671211003590
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- Mouarbes D, Menetrey J, Marot V, Courtot L, Berard E, Cavaignac E (2019) Anterior cruciate ligament reconstruction: a systematic review and meta-analysis of outcomes for quadriceps tendon autograft versus bone–patellar tendon–bone and hamstring-tendon autografts. The American journal of sports medicine 47:3531-3540
- Parsons EM, Gee AO, Spiekerman C, Cavanagh PR (2015) The biomechanical function of the anterolateral ligament of the knee. The American journal of sports medicine 43:669-674
- Ruiz N, Filippi GJ, Gagnière B, Bowen M, Robert HE (2016) The comparative role of the anterior cruciate ligament and anterolateral structures in controlling passive internal rotation of the knee: a biomechanical study. Arthroscopy: The Journal of Arthroscopic & Related Surgery 32:1053-1062
- Ueki H, Nakagawa Y, Ohara T, Watanabe T, Horie M, Katagiri H, et al. (2018) Risk factors for residual pivot shift after anterior cruciate ligament reconstruction: data from the MAKS group. Knee Surgery, Sports Traumatology, Arthroscopy 26:3724-3730
- Van Dyck P, Clockaerts S, Vanhoenacker FM, Lambrecht V, Wouters K, De Smet E, et al. (2016) Anterolateral ligament abnormalities in patients with acute anterior cruciate ligament rupture are associated with lateral meniscal and osseous injuries. European radiology 26:3383-3391
4. Posterior tibial slope: the fingerprint of the tibial bone
Winkler, P.W., Godshaw, B.M., Karlsson, J. et al. Knee Surg Sports Traumatol Arthrosc 29, 1687–1689 (2021)
Query Letter to the Editor
Stanley E. Kim, Antonio Pozzi, Daniel D. Lewis, Selena Tinga, Stephen C. Jones, Scott A. Banks
With great interest we read the editorial entitled ‘Posterior tibial slope: the fingerprint of the tibial bone’. The authors suggest the posterior tibial slope (PTS) has only recently become an important consideration when evaluating patients with anterior cruciate ligament (ACL) injury, and they succinctly assessed landmark studies supporting the concept that an increased PTS can be detrimental to the ACL. The authors also encouraged further research on the topic since much remains unknown about sagittal alignment-altering high tibial osteotomies.
We were compelled to respond to this editorial because as veterinary surgeons we have been performing PTS-altering procedures to address ACL injuries for decades. The canine ACL is prone to degeneration, and ACL rupture is the most common indication for orthopedic surgery in dogs. Our group, consisting of veterinary clinician-scientists and biomechanical engineers, is one of many in the veterinary orthopedic community with a strong interest in the biomechanics of PTS-altering procedures. From our perspective, the omission of an acknowledgement of work beyond human studies in the editorial was striking, and we thought it would be a good opportunity to bring awareness of influential studies in dogs to the authors and broad readership of this journal.
The PTS of dogs is relatively steep at approximately 30 degrees; consequently, anterior tibial subluxation with ACL deficiency is much more pronounced than what is observed in humans , and ACL grafts routinely fail. In 1984, small animal surgeon Barclay Slocum (who was, probably not coincidentally, son of renowned orthopedic surgeon Donald Slocum) first proposed ‘leveling’ the tibial slope, without performing an ACL graft, as a primary method to eliminate subluxation in ACL-deficient knees . After several iterations, Slocum developed the tibial plateau leveling osteotomy (TPLO) , and the concept proved so successful that TPLO is now widely regarded as the gold-standard treatment option for ACL rupture in dogs.
As such, our research community is well versed in PTS biomechanics, and we share many concerns and questions raised in the editorial. Veterinary research groups have investigated effects of PTS-decreasing osteotomies on several important knee-related structures including the posterior cruciate ligament , collateral ligaments , menisci , and articular cartilage . Our group has a particular interest in in-vivo knee kinematics, and in a recently published fluoroscopic study of ACL deficient client-owned dogs , we were able to provide some insight into the changes in sagittal translations and axial rotations induced by TPLO. In other clinical reports, TPLO appeared to halt progression of ACL degeneration , but the procedure has also been associated with unique complications such as severe cartilage wear , posterior cruciate ligament rupture , patellar tendinitis , and patellar fracture .
The mechanism of ACL rupture may also share similar degenerative features between species, as it was recently hypothesized that repetitive sub-maximal loading of human knees causes ACL fatigue failure , as is purported to occur in dogs. Spontaneous disease models in companion animals are well established for exploring a variety of human conditions , and a One Health approach could be particularly fruitful for investigating ACL rupture as it relates to PTS in both species.
We have highlighted only a fraction of the substantial literature pertaining to PTS-decreasing osteotomies in dogs. Research groups primarily interested in veterinary-related issues will routinely comb through relevant human-centric investigations for translatable knowledge. As the human orthopedic research community grapples with the relevance of PTS and ACL rupture, we would suggest that perusing the veterinary orthopedic literature may also be enlightening.
- Winkler PW, Godshaw BM, Karlsson J, Getgood AMJ, Musahl V (2021) Posterior tibial slope: the fingerprint of the tibial bone. Knee Surg Sports Traumatol Arthrosc. 29(6):1687-1689.
- Tinga S, Kim SE, Banks SA, Jones SC, Park BH, Pozzi A, Lewis DD (2018) Femorotibial kinematics in dogs with cranial cruciate ligament insufficiency: a three-dimensional in-vivo fluoroscopic analysis during walking. BMC Vet Res. 14(1):85.
- Slocum B, Devine T (1984) Cranial tibial wedge osteotomy: a technique for eliminating cranial tibial thrust in cranial cruciate ligament repair. J Am Vet Med Assoc. 184:564-569.
- Slocum B, Slocum TD (1994) Tibial plateau leveling osteotomy for repair of cranial cruciate ligament rupture in the canine. Vet Clin North Am Small Anim Pract. 23(4):777-95.
- Warzee CC, Dejardin LM, Arnoczky SP, Petty RL (2001) Effect of tibial plateau leveling on cranial and caudal tibial thrusts in canine cranial cruciate–deficient stifles: An in vitro experimental study. Vet Surg. 30:278-286.
- Shimada M, Takagi T, Kanno N, Yamakawa S, Fujie H, Ichinohe T, Suzuki S, Harada Y, Hara Y (2020) Biomechanical Effects of Tibial Plateau Levelling Osteotomy on Joint Instability in Normal Canine Stifles: An In Vitro Study. Vet Comp Orthop Traumatol. 33(5):301-307.
- Pozzi A, Kowaleski MP, Apelt D, Meadows C, Andrews CM, Johnson KA (2006) Effect of medial meniscal release on tibial translation after tibial plateau leveling osteotomy. Vet Surg. 35(5):486-94.
- Kim SE, Pozzi A, Banks SA, Conrad BP, Lewis DD (2009) Effect of tibial plateau leveling osteotomy on femorotibial contact mechanics and stifle kinematics. Vet Surg. 38(1):23-32.
- Tinga S, Kim SE, Banks SA, Jones SC, Park BH, Burtch M, Pozzi A, Lewis DD (2020) Femorotibial kinematics in dogs treated with tibial plateau leveling osteotomy for cranial cruciate ligament insufficiency: An in vivo fluoroscopic analysis during walking. Vet Surg. 49(1):187-199.
- Hulse D, Beale B, Kerwin S (2010) Second look arthroscopic findings after tibial plateau leveling osteotomy. Vet Surg. 39(3):350-4.
- Carey K, Aiken SW, DiResta GR, Herr LG, Monette S (2005) Radiographic and clinical changes of the patellar tendon after tibial plateau leveling osteotomy 94 cases (2000-2003). Vet Comp Orthop Traumatol. 18(4):235-42.
- Wojtys EM, Beaulieu ML, Ashton-Miller JA (2016) New perspectives on ACL injury: On the role of repetitive sub-maximal knee loading in causing ACL fatigue failure. J Orthop Res. 34(12):2059-2068.
- Kol A, Arzi B, Athanasiou KA, Farmer DL, Nolta JA, Rebhun RB, Chen X, Griffiths LG, Verstraete FJ, Murphy CJ, Borjesson DL (2015) Companion animals: Translational scientist’s new best friends. Sci Transl Med. 7(308):308ps21.
Response from authors:
We would like to thank Kim and colleagues for the interesting and instructive comment on our editorial “Posterior Tibial Slope: The Fingerprint of the Tibial Bone“ . Surgical modification of the posterior tibial slope (PTS) to treat sagittal knee instability in dogs is a standard procedure in veterinary medicine for decades. The reported expertise of experienced veterinary surgeons and basic scientists is a valuable asset to orthopedic community. We appreciate the precious work by veterinarians and were aware that the experience of PTS-altering osteotomies (i.e., tibial plateau leveling osteotomies (TPLO)) in dogs has contributed to the development of PTS-altering osteotomies in humans [6, 7]. Given the clinical focus of Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA), we decided for our editorial to focus on biomechanical and clinical findings developed in human knee joints.
However, we would like to share some experiences from the University of Pittsburgh to highlight our ambition for interdisciplinary collaboration. Our teacher of anterior cruciate ligament (ACL) surgery – Freddie H. Fu – has taught us many lessons about his experience dissecting knee joints of various species [3, 8]. In one study, the anatomy of the ACL was compared between human knees and knees of 6 different animal species. Similar bundle configurations, fibre orientations, and insertion sites of the ACL have been observed in the investigated species . A subsequent study evaluated the lateral anatomy of the human knee and 23 different animal species, showing similar results regarding ligamentous anatomy . Although not quantitatively assessed, differences in the bony morphology of the knee joints of the different species were striking . The insights Freddie has gained from working with animal knees have improved our understanding of anatomy and biomechanics and have contributed to the development of state-of-the-art individualized ACL surgery . In collaboration with Pittsburgh Zoo and Carnegie Natural History Museum, the complex interplay of bony morphology and knee ligaments became apparent. We have learned that it is not only the ligaments that prevent rotatory knee instability, but rather the three-dimensional bony morphology and the sophisticated interplay between bone and soft tissues. Consequently, we believe that we should pay attention to the veterinary literature in order to achieve the best possible progress.
Research efforts and many years of experience have turned TPLO in dogs into a save, standardized, and repeatable procedure in the treatment of ACL injury . Although the complication rate ranges from 10-34%, only 2-4% of dogs undergoing TPLO require revision surgery . Experiences in patient selection, preoperative planning, and various surgical techniques, underscore the scientific and clinical advancement of veterinary surgeons compared to orthopedic surgeons regarding PTS-altering osteotomies [2, 4]. Collaboration between orthopedic surgeons, veterinarians, and basic scientists should be encouraged in the future to further improve our understanding and treatment of sagittal and rotatory knee instability.
- Bergh MS, Peirone B (2012) Complications of tibial plateau levelling osteotomy in dogs. Vet Comp Orthop Traumatol 25:349-358
- Fujino H, Honnami M, Mochizuki M (2020) Preoperative planning for tibial plateau leveling osteotomy based on proximal tibial width. J Vet Med Sci 82:661-667
- Ingham SJM, de Carvalho RT, Martins CAQ, Lertwanich P, Abdalla RJ, Smolinski P, et al. (2017) Anterolateral ligament anatomy: a comparative anatomical study. Knee Surg Sports Traumatol Arthrosc 25:1048-1054
- Nanda A, Hans EC (2019) Tibial Plateau Leveling Osteotomy for Cranial Cruciate Ligament Rupture in Canines: Patient Selection and Reported Outcomes. Vet Med (Auckl) 10:249-255
- Offerhaus C, Albers M, Nagai K, Arner JW, Höher J, Musahl V, et al. (2018) Individualized Anterior Cruciate Ligament Graft Matching: In Vivo Comparison of Cross-sectional Areas of Hamstring, Patellar, and Quadriceps Tendon Grafts and ACL Insertion Area. Am J Sports Med 46:2646-2652
- Slocum B, Devine T (1984) Cranial tibial wedge osteotomy: a technique for eliminating cranial tibial thrust in cranial cruciate ligament repair. J Am Vet Med Assoc 184:564-569
- Slocum B, Slocum TD (1993) Tibial plateau leveling osteotomy for repair of cranial cruciate ligament rupture in the canine. Vet Clin North Am Small Anim Pract 23:777-795
- Tantisricharoenkul G, Linde-Rosen M, Araujo P, Zhou J, Smolinski P, Fu FH (2014) Anterior cruciate ligament: an anatomical exploration in humans and in a selection of animal species. Knee Surg Sports Traumatol Arthrosc 22:961-971
- Winkler PW, Godshaw BM, Karlsson J, Getgood AMJ, Musahl V (2021) Posterior tibial slope: the fingerprint of the tibial bone. Knee Surg Sports Traumatol Arthrosc 29:1687-1689
5. Peroneus longus tendon autograft has functional outcomes comparable to hamstring tendon autograft for anterior cruciate ligament reconstruction: a systematic review and meta-analysis
He, J., Tang, Q., Ernst, S. et al. Knee Surg Sports Traumatol Arthrosc 29, 2869–2879 (2021)
Query Letter to the Editor
Marín Fermín T, MD; Hovsepian JM, MD; Symeonidis PD, MD, PhD; Terzidis I, BSc, MD, PhD, FEBSM; Papakostas ET, MD, FEBSM.
We have read with great interest the paper “Peroneus longus tendon autograft has functional outcomes comparable to hamstring tendon autograft for anterior cruciate ligament reconstruction: a systematic review and meta-analysis” by He J, Tang Q, Ernst S, Linde M, Smolinski P, Wu S, Fu F , published in Knee Surgery, Sports Traumatology, Arthroscopy (2020).
The authors have made a remarkable effort to gather all available evidence on the subject. Indeed, peroneus longus tendon (PLT) autograft offers a viable option for anterior cruciate ligament reconstruction, and the findings of this meta-analysis support this. Due to its length, mechanical properties, and diameter consistency, the use of PLT has led to functional outcomes comparable to hamstring tendon autograft [3, 8].
Still, as with every tendon transfer, donor-site morbidity is an area of concern. We think this has not been adequately covered in the study of He et al.  The authors did conduct a meta-analysis on donor-site pain or paresthesia as indicators for comparing donor-site morbidity between PLT and hamstring tendon. However, other important PLT donor site morbidity parameters, such as its impact on foot and ankle biomechanics, were not mentioned. According to previous studies where objective measurements were used, harvesting the entire PLT tendon has important implications on eversion weakness [1, 9] and rotatory moment gait alterations [5, 9]. Another potential bias in assessing donor-site morbidity lies in using non-validated and general functional scores such as AOFAS or FADI in some of the studies. This weakness needs to be taken into consideration for the conduction of any relevant meta-analysis.
A promising option to balance between PLT donor site morbidity and adequate tendon strength for an anterior cruciate ligament reconstruction is to harvest half of the tendon’s diameter. We have recently published a critical review on the topic , in which we suggest that harvesting half of the PLT tendon [2, 7, 14, 15] or/and tenodesis to the peroneus brevis tendon [6, 10-12, 13] seem to be safer options for the technique. Still, further studies are needed to evaluate the alterations of foot and ankle after PLT harvesting, using validated objective and subjective scores, such as the PROMIS instead of the AOFAS scores . Moreover, extrapolating evidence of studies referring to harvesting half the PLT tendon to draw conclusions on donor-site morbidity with the use of the whole tendon is erroneous and should be avoided.
In essence, functional outcomes after any given tendon transfer need to refer not only to the recipient but also to the donor site. In the light of the above, we feel that the important parameter of PLT donor site morbidity has not been adequately elucidated in the interesting meta-analysis of He et al.  We would caution against the widespread adoption of the technique until more evidence-based on high-quality studies is accumulated regarding the safety and long-term functional outcomes of the method in both the knee and the foot and ankle regions.
- Angthong C, Chernchujit B, Apivatgaroon A, Chaijenkit K, Nualon P, Suchao-in K. The Anterior Cruciate Ligament Reconstruction with the Peroneus Longus Tendon: A Biomechanical and Clinical Evaluation of the Donor Ankle Morbidity. J Med Assoc Thai. 2015 Jun;98(6):555-60.
- Bi M, Zhao C, Zhang S, Yao B, Hong Z, Bi Q. All-Inside Single-Bundle Reconstruction of the Anterior Cruciate Ligament with the Anterior Half of the Peroneus Longus Tendon Compared to the Semitendinosus Tendon: A Two-Year Follow-Up Study. J Knee Surg. 2018 Nov;31(10):1022-1030.
- He J, Tang Q, Ernst S, Linde MA, Smolinski P, Wu S, Fu F. Peroneus longus tendon autograft has functional outcomes comparable to hamstring tendon autograft for anterior cruciate ligament reconstruction: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2020 Sep 27. DOI: 10.1007/s00167-020-06279-9.
- Hung M, Baumhauer JF, Licari FW, Voss MW, Bounsanga J, Saltzman CL. PROMIS and FAAM Minimal Clinically Important Differences in Foot and Ankle Orthopedics. Foot Ankle Int. 2019 Jan;40(1):65-73.
- Karimi M, Fatoye F, Mirbod SM, Omar H, Nazem K, Barzegar MR, Hosseini A. Gait analysis of anterior cruciate ligament reconstructed subjects with a combined tendon obtained from hamstring and peroneus longus. Knee. 2013 Dec;20(6):526-31.
- Khajotia BL, Chauhan S, Sethia R, Chopra BL. Functional outcome of arthroscopic reconstruction of anterior cruciate ligament tear using peroneus longus tendon autograft. Int J Res Orthop 2018;4:898–903.
- Liu CT, Lu YC, Huang CH. Half-peroneus-longus-tendon graft augmentation for unqualified hamstring tendon graft of anterior cruciate ligament reconstruction. J Orthop Sci. 2015 Sep;20(5):854-60.
- Marín Fermín T, Hovsepian JM, Symeonidis PD, Terzidis I, Papakostas ET. Insufficient evidence to support peroneus longus tendon over other autografts for primary anterior cruciate ligament reconstruction: a systematic review. J ISAKOS. 2021 May;6(3):161-169.
- Nazem K, Barzegar M, Hosseini A, Karimi M. Can we use peroneus longus in addition to hamstring tendons for anterior cruciate ligament reconstruction? Adv Biomed Res. 2014 May 19;3:115.
- Rhatomy S, Asikin AIZ, Wardani AE, Rukmoyo T, Lumban-Gaol I, Budhiparama NC. Peroneus longus autograft can be recommended as a superior graft to hamstring tendon in single-bundle ACL reconstruction. Knee Surg Sports Traumatol Arthrosc. 2019 Nov;27(11):3552-3559.
- Rhatomy S, Hartoko L, Setyawan R, Soekarno NR, Zainal Asikin AI, Pridianto D, Mustamsir E. Single bundle ACL reconstruction with peroneus longus tendon graft: 2-years follow-up. J Clin Orthop Trauma. 2020 May;11(Suppl 3):S332-S336.
- Rhatomy S, Tanzil H, Setyawan R, Amanda C, Phatama KY, Andrianus J, Rukmoyo T, Kisworo B. Influence of anthropometric features on peroneus longus graft diameter in Anterior Cruciate Ligament reconstruction: A cohort study. Ann Med Surg (Lond). 2019 Nov 1;48:77-80.
- Shi FD, Hess DE, Zuo JZ, Liu SJ, Wang XC, Zhang Y, Meng XG, Cui ZJ, Zhao SP, Li CJ, Hu WN. Peroneus Longus Tendon Autograft is a Safe and Effective Alternative for Anterior Cruciate Ligament Reconstruction. J Knee Surg. 2019 Aug;32(8):804-811.
- Trung DT, Manh SL, Thanh LN, Dinh TC, Dinh TC. Preliminary Result of Arthroscopic Anterior Cruciate Ligament Reconstruction Using Anterior Half of Peroneus Longus Tendon Autograft. Open Access Maced J Med Sci. 2019 Dec 20;7(24):4351-4356.
- Zhao J, Huangfu X. The biomechanical and clinical application of using the anterior half of the peroneus longus tendon as an autograft source. Am J Sports Med. 2012 Mar;40(3):662-71.
Response from authors:
We thank Marín Fermín et al. for their interest and comments in the Letter to the Editor regarding our article “Peroneus longus tendon autograft has functional outcomes comparable to hamstring tendon autograft for anterior cruciate ligament reconstruction: a systematic review and meta‑analysis” . We also thank the Knee Surgery, Sports Traumatology, Arthroscopy for the opportunity to respond to this letter.
Anterior cruciate ligament (ACL) reconstruction using peroneus longus tendon (PLT) and hamstring tendon autografts were compared for functional outcomes, knee laxity, and complications in our meta-analysis . No significant difference was observed between either autograft choice with regard to Lachman grade, donor site pain, or graft failure. However, PLT groups demonstrated increased IKDC subjective score and Lysholm score, and decreased AOFAS score at the last post-operative follow-up compared with pre-operative scores.
Our meta-analysis was based on all available published articles about the PLT in ACL reconstruction, thus, we can only make conclusions based on the outcome measures investigated in these articles. To illustrate, the PROMIS score was not reported in these studies, and consequently, it is not possible to conclude whether patients’ PROMIS score significantly differed or not. However, among the 76 scoring systems applied in 669 publications , AOFAS was the most commonly used outcome measurement tool scored by foot and ankle specialists. Indeed, PROMIS, a freely available computerized question bank, has shown capacity for allowing standardization, however, it is just one of several commonly used patient-reported outcome measurements. Objective evaluations such as isometric muscle strength of eversion and first ray plantarflexion after PLT autograft harvest were evaluated by Rhatomy et al.,  and no significant differences were found between the donor site and the contralateral healthy site. Conversely, Angthong et al. reported significantly lower eversion torque at the harvested ankle compared to the contralateral ankle seven months post-operatively . We did discuss this aspect of donor site morbidity, specifically, decreased peak eversion torque, in our meta-analysis, stating “Further investigation should be performed to evaluate the feasibility of PLT autograft in high-level athletes who require quick ankle eversion” As indicated in our meta-analysis , there is no established test to evaluate the function of the PLT in isolation.
We agree that harvesting half of the PLT and/or tenodesis to the peroneus brevis tendon may be a potential way of balancing donor site morbidity and providing adequate tendon strength. As demonstrated by Park et al.,  harvesting the anterior half of the PLT resulted in no difference in mean peak torque for ankle eversion using an objective measurement in the context of lateral ankle ligament reconstruction. As described in a recent article  as well as other references [3, 9], tenodesis of the distal portion of the PLT to the peroneus brevis tendon partially preserves the function of PLT after harvesting. We do not recommend harvesting the full-thickness of proximal PLT autograft by leaving the distal part alone. We also acknowledge that tenodesis was not performed in all papers included in our meta-analysis. As Marín Fermín et al. mentioned, according to the previous study , leaving the distal part alone may lead to eversion weakness. We also reference conflicting evidence published by Nazem et al. , who concluded that that “Removing the PLT has no effect on gait parameters and does not lead to instability of the ankle” by using the procedure we prefer.
To ensure a thorough analysis, we examined donor site function with two subgroups in Figure 1. Interestingly, no statistically significant difference in AOFAS was identified after full-thickness PLT harvest [9, 10] (mean score decreased 0.26; 95% CI -0.80 to 1.31, n.s.), but a statistically significant drop in AOFAS was identified after anterior-half PLT harvest [2, 13–15], (mean score decreased 0.31; 95% CI 0.07 to 0.55, p = 0.01) which exceeded the minimal clinically important difference of 8.9 . Based on current evidence, and as indicated by the team of Marín Fermín et al., harvesting half of the PLT tendon or tenodesis to the peroneus brevis tendon seems to be relatively safe.
Figure 1. Forest plot showing mean difference in AOFAS scores between pre-operation and post-operation.
In conclusion, we appreciate the interest and comments of Marín Fermín et al. about our systematic review and meta-analysis and especially their concerns about donor site morbidity. We agree that further studies are needed to evaluate the alterations of foot and ankle after PLT harvesting with validated objective and subjective scores. The donor site morbidity concerns raised by these authors stems from a divergence of opinions on which autograft constitutes the minor morbidity and results in the best knee function . A more detailed PLT harvesting proposal and evaluation of foot and ankle functions is needed to fully address the benefits and complications. Currently, there is a lack of high-evidence literature with long-term follow-up using PLT autograft. The influence of PLT harvest site morbidity should continue to be evaluated despite literature showing low morbidity in foot and ankle range of motion , strength assessment , and foot arch morphology .
- Angthong C, Chernchujit B, Apivatgaroon A, Chaijenkit K, Nualon P, Suchao-In K (2015) The anterior cruciate ligament reconstruction with the peroneus longus tendon: A biomechanical and clinical evaluation of the donor ankle morbidity. J Med Assoc Thail 98:555–560
- Bi M, Zhao C, Zhang S, Yao B, Hong Z, Bi Q (2018) All-Inside Single-Bundle Reconstruction of the Anterior Cruciate Ligament with the Anterior Half of the Peroneus Longus Tendon Compared to the Semitendinosus Tendon: A Two-Year Follow-Up Study. J Knee Surg 31:1022–1030
- Bimadi MH, Phatama KY, Mustamsir E (2020) Does The Peroneus Longus Tendon Autograft Affect The Ankle Function? A Case Series. Hip Knee J 1:57–62
- Dawson J, Doll H, Coffey J, Jenkinson C (2007) Responsiveness and minimally important change for the Manchester-Oxford foot questionnaire (MOXFQ) compared with AOFAS and SF-36 assessments following surgery for hallux valgus. Osteoarthritis Cartilage 15:918–931
- He J, Byrne K, Ueki H, Kanto R, Linde MA, Smolinski P, Wu S, Fu F (2021) Low to moderate risk of nerve damage during peroneus longus tendon autograft harvest. Knee Surg Sports Traumatol Arthrosc. Doi: 10.1007/s00167-021-06698-2
- He J, Tang Q, Ernst S, Linde MA, Smolinski P, Wu S, Fu F (2021) Peroneus longus tendon autograft has functional outcomes comparable to hamstring tendon autograft for anterior cruciate ligament reconstruction: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc 29:2869-2879
- Nazem K, Barzegar M, Hosseini A, Karimi M (2014) Can we use peroneus longus in addition to hamstring tendons for anterior cruciate ligament reconstruction? Adv Biomed Res 3:115
- Park CH, Lee WC (2017) Donor site morbidity after lateral ankle ligament reconstruction using the anterior half of the per- oneus longus tendon autograft. Am J Sports Med 45:922–928
- Rhatomy S, Wicaksono FH, Soekarno NR, Setyawan R, Primasara S, Budhiparama NC (2019) Eversion and First Ray Plantarflexion Muscle Strength in Anterior Cruciate Ligament Reconstruction Using a Peroneus Longus Tendon Graft. Orthop J Sports Med 7: 2325967119872462
- Shao X, Shi LL, Bluman EM, Wang S, Xu X, Chen X, Wang J (2020) Satisfactory functional and MRI outcomes at the foot and ankle following harvesting of full thickness peroneus longus tendon graft. Bone Joint J 102:205–211
- Safavi PS, Janney C, Jupiter D, Kunzler D, Bui R, Panchbhavi VK (2019) A Systematic Review of the Outcome Evaluation Tools for the Foot and Ankle. Foot Ankle Spec 12:461–470
- Sinding KS, Nielsen TG, Hvid LG, Lind M, Dalgas U (2020) Effects of Autograft Types on Muscle Strength and Functional Capacity in Patients Having Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial. Sports Med 50:1393–1403
- Trung DT, Le Manh S, Thanh LN, Dinh TC, Dinh TC (2019) Preliminary result of arthroscopic anterior cruciate ligament reconstruction using anterior half of peroneus longus tendon autograft. Open Access Maced J Med Sci 7:4351–4356
- Wu C, Xie G, Jin W, Ren Z, Xue J, Yang K (2019) Arthroscopic graftlink technique reconstruction combined with suture anchor fixation for anterior cruciate ligament and medial collateral ligament injuries. Chinese J reparative Reconstr Surg 33:685–688
- Zhao J, Huangfu X (2012) The biomechanical and clinical application of using the anterior half of the peroneus longus tendon as an autograft source. Am J Sports Med 40:662–671
6. Computer-assisted surgery and patient-specific instrumentation improve the accuracy of tibial baseplate rotation in total knee arthroplasty compared to conventional instrumentation: a systematic review and meta-analysis.
Computer-assisted surgery and patient-specific instrumentation improve the accuracy of tibial baseplate rotation in total knee arthroplasty compared to conventional instrumentation: a systematic review and meta-analysis.
Tandogan, R.N., Kort, N.P., Ercin, E. et al. Knee Surg Sports Traumatol Arthrosc (2021). https://doi.org/10.1007/s00167-021-06495-x
Query Letter to the Editor
Han Zhang, Guanhong Chen
We read the published study by Reha N Tandogan and Nanne P Kort that Computer-assisted surgery and patient-specific instrumentation improve the accuracy of tibial baseplate rotation in total knee arthroplasty compared to conventional instrumentation: a systematic review and meta-analysis, carefully. The authors used a meta-analysis to compare the efficacy of conventional instrumentation, patient-specific instrumentation (PSI), computer-assisted surgery (CAS), or robot-assisted surgery (RAS) in terms of deviation from the planned target and the proportion of outliers from the target zone in primary total knee arthroplasty (TKA). Although the authors’ analytical methods are scientific, we think there are some problems in his paper that need to be improved.
- Although the relevant data of CAS and RAS were extracted separately, the authors did not analyze the relevant data of CAS and RAS separately in the Meta-analysis. The authors’ method of combining the relevant data of CAS and RAS into the CAS group for Meta-analysis is not rigorous.
- We noted that in this study, the authors involved a total of four technologies, which were traditional instrumentation, PSI, CAS and RAS. The authors used a dual-arm meta-analysis to compare the efficacy of PSI versus conventional instrumentation and compare the efficacy of CAS versus conventional instrumentation. We think that the network meta-analysis method is more appropriate in this study. In this way, the therapeutic effects of the four therapeutic methods can be comprehensively compared, and the therapeutic effects of the four therapeutic methods can be ranked, so as to provide more effective evidence-based medicine reference for clinicians to select therapeutic methods.
- It is also not rigorous to use the random effects model indiscriminately in the meta-analysis. The random effect model and the fixed effect model should be selected according to the magnitude of heterogeneity. In general, the heterogeneity between studies was tested by I2 statistic with I2≥50% indicating heterogeneity and if no significant heterogeneity existed, a fixed-effects model was adopted,otherwise a random-effects model was used.
Admittedly, the authors’ research is scientifically rigorous. However, we believe that if the above issues are improved, the conclusions drawn from this study will be more instructive to clinical work.
- Tandogan RN, Kort NP, Ercin E, van Rooij F, Nover L, Saffarini M, Hirschmann MT, Becker R, Dejour D; Computer-assisted surgery and patient-specific instrumentation improve the accuracy of tibial baseplate rotation in total knee arthroplasty compared to conventional instrumentation: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc. doi: 10.1007/s00167-021-06495-x.
- Sun P, Bi M, Chen Z (2019). Meta-analysis should be carried out objectively and rigorously. J Clin Anesth 56:6-16. doi: 10.1016/j.jclinane.2018.12.055.
Response from authors:
We thank Zhang and Chen (REF) for their interest in our recent meta-analysis  and for their detailed remarks regarding our study methodology and statistical analyses. Zhang and Chen made 3 remarks regarding:
- Combining the relevant data of CAS and RAS for Meta-analysis.
- Appropriateness of classic meta-analysis (for two-arm comparisons) versus network meta-analysis (for three-arm comparisons).
- Selection of random effects model versus fixed effects model depending on the magnitude of heterogeneity.
The first 2 remarks would have been relevant, had we found eligible studies on all 3 assistive technologies for total knee arthroplasty (TKA): patient-specific instrumentation (PSI), computer-assisted surgery (CAS), or robot-assisted surgery (RAS). Contrary to our expectations, we found no eligible studies that reported any outcomes of interest using RAS, which resulted in a dual-arm meta-analysis, instead of the originally intended triple-arm meta-analysis. While Zhang and Chen may have missed this subtle detail, because we did not specify it explicitly in the text of our Methods or Results sections, it is important to note that we reported this implicitly in the flow-chart, as well as explicitly in the fourth paragraph of our Discussion section, which reads “A formal search for RAS was performed, however, after initial and full-text screening, no eligible studies were found which reported on the deviation from the planned tibial rotational alignment.”
The third remark remains a matter of debate, and the Cochrane Handbook for Systematic reviews  does not provide a universal recommendation. However, they do specify that the choice between a fixed-effects and a random-effects meta-analysis should never be made on the basis of a statistical test for heterogeneity: “Authors should recognize that there is much uncertainty in measures such as I2 and τ2 (when there are few studies). Thus, use of simple thresholds to diagnose heterogeneity should be avoided.”
We were nevertheless pleased to read the sharp advice of Zhang and Chen, which contributes to raising the quality and rigour of systematic reviews and meta-analyses published in the domain of orthopaedic surgery.
- McInnes MDF, Moher D, Thombs BD, McGrath TA, Bossuyt PM, and the P-DTAG, Clifford T, Cohen JF, Deeks JJ, Gatsonis C, Hooft L, Hunt HA, Hyde CJ, Korevaar DA, Leeflang MMG, Macaskill P, Reitsma JB, Rodin R, Rutjes AWS, Salameh JP, Stevens A, Takwoingi Y, Tonelli M, Weeks L, Whiting P, Willis BH (2018) Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies: The PRISMA-DTA Statement. Jama 319 (4):388-396.
- Tandogan RN, Kort NP, Ercin E, van Rooij F, Nover L, Saffarini M, Hirschmann MT, Becker R, Dejour D (2021) Computer-assisted surgery and patient-specific instrumentation improve the accuracy of tibial baseplate rotation in total knee arthroplasty compared to conventional instrumentation: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc.
7. Anterolateral complex injuries occur in the majority of ‘isolated’ anterior cruciate ligament ruptures
Balendra, G., Willinger, L., Pai, V. et al Knee Surg Sports Traumatol Arthrosc (2021). https://doi.org/10.1007/s00167-021-06543-6
Query Letter to the Editor
Breck Lord MA MBBS PhD FRCS, Iswadi Damasena MBBS FRACS, Brian M. Devitt MD PhD FRCS FRACS
It was with interest we read the study by Balendra et al, ‘Anterolateral complex injuries occur in the majority of ‘isolated’ anterior cruciate ligament ruptures’. This study highlights the radiological diagnosis of injury to the anterolateral soft tissue envelope of the knee at the time of anterior cruciate ligament (ACL) rupture. The authors conclude that in a group of professional athletes there is a high incidence of concomitant Anterolateral complex (ALC) injuries in combination with ACL ruptures, with the Kaplan fibres being the most commonly injured structure. This study is of particular relevance considering the Kaplan fibres have gained recent attention for their role in controlling internal rotation of the knee, especially in the setting of ACL deficiency [6, 10-12, 16]. Encouragingly, this study adds to the growing body of research demonstrating the consistent radiological identification of the Kaplan fibres [1, 3, 9, 16, 20]. Furthermore, this study provides important information on the association between radiological evidence of ALC injury and the clinical assessment of anterolateral rotatory laxity with the pivot shift examination. The interpretation of this information and its relevance is critical considering that much of the research to date in this area has focused on cadaveric anatomical and biomechanical sectioning studies[6, 10]. Nonetheless, there remains a certain amount of ambiguity as to what constitutes a clinically relevant ALC injury on MRI and how high the bar should be set when diagnosing injury. This is especially pertinent as a relationship between radiological evidence of Kaplan fibre injury and increased anterolateral rotatory laxity or higher rates of ACL reconstruction failure has not been shown in any clinical series[1, 5].
In the current study, Balendra et al reported a high incidence of injury to the ALC (63%); the majority of injuries were to Kaplan fibres (39% isolated injury and 19% combined with Anterolateral ligament (ALL) injury, while there was a very low incidence of isolated ALL injuries (2%). Interestingly, considering the reported rate of medial collateral ligament injury was also 13%, isolated ACL injury was only seen in 24% of cases, and was described as a ‘rare phenomenon’. In the opening paragraph of the discussion, the authors state that injuries to the ALC ‘especially affect the Kaplan fibres, highlighting the importance of the deep capsule-osseous layer of the iliotibial band in resisting anterolateral rotatory instability.’ Although this may seem like a logical conclusion based on previous biomechanical studies, which examined the role of the Kaplan fibres in controlling tibial translation and rotation, as far as we are aware, there are no clinical studies as yet that have demonstrated an association between Kaplan fibre injury and subjective symptoms of persistent anterolateral rotatory instability following ACL reconstruction. Furthermore, as clearly demonstrated in this study and by others, no correlation has been found between radiological evidence of Kaplan Fibre injury with MRI and the clinical examination of anterolateral rotatory laxity under anaesthesia prior to primary ACL reconstruction[1, 5].
The concept of ‘anterolateral rotatory instability’ of the knee was introduced by Hughston et al in 1976. Notwithstanding the perceptiveness of this theory, one of the lasting challenges has been how to make a definitive diagnosis of injury. The subjective feeling of ‘instability’ may be elicited by a good history but identifying and quantifying anterolateral rotatory laxity has proved an altogether more testing task. Although a number of devices have been used over time to provide an objective assessment anterolateral rotatory laxity, the reliability, accuracy and feasibility of these tools in clinical practice remains questionable[7, 17, 19, 22]. As such, the pivot shift test remains the most widely used clinical examination for anterolateral rotatory laxity[14, 21]. Although this clinical test is subjective it has been shown to have a high specificity for diagnosis of ACL injury [2, 18]. Indeed, assessment of the grade of pivot shift is important as it has been found to correlate with patient outcomes following ACL reconstructive surgery, unlike measurements of anterior knee laxity, which do not.
In the current study, the methods used by the authors are commendable; all of the MRIs were performed within 3 weeks of injury and the clinical examination was carried out under anaesthesia by one, very experienced surgeon at a mean time of just over two-weeks following injury (16.6 ± 13.1 days (3–100). Therefore, one would assume a level of consistency in the diagnosis of anterolateral rotatory laxity in this cohort of patients. Consequently, it seems incongruous that the authors conclude that ‘clinical examination was found to be a poor tool to identify injuries to the ALC, with no association being found between high-grade pivot-shift and injuries to either the ALL or Kaplan fibres.’ This statement seems to imply that the findings of MRI evidence of injury is given a greater level of importance in the diagnosis of ALC injury compared to the clinical interpretation of anterolateral rotatory laxity by an experienced, well-trained surgeon. We suggest that the opposite is true and that MRI might be a ‘poor tool’ in identifying clinically significant ALC injuries. This is alluded to by the authors in the limitations section where they noted that ‘spread of oedema/haematoma might, by MRI criteria, imply injury to soft tissues that are, in fact, intact.’ Further, it has previously been demonstrated that while MRI may have some usefulness for predicting the grade of knee laxity in patients with symptomatic ACL injury, its value is limited[4, 15].
In summary, this study has once again emphasised that the ALC of the knee is complex by name and complex by nature. We agree with authors that ‘there is a great need to develop clear indications for adding lateral augmentation surgery to ACL reconstruction’ but we submit the need for caution in utilising MRI findings to determine the requirement for these additional procedures.
- Balendra G, Willinger L, Pai V, Mitchell A, Lee J, Jones M, et al. (2021) Anterolateral complex injuries occur in the majority of ‘isolated’ anterior cruciate ligament ruptures. Knee Surg Sports Traumatol Arthrosc;10.1007/s00167-021-06543-6
- Benjaminse A, Gokeler A, van der Schans CP (2006) Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis. J Orthop Sports Phys Ther 36:267-288
- Berthold DP, Willinger L, Muench LN, Forkel P, Schmitt A, Woertler K, et al. (2020) Visualization of Proximal and Distal Kaplan Fibers Using 3-Dimensional Magnetic Resonance Imaging and Anatomic Dissection. Am J Sports Med 48:1929-1936
- Chang MJ, Chang CB, Choi JY, Je MS, Kim TK (2014) Can magnetic resonance imaging findings predict the degree of knee joint laxity in patients undergoing anterior cruciate ligament reconstruction? BMC Musculoskelet Disord 15:214
- Devitt BM, Al’khafaji I, Blucher N, Batty LM, Murgier J, Webster KE, et al. (2021) Association Between Radiological Evidence of Kaplan Fiber Injury, Intraoperative Findings, and Pivot-Shift Grade in the Setting of Acute Anterior Cruciate Ligament Injury. Am J Sports Med 49:1262-1269
- Geeslin AG, Chahla J, Moatshe G, Muckenhirn KJ, Kruckeberg BM, Brady AW, et al. (2018) Anterolateral Knee Extra-articular Stabilizers: A Robotic Sectioning Study of the Anterolateral Ligament and Distal Iliotibial Band Kaplan Fibers. Am J Sports Med 46:1352-1361
- Grassi A, Lopomo NF, Rao AM, A.N. A, Zaffagnini S (2016) No proof for the best instrumented device to grade the pivot shift test: a systematic review. . JISAKOS 1:269–275
- Hughston JC, Andrews JR, Cross MJ, Moschi A (1976) Classification of knee ligament instabilities. Part II. The lateral compartment. J Bone Joint Surg Am 58:173-179
- Khanna M, Gupte C, Dodds A, Williams A, Walker M (2018) Magnetic resonance imaging appearances of the capsulo-osseous layer of the iliotibial band and femoral attachments of the iliotibial band in the normal and pivot-shift ACL injured knee. Skeletal Radiol;10.1007/s00256-018-3128-9
- Kittl C, El-Daou H, Athwal KK, Gupte CM, Weiler A, Williams A, et al. (2016) The Role of the Anterolateral Structures and the ACL in Controlling Laxity of the Intact and ACL-Deficient Knee: Response. Am J Sports Med 44:NP15-18
- Kittl C, Halewood C, Stephen JM, Gupte CM, Weiler A, Williams A, et al. (2015) Length change patterns in the lateral extra-articular structures of the knee and related reconstructions. Am J Sports Med 43:354-362
- Kittl C, Inderhaug E, Williams A, Amis AA (2018) Biomechanics of the Anterolateral Structures of the Knee. Clin Sports Med 37:21-31
- Lane CG, Warren R, Pearle AD (2008) The pivot shift. J Am Acad Orthop Surg 16:679-688
- Leblanc MC, Kowalczuk M, Andruszkiewicz N, Simunovic N, Farrokhyar F, Turnbull TL, et al. (2015) Diagnostic accuracy of physical examination for anterior knee instability: a systematic review. Knee Surg Sports Traumatol Arthrosc 23:2805-2813
- Lynch TB, Bernot JM, Oettel DJ, Byerly D, Musahl V, Chasteen J, et al. (2021) Magnetic resonance imaging does not reliably detect Kaplan fiber injury in the setting of anterior cruciate ligament tear. Knee Surg Sports Traumatol Arthrosc;10.1007/s00167-021-06730-5
- Marom N, Greditzer HGt, Roux M, Ling D, Boyle C, Pearle AD, et al. (2020) The Incidence of Kaplan Fiber Injury Associated With Acute Anterior Cruciate Ligament Tear Based on Magnetic Resonance Imaging. Am J Sports Med 48:3194-3199
- Napier RJ, Feller JA, Devitt BM, McClelland JA, Webster KE, Thrush CSJ, et al. (2021) Is the KiRA Device Useful in Quantifying the Pivot Shift in Anterior Cruciate Ligament-Deficient Knees? Orthop J Sports Med 9:2325967120977869
- Ostrowski JA (2006) Accuracy of 3 diagnostic tests for anterior cruciate ligament tears. J Athl Train 41:120-121
- Vaidya RV, Yoo CW, Lee J, Lee MC, Ro DH (2019) Quantitative assessment of the pivot shift test with smartphone accelerometer. Knee Surgery, Sports Traumatology, Arthroscopy;10.1007/s00167-019-05826-3
- Van Dyck P, De Smet E, Roelant E, Parizel PM, Heusdens CHW (2019) Assessment of Anterolateral Complex Injuries by Magnetic Resonance Imaging in Patients With Acute Rupture of the Anterior Cruciate Ligament. Arthroscopy 35:521-527
- van Eck CF, Loopik M, van den Bekerom MP, Fu FH, Kerkhoffs GM (2013) Methods to diagnose acute anterior cruciate ligament rupture: a meta-analysis of instrumented knee laxity tests. Knee Surg Sports Traumatol Arthrosc 21:1989-1997
- Vaudreuil NJ, Rothrauff BB, de Sa D, Musahl V (2019) The Pivot Shift: Current Experimental Methodology and Clinical Utility for Anterior Cruciate Ligament Rupture and Associated Injury. Curr Rev Musculoskelet Med 12:41-49
Response from authors:
We are delighted that Lord et al, read our publication with interest and found our methods ‘commendable’. Most of their letter, makes statements we would not disagree with. We will only deal with issues of disagreement below.
The authors make the point that we described truly isolated ACL rupture as a ‘rare phenomenon’. Their point would seem reasonable given the results in our study, and we should have clarified our statement. However, in another publication in this journal1 we also showed a high association of MCL complex injuries associated with ACL ruptures, and in unpublished studies from our MRI analyses we have recorded high associations of meniscal / chondral lesions with ACL rupture. In that context, and not surprisingly when one considers that the lateral compartment of the knee ‘dislocates’ in the most common mechanism of ACL rupture, truly isolated ACL lesions are uncommon. This point was made in the discussion section of our article in question.
It is in the last 2 paragraphs that Lord et al make other points specifically critical of our publication. Firstly, with reference to our statement: ‘Finally, clinical examination was found to be a poor tool to identify injuries to the ALC, with no association being found between high-grade pivot shift and injuries to either ALL or KF.’ Lord et al state: ‘This statement seems to imply that the findings of MRI evidence of injury is given a greater level of importance in the diagnosis of ALC injury compared to the clinical interpretation of anterolateral rotatory laxity by an experienced, well-trained surgeon.’ We would disagree. Our statement is simply that there was poor correlation between clinical examination, the magnitude of which reflects the degree of anterior tibial translation and anterolateral rotatory laxity, and the MRI findings. Admittedly it would have been clearer if we had written: ‘clinical examination correlated poorly with injuries to the ALC seen on MRI’. There was absolutely no intention of suggesting that MRI trumps good clinical examination- to say so would be completely wrong, and indeed we believe we never stated anything to imply that in our text. MRI demonstrates what is injured but never the degree of injury. This is evident in many aspects of soft tissue knee injury when radiological grades of injury, especially to MCL and PCL, seem not to correlate to clinical laxity findings. MRI is a wonderful tool but needs to be used with care. We would absolutely agree with Lord et al when they state: ‘MRI might be a ‘poor tool’ in identifying clinically significant ALC injuries.’ That much is correct.
We are pleased that Lord et al agree with our statement that ‘there is a great need to develop clear indications for adding lateral augmentation surgery to ACL reconstruction’.
We refute the suggestion that our article implies that MRI findings could be used ‘to determine the requirement for these additional procedures’. In support of that defence, in the discussion section, having just stated our finding that clinical examination did not correlate with MRI findings, we state: ‘It is a pity as there is a great need to develop clear indications for adding lateral augmentation surgery to ACL reconstruction—imaging or clinical tests to identify the cases needing the extra surgery would be invaluable to avoid ACL failure in cases needing LET/ ALL reconstruction, or to avoid unnecessary morbidity and complications in those who do not.’ Thus we were stating that whilst it would be helpful if MRI findings (or clinical tests), could identify patients needing additional procedures such as LET, our study findings meant that MRI findings could not be used. Therefore, we politely and respectfully refute the criticisms made by Lord et al.
- Willinger, L., Balendra, G., Pai, V. et al. Medial meniscal ramp lesions in ACL-injured elite athletes are strongly associated with medial collateral ligament injuries and medial tibial bone bruising on MRI. Knee Surg Sports Traumatol Arthrosc (2021). https://doi.org/10.1007/s00167-021-06671-z
8. Risk factors of de novo hyperextension developed after posterior cruciate ligament substituting total knee arthroplasty: a matched case–control study
Kim, J.S., Cho, C.H., Lee, M.C. et al. Knee Surg Sports Traumatol Arthrosc (2021). https://doi.org/10.1007/s00167-021-06618-4
Query Letter to the Editor
Rujittika Mungmunpuntipantip, Viroj Wiwanitkit
We would like to share ideas on “Risk factors of de novo hyperextension developed after posterior cruciate ligament substituting total knee arthroplasty: a matched case-control study .” Kim et al. concluded that “An increased degree of medial soft tissue release, small preoperative flexion contracture….were risk factors of de novo hyperextension .” Different clinical parameters might affect final outcome. According to a recent report , technique for designs of fixed-bearing is also an important factor associated with postoperative hyperflexion. Experience of surgeon in selection of surgical technique and designing of fixation might be an important concern for a favorable surgical outcome of total knee arthroplasty.
1. Kim JS, Cho CH, Lee MC, Han HS. Risk factors of de novo hyperextension developed after posterior cruciate ligament substituting total knee arthroplasty: a matched case-control study. Knee Surg Sports Traumatol Arthrosc. 2021 May 24. doi: 10.1007/s00167-021-06618-4.
2. Laoruengthana A, Rattanaprichavej P, Suangyanon P, Galassi M, Teekaweerakit P, Pongpirul K. Hyperextension following two different designs of fixed-bearing posterior-stabilized total knee arthroplasty. Eur J Orthop Surg Traumatol. 2021 Oct 19. doi: 10.1007/s00590-021-03150-6.
Response from authors
We would like to thank Rujittika Mungmunpuntipantip for his interest and comments regarding our recent publication entitled “Risk factors of de novo hyperextension developed after posterior cruciate ligament substituting total knee arthroplasty: a matched case-control study.”
We also agree with his opinion that implant design can also contribute to the development of hyperextension. However, in our study, a total of seven types of posterior cruciate ligament substituting total knee implants were included, and matching was performed as the number of cases was not sufficient to compare the differences between these various implants. Therefore, in our study, we could not evaluate the difference according to the type of implant.
Thank you again for your collaboration.
9. Combined femoral and popliteal nerve block is superior to local periarticular infiltration anaesthesia for postoperative pain control after total knee arthroplasty
Schittek, G.A., Reinbacher, P., Rief, M. et al. Knee Surg Sports Traumatol Arthrosc (2022). https://doi.org/10.1007/s00167-022-06868-w
Query Letter to the Editor
Xue Gao, MD, Fu-Shan Xue, MD, Bin Hu, MD
By a randomised controlled trial including 50 patients who underwent total knee arthroplasty (TKA), Schittek et al demonstrated that when dexmedetomidine was added to local anaesthetic, combined femoral and popliteal nerve block (CFPNB) was superior to local periarticular infiltration anaesthesia (LIA) in terms of postoperative opioid-sparing and pain control. Given that the use of nonopioid or opioid–sparing multimodal analgesia protocol to improve postoperative pain control is being emphasized in current practice of Enhanced Recovery After Surgery (ERAS) protocols , their findings have potential implications. Other than the limitations described in discussion, however, there are several issues in method and results of this study that need further clarification and discussion.
First, regarding sample size evaluation, the authors stated that an oral milligram morphine equivalent (MME) of more than 10 mg required for postoperative pain control was considered a clinically meaningful difference in opioid consumption between the groups. However, they did not provide the literature evidence of this expected clinically meaningful difference. We would like to remind the readers that for patients undergoing TKA, the recommended minimal clinically important difference of MME required for postoperative pain control in available literature is an absolute reduction of 10 mg intravenous morphine in 24 h . Because 1 mg intravenous morphine is equivalent to 3 mg oral morphine , we argue that the use of more than 10 mg oral MME as the minimal clinically important difference to evaluate sample size in this study is not appropriate.
Second, opioid consumption during first 48 h after surgery is significantly higher in patients receiving LIA compared with patients receiving CFPNB. However, the authors did not provide the absolute differences of oral MME between the groups. According to the data provided in table 2 of Schittek et al’ article, maximum between-group difference of oral MME for 24 h (i.e., PACU + postoperative day 0) was 24, which is equivalent to 8 mg intravenous morphine . That is, maximum between-group difference in MME of opioid consumption does not excess the recommended minimal clinically
important difference, i.e., an absolute reduction of 10 mg intravenous morphine in the 24 h . Accordingly, we also question their ethical considerations to stop the study by using a difference of 15 mg oral MME between the groups.
Third, for patients undergoing TKA, the recommended minimal clinically important difference of postoperative pain score is 1.5 at rest state and 1.8 during motion on a 0-10 pain scale . In this study, maximum pain scores during motion in the PACU and maximum pain scores at rest and during motion on the first postoperative day were significantly higher in patients receiving LIA compared with patients receiving CFPNB. However, the authors did not provide the absolute between-group differences of maximum
pain scores at rest and during motion in each observed point, as performed in previous study comparing postoperative analgesic efficacy of different nerve blocks in patients undergoing TKA . Thus, it was unclear whether absolute between-group differences of maximum pain scores in the PACU and on the first postoperative day exceed the recommended minimal clinically important differences. Furthermore, a pain score of 3 or less is commonly considered as satisfied postoperative pain control . We noted that medians of maximum pain scores at rest and during motion in all observed points
postoperatively were 2 or less, indicating that most of patients receiving two interventions have a satisfied postoperative pain control. Unfortunately, this study did not assess and compare patient satisfaction with postoperative pain control. In this case, it is difficult for readers to determine whether improvement of postoperative pain control with CFPNB should be considered as being clinically important.
Finally, main goals of postoperative analgesia in patients undergoing TKA include minimising pain, improving the quaility of recovery and the functional outcomes to facilitate early ambulation and discharge . The design of this study included a 6–day postoperative observation, but it did not assess the quality outcomes of ERAS protocols for TKA, such as the range of keen motion, quadriceps strength, daily ambulation distance, time to first straight leg rise, quality of recovery, length of hospital stay and others [5–7]. In
fact, the quality outcomes of ERAS protocols are very important for determining efficacy and clinical availability of an intervention for postoperative pain control [2,8]. Because of this limitation, an important issue that cannot be answered in this study is whether both increased opioid–sparing and improved postoperative pain control by CFPNB compared
with LIA really can be translated into the clinical benefits of patient outcomes. We believe that this study would have provided more useful data regarding efficacy and clinical values of CFPNB for pain control after TKA, if the design had included the assessments on the quality outcomes of ERAS protocols.
1. Schittek GA, Reinbacher P, Rief M et al (2022) Combined femoral and popliteal nerve block is superior to local periarticular infiltration anaesthesia for postoperative pain control after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2022 Feb 3. https://doi.org/10.1007/s00167-022-06868-w
2. Mancel L, Van Loon K, Lopez AM (2021). Role of regional anesthesia in Enhanced Recovery After Surgery (ERAS) protocols. Curr Opin Anaesthesiol 2021; 34(5):616-25. https://doi.org/10.1097/ACO.0000000000001048
3. Laigaard J, Pedersen C, Rønsbo TN et al (2021) Minimal clinically important
differences in randomised clinical trials on pain management after total hip and knee arthroplasty: a systematic review. Br J Anaesth. 126:1029-1037.
4. Dowell D, Haegerich TM, Chou R (2016) CDC Guideline for Prescribing Opioids for Chronic Pain—United States, 2016. JAMA. 315:1624–1645. https://doi.org/ 10.1001/jama.2016.1464
5. Wang Q, Hu J, Zeng Y (2021) Efficacy of Two Unique Combinations of Nerve Blocks on Postoperative Pain and Functional Outcome After Total Knee Arthroplasty: A Prospective, Double–Blind, Randomized Controlled Study. J Arthroplasty. 36:3421–3431. https://doi.org/10.1016/j.arth.2021.05.014
6. Stevenson KL, Neuwirth AL, Sheth N (2018) Perioperative pain management
following total joint arthroplasty: A review and update to an institutional pain protocol. J Clin Orthop Trauma. 9:40–45. https://doi.org/10.1016/j.jcot.2017.09.014
7. Ochroch J, Qi V, Badiola I et al (2020) Analgesic efficacy of adding the IPACK block to a multimodal analgesia protocol for primary total knee arthroplasty. Reg Anesth Pain Med. 45:799–804. https://doi.org/10.1136/rapm–2020–101558
8. Cappiello G, Camarda L, Pulito G et al (2020) Continuous Femoral Catheter for Postoperative Analgesia After Total Knee Arthroplasty. Med Arch. 74:54–57. https://doi.org/10.5455/medarh.2020.74.54–57
Thank you very much for evaluating and discussing our manuscript. With respect to sample size calculation and power analysis, we clarify, that a total sample size of even 188 patients was calculated according to a clinically meaningful difference greater than 10 mg oral morphine equivalents (OME) for postoperative pain control. However, our ethics committee decided to have us perform a safety analysis after 50 cases. It is correct, that Laigaard et al.  present a minimal clinically important difference of milligram morphine equivalent (MME) of 10 mg intravenous morphine on pain management after total knee arthroplasty. However, according to our ethics committee, oral morphine equivalents were considered the clinical gold standard at our institution and our sample size was therefore sufficient to detect even more discreet differences between both groups accordingly, which is in line with level II studies by Jaremko et al. , Hungerford et al. , and Rambhia et al. , choosing less than 188 patients in each of their studies.
Second, it is correct, that our study was stopped due to a difference of 15mg OME between both groups, which was set 1.5-fold of the minimal clinically important difference according to our ethics committee. This was justified due to the high routine of our surgeons and patients´ satisfaction with the procedure.
Third, it is correct, that maximum pain scores during motion in the PACU and at rest and during motion on the first postoperative day were significantly higher in patients receiving LIA compared with patients receiving CFPNB and that we did not present absolute between-group differences of maximum pain scores as published by Wang et al. . However, as you stated, a pain score of 3 or less is commonly considered as satisfied postoperative pain control, which was not achieved in all patients of the LIA group enrolled in our study at the second day. Therefore, we observed an even stronger justification for stopping the study, as requested by our ethics committee.
Finally, it is correct that we presented no clinical data with respect to ERAS protocols , as our aim was solely to compare both anesthesiological procedures and clinical outcomes will be presented in a future manuscript. Additional clinical data such as range of motion (ROM), quadriceps strength, daily ambulation distance, time to first straight leg rise, and others are certainly important but would obviously not have altered the outcome or conclusion of our study, which was stopped after safety analysis of 50 patients. We agree that we could have added more data in our study. However, the conclusion of our work would be the same indicating superiority of combined femoral and popliteal nerve block over periarticluar infiltration anaesthesia for postoperative pain control after total knee arthroplasty.
1. Laigaard J, Pedersen C, Ronsbo TN et al (2021) Minimal clinically important differences in randomized clinical trials on pain management after total hip and knee arthroplasty: a systematic review. Br J Anaesth. 126:1029-1037.
2. Jaremko I, Lukasevic K, Tarasevicius S et al. (2021) Comparison of 2 peripheral nerve blocks techniques for functional recovery and postoperative pain management after total knee arthroplasty: a prospective, double-blinded, randomized trial. Med Sci Monit. 11;27:e932848.
3. Hungerford M, Neubauer P, Ciotola J et al. (2021) Liposomal Bupivacaine vs Ropivacaine for Adductor Canal Blocks in Total Knee Arthroplasty: A Prospective Randomized Trial. J Arthroplasty 36(12):3915-3921.
4. Rambhia M, Chen A, Kumar AH et al. (2021) Ultrasound-guided genicular nerve blocks following total knee arthroplasty: a randomized, double-blind, placebo-controlled trial. Reg Anesth Pain Med. 46(10):862-866.
5. Wang Q, Hu J, Zeng Y (2021) Efficacy of Two Unique Combinations of Nerve Blocks on Postoperative Pain and Functional Outcome After Total Knee Arthroplasty: a prospective, Double-Blind, Randomzied Controlled Study. J Arthroplasty. 36:3421-3431.
6. Stevenson KL, Neuwirth AL, Sheth N (2018) Perioperative pain management following total joint arthroplasty: A review and update to an institutional pain protocol. J Clin Orthop Trauma. 9:40-45.
10. The translated Danish version of the Western Ontario Meniscal Evaluation Tool (WOMET) is reliable and responsive
Clementsen, J.M., Skou, S.T., Hansen, S.L. et al.
Query Letter to the Editor
Christian Fugl Hansen1, Michael Rindom Krogsgaard
We have read the article by Clementsen et al.  with equal interest and anticipation. Unfortunately, we believe the paper states inappropriate conclusions based on low-level evidence and a flawed methodological approach. The promotion of the Danish version of WOMET as an appropriate outcome in trials on meniscal pathology on this basis is premature. The suggestion that KOOS4 is also a good outcome measure rests on a scientifically misconducted analysis and contradicts earlier robust psychometric analyses of KOOS.
First, the types of analyses that are carried out are insufficient to fulfill the aim of the study to cross-culturally adapt WOMET. Translation and cross-cultural adaptations of a PROM is a non-trivial process which includes proper translation, interviews with patients ensuring what is measured, and then thorough assessments of the psychometric properties testing how well this is measured by the translated questionnaire.
Valid PROMs possess a series of measurement properties, all of which are relevant, but not equally important. There is a hierarchy of importance :
- Content validity
- Structural validity, internal consistency, cross-cultural validity
- Reliability, criterion validity, hypotheses testing construct validity, responsiveness
The study by Clementsen et al. assesses the lowest ranking measurement properties: reliability, responsiveness, and criterion validity relative to KOOS4, which not a valid measurement outcome. The structural validity, internal consistency, and cross-cultural validity of WOMET are not assessed.
Second, the authors base their analyses on the assumption that domain scores can be aggregated to one score for both WOMET and KOOS4. This contrasts substantial evidence of the opposite: WOMET consists of three separate domains with separate summary scores . There is evidence that the measurement properties of WOMET are based on a 3-domain structure . The authors chose to analyze the total score of WOMET, which is the aggregated sum score of all three domains. This violates the important principle of unidimensionality within the construct of a scale and is simply invalid . This imperative principle also applies to KOOS4, which is the aggregated average score of four of the five domains of KOOS, and there is robust evidence of KOOS as a multidimensional structure with individual scores [1, 3, 7].
The use of aggregated scores unfortunately invalidates the majority of the study results. To compare invalid data with invalid data makes no sense. Figure 3 is a good example of the improvement that any questionnaire – adequate as inadequate – can show after treatment. Thus, the changes in the aggregated scores from WOMET and KOOS4 are unspecific and irrelevant to evaluate changes caused by treatment of meniscal problems. Therefore, the statement from the authors that “…the responsiveness of the WOMET and the KOOS4 score was found to be comparable with similar ES and changes in scores over time, which suggests that both questionnaires are equally good at assessing changes in outcome of meniscal surgery” is flawed, erroneously implying that KOOS4 and WOMET are equally adequate as outcomes for this patient group, while ignoring a number of more important measurement properties of WOMET.
WOMET is a promising and welcomed substitute for the less-adequate KOOS and IKDC for use as outcome measures in trials concerning meniscal pathology, due to a higher degree of content validity. Nevertheless, assessments of the factor structure (structural validity), internal consistency, and differential item functioning (DIF) for systematic cross-country bias (cross-cultural validity) must be carried out and confirmed to be adequate before the Danish version of WOMET can be regarded as a valid and reliable outcome measurement tool.
- Christensen KB, Comins JD, Krogsgaard MR, et al. (2020 ) Psychometric validation of PROM Article four in a series of ten. Scand J Med Sci Sports doi: 10.1111/sms.13908
- Clementsen JM, Skou ST, Hansen SL, et al. (2021) The translated Danish version of the Western Ontario Meniscal Evaluation Tool (WOMET) is reliable and Knee Surg Sports Traumatol Arthrosc;29(12):4278-85
- Comins J, Brodersen J, Krogsgaard M, et (2008) Rasch analysis of the Knee injury and Osteoarthritis Outcome Score (KOOS): a statistical re-evaluation. Scand J Med Sci Sports;18(3):336-45
- Ebrahimi N, Naghdi S, Ansari NN, et al. (2020)Statistical validity and reliability of the Persian version of the Western Ontario Meniscal Evaluation Tool (WOMET) according to the COSMIN BMC Musculoskelet Disord;21(1):183
- Kirkley A, Griffin S, Whelan (2007)The development and validation of a quality of life-measurement tool for patients with meniscal pathology: the Western Ontario Meniscal Evaluation Tool (WOMET). Clin J Sport Med;17(5):349-56
- Krogsgaard MR, Brodersen J, Christensen KB, et (2021) How to translate and locally adapt a PROM. Assessment of cross-cultural differential item functioning. Scand J Med Sci Sports;31(5):999-1008
- Prinsen CAC, Mokkink LB, Bouter LM, et al. (2018) COSMIN guideline for systematic reviews of patient-reported outcome Qual Life Res;27(5):1147-57 1798-3
- Zulkifli MM, Kadir AA, Elias A, et (2017) Psychometric Properties of the Malay Language Version Knee Injury and Osteoarthritis Outcome Score (KOOS) Questionnaire among Knee Osteoarthritis Patients: A Confirmatory Factor Analysis. Malays Orthop J;11(2):7-14.
Response from authors:
We appreciate the interest in our paper concerning the translation of the Western Ontario Meniscal Evaluation Tool (WOMET) from English to Danish.
As described in our paper  we used the well–established forward–backward translation approach totranslate the WOMET into Danish.  This included semi–structured cognitive debriefing interviews with patients with meniscal tears to ensure comprehensibility.
The WOMET was developed in 2007, has been in use for several years and has been translated into several languages. [3–9] The different aspects of validity of the WOMET have been examined in the original language and in several other languages during translation.3–9 Based on the available resources for our study and the work by previous authors on validation, we decided to focus on translation, reliability testing and responsiveness of the Danish version of the WOMET.
In our paper we present reliability data for all subscales and the total WOMET score aggregated as suggested by the original authors of the WOMET. 
When planning an RCT, a single primary outcome is typically preferred for statistical reasons. Patients with meniscal tears often report many different issues.  It can therefore be hard to determine what is the most important problem to evaluate as the primary outcome in a trial. Onesolution to this is to use an aggregate score of a patient reported outcome. However, to support the primary outcome, and to allow for clinical interpretation, the individual subscales should always be reported as secondary outcomes.
The Knee Injury and Osteoarthritis and Outcome Score (KOOS) is designed to investigate outcomes in patients in the continuum from knee injury to osteoarthritis,[11,12] and has been extensively tested for psychometric properties, and used in several trials on patients in this continuum. [13–16] However, it is not disease specific – that is, not designed specifically to patients with meniscal tears. Disease specific outcomes may therefore be more responsive in capturing change over time or after treatment than KOOS. In our study we therefore compared the responsiveness of the total WOMET score with the KOOS4 score (average score of 4 of the 5 KOOS subscales). We had expected that the WOMET score, designed specifically to patients with meniscal tears, would be more responsive to change over time than the KOOS4, but this was not the case.
Patient reported outcomes are rarely perfect, and continued examination and development of the psychometric properties is often an ongoing process, which is also the case for the WOMET. 
1. Clementsen JM, Skou ST, Hansen SL, et al. The translated Danish version of the Western Ontario Meniscal Evaluation Tool (WOMET) is reliable and responsive. Knee Surg Sports Traumatol Arthrosc. Dec 021;29(12):4278–4285. doi:10.1007/s00167–021–06551–6
2. Beaton DE, Bombardier C, Guillemin F, Ferraz MB. Guidelines for the process of cross–cultural adaptation of self–report measures. Spine (Phila Pa 1976). Dec 15 2000;25(24):3186–91. doi:10.1097/00007632–200012150–00014
3. Kirkley A, Griffin S, Whelan D. The development and validation of a quality of life–measurement tool for patients with meniscal pathology: the Western Ontario Meniscal Evaluation Tool (WOMET). Clin J Sport Med. Sep 2007;17(5):349–56. doi:10.1097/JSM.0b013e31814c3e15
4. Celik D, Demirel M, Kus G, Erdil M, Ozdincler AR. Translation, cross–cultural adaptation, reliability and validity of the Turkish version of the Western Ontario Meniscal Evaluation Tool (WOMET). Knee Surg Sports Traumatol Arthrosc. Mar 2015;23(3):816–25. doi:10.1007/s00167–013–2753–z
5. Ebrahimi N, Naghdi S, Ansari NN, Jalaie S, Salsabili N. Statistical validity and reliability of the Persian version of the Western Ontario Meniscal Evaluation Tool (WOMET) according to the COSMIN checklist. BMC Musculoskelet Disord. Mar 23 2020;21(1):183. doi:10.1186/s12891–020–3171–2
6. Sgroi M, Daxle M, Kocak S, Reichel H, Kappe T. Translation, validation, and cross–cultural adaption of the Western Ontario Meniscal Evaluation Tool (WOMET) into German. Knee Surg Sports Traumatol Arthrosc. Aug 2018;26(8):2332–2337. doi:10.1007/s00167–017–4535–5
7. Tong WW, Wang W, Xu WD. Development of a Chinese version of the Western Ontario Meniscal Evaluation Tool: cross–cultural adaptation and psychometric evaluation. J Orthop Surg Res. Aug 15 2016;11(1):90. doi:10.1186/s13018–016–0424–8
8. van der Wal RJP, Heemskerk BTJ, van Arkel ERA, Mokkink LB, Thomassen BJW. Translation and Validation of the Dutch Western Ontario Meniscal Evaluation Tool. J Knee Surg. May 2017;30(4):314–322. doi:10.1055/s–0036–1584576
9. Sihvonen R, Jarvela T, Aho H, Jarvinen TL. Validation of the Western Ontario Meniscal Evaluation Tool (WOMET) for patients with a degenerative meniscal tear: a meniscal pathology– specific quality–of–life index. J Bone Joint Surg Am. May 16 2012;94(10):e65. doi:10.2106/JBJS.K.00804
10. Skou ST, Pihl K, Nissen N, Jorgensen U, Thorlund JB. Patient–reported symptoms and changes up to 1 year after meniscal surgery. Acta Orthop. Jun 2018;89(3):336–344. doi:10.1080/17453674.2018.1447281
11. Roos EM, Roos HP, Ekdahl C, Lohmander LS. Knee injury and Osteoarthritis Outcome Score (KOOS)—validation of a Swedish version. ScandJMedSciSports. 1998;8(6):439–448.
12. Roos EM, Roos HP, Lohmander LS, Ekdahl C, Beynnon BD. Knee Injury and Osteoarthritis Outcome Score (KOOS)—development of a self–administered outcome measure. JOrthopSports PhysTher. 1998;28(2):88–96.
13. Frobell RB, Roos EM, Roos HP, Ranstam J, Lohmander LS. A randomized trial of treatment for acute anterior cruciate ligament tears. 363/4/331 pii ;10.1056/NEJMoa0907797 doi. NEnglJ Med. 2010;363(4):331–342.
14. Kise NJ, Risberg MA, Stensrud S, Ranstam J, Engebretsen L, Roos EM. Exercise therapy versus arthroscopic partial meniscectomy for degenerative meniscal tear in middle aged patients: randomised controlled trial with two year follow–up. BMJ. 2016;354:i3740. doi:10.1136/bmj.i3740
15. Skou ST, Roos EM, Laursen MB, et al. A Randomized, Controlled Trial of Total Knee Replacement. N Engl J Med. Oct 22 2015;373(17):1597–606. doi:10.1056/NEJMoa1505467
11. Acetabular retroversion does not affect outcome in primary hip arthroscopy for femoroacetabular impingement
Dippmann, C., Siersma, V., Overgaard, S. et al. Knee Surg Sports Traumatol Arthrosc (2022). https://doi.org/10.1007/s00167-022-06918-3
Query Letter to the Editor
Zaki Arshad, Vikas Khanduja
We read with great interest the article: “Acetabular retroversion does not affect outcome in primary hip arthroscopy for femoroacetabular impingement’ by Dippmann et al. published in Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA).
We appreciate the authors’ efforts to investigate the role of acetabular version on outcomes of hip arthroscopy for femoroacetabular version. This is a very important area of research, as highlighted by our recent systematic review, also published in KSSTA, which found that approximately one in three patients presenting with symptomatic FAI may show an abnormal acetabular version . However, we are concerned by some aspects of the study methodology, which are likely to influence the authors’ conclusion that there is no difference in outcomes between patients with and without acetabular retroversion.
The authors use the posterior wall sign (PWS) and ischial spine sign (ISS) to classify patients into two discrete groups: retroversion and no retroversion. Whilst these signs may be effective in defining hips as retroverted or not, this classification gives no indication as to the extent of acetabular retroversion, with both groups likely containing a broad range of version values. This may mask differences in outcome which could exist between patients with varying degrees of retroversion. For example, Fabricant et al found that patients with femoral version < 5o showed inferior outcomes compared to those with version of 5o – 20o and >200, highlighting the importance of assessing retroversion using a continuous, rather than categorical grouping metholdogy . We appreciate that such an approach requires CT data which may not be available in national databases such as that used in Dippmann et al . Furthermore, as the authors describe, the PWS and ISS have relatively low inter-rater reliability . Given that the study data is derived from 16 different institutions, this is very likely to impact the separation of patients into the aforementioned groups. Together, the lack of a numerical acetabular version measurement, along with the low inter-rater reliability of radiographic signs, limits the extent to which the authors’ assertion that acetabular retroversion does not affect outcomes can be definitively concluded.
From a clinical perspective, orthopaedic surgeons are interested in understanding the influence of morphological parameters such as acetabular version on arthroscopic outcomes, to aid the management of patient expectations and clinical decision making with regards to the need for operative correction of these parameters, through procedures such as periacetabular osteotomy. The study of Dippmann et al assesses one parameter in isolation, however, readers should be aware that there may be an interaction between multiple hip morphological parameters and hence these should be studied together. Research suggests that a compensatory relationship many exist between acetabular and femoral version, whereby the effect of acetabular retroversion, may be mitigated through the development of femoral anteversion, helping to avoid abutment of the femoral neck and acetabular rim . Without an understanding of the distribution of femoral version values, it is entirely possible that the results reported by Dippman et al are influenced by such compensation of acetabular retroversion . We therefore suggest that clinicians should take a holistic approach to the characterisation and study of rotational deformities, considering the effect of multiple parameters collectively. Such an approach has been described by the work of Bouma et al, which combines femoral and acetabular version with femoral neck shaft angle, alpha angle and lateral centre edge angle, into a single parameter labelled the omega zone .
- Arshad Z, Maughan HD, Sunil Kumar KH, Pettit M, Arora A, Khanduja V (2021) Over one third of patients with symptomatic femoroacetabular impingement display femoral or acetabular version abnormalities. Knee Surgery, Sport Traumatol Arthrosc 29:2825–2836
- Bouma HW, Hogervorst T, Audenaert E, Krekel P, van Kampen PM (2015) Can combining femoral and acetabular morphology parameters improve the characterization of femoroacetabular impingement? Clin Orthop Relat Res United States 473:1396–1403
- Buller LT, Rosneck J, Monaco FM, Butler R, Smith T, Barsoum WK (2012) Relationship between proximal femoral and acetabular alignment in normal hip joints using 3-dimensional computed tomography. Am J Sports Med 40:367–375
- Dippmann C, Siersma V, Overgaard S, Krogsgaard MR (2022) Acetabular retroversion does not affect outcome in primary hip arthroscopy for femoroacetabular impingement. Knee Surgery, Sport Traumatol Arthrosc htpps:/doi.org/10.1007/s00167-022-06918-3
- Fabricant PD, Fields KG, Taylor SA, Magennis E, Bedi A, Kelly BT (2015) The effect of femoral and acetabular version on clinical outcomes after arthroscopic femoroacetabular impingement surgery. J. Bone Jt. Surg 97:537-543
- Kappe T, Kocak T, Neuerburg C, Lippacher S, Bieger R, Reichel H (2011) Reliability of radiographic signs for acetabular retroversion. Int Orthop 35:817–821
Response from authors:
Thank you for the comments regarding our article “Acetabular retroversion (AR) does not affect outcome in primary hip arthroscopy for femoroacetabular impingement” . We agree that the treatment principles of non-arthritic hip pain are developing as the importance of the various anatomical pathologies becomes clear from evidence. So far, there is not one single pathology that has been identified as most important to treat in patients with hip pain. To identify the cause of hip pain is therefore challenging and usually more a rule-out, than a rule-in task.
Our study focuses of retroversion, which is only one aspect of hip pathology.
The comment states that using PWS and ISS to identify retroversion gives no indication as to the extent of acetabular retroversion. We disagree with this, as a more severe retroversion shows as a larger posterior wall sign. However, in our study the degree of retroversion has not been considered, and we agree that this is a limitation of the study. As we point out, the most severe cases have probably been treated with PAO.
The gold standard to diagnose osseous hip/pelvic pathologies is a standard pelvic x-ray . Not only can all major hip/pelvis deformities such as developmental dysplasia of the hip (DDH), osteoarthritis (OA), cam/pincer deformity, pediatric/adolescent hip deformities, etc. be identified, but a pelvic x-ray is cheap and readily available. The strength of our study is that the patient population covers a whole country and is not selected, which would be the case if CT-data were also required, as CT-scan is not used routinely in patients considered for hip arthroscopy. We agree that femoral torsion is not considered in our material. However, it was not the aim of the study.
The influence of femoral version on the outcome after hip preserving surgery has still to be confirmed. Kunze et al. did not find any difference in outcome comparing patients with different degrees of femoral version . Similar finding where reported by other groups [2, 3, 5]. However, establishment of cut-off values for treatment of femoral is a subject for future research.
It is possible that we use a definition of AR (pos. posterior wall sign and pos. ischial spine sign) that is broader than a definition that would use CT-scans with a high threshold. Tentatively, this may include various patients in our definition of AR who would not have AR in a narrower definition. In doing so, the differences in outcome would be estimated conservatively. As the effect sizes are invariably very small, this means that either the number of consequential AR is negligible, or AR also in a narrow definition has no impact on the treatment outcome. Anyway, we have no structurally collected CT-scan data and the signs are used in Danish hospitals to define AR, which makes this project close to practice.
We do not consider the participation of 16 different centers as a limitation, as our material includes all institutions that offer hip arthroscopy in Denmark. This is much more representative than materials covering a single institution or a single surgeon. Also, the study uses a validated outcome measure (Hip and Groin Outcome Score, HAGOS) for these patients, which is often not the case in other studies.
We have not adjusted for center in our analyses (which could have been done by e.g. a random effect in our models). However, this could have affected the width of the confidence intervals (they would tentatively be narrower) but not the estimates of average outcome. Since the differences in mean outcomes are invariably small, we believe that our conclusion is not affected by not taking clustering into centers into account.
All institutions in Denmark offering hip preserving surgery have agreed to follow a diagnostic algorithm based on the standard pelvic x-ray. The idea is that patients with articular hip pain are referred to the institution, which is most likely able to offer the most relevant treatment (fig. 1). However, before offering surgery for global acetabular retroversion or DDH surgeons are usually adding further imaging, including CT and MR scans. The cohort in the current study does not include all patients in Denmark with radiological signs of acetabular retroversion, but only patients who underwent arthroscopic treatment. As we have explained in the article, this is a limitation of the study.
We agree to the suggestion that a “holistic approach” should be used, when diagnosing hip pain. For instance, clinical examination determines if there is a suspicion of retroversion of the femoral neck. The considerations regarding a possible connection between acetabular retroversion and femoral anteversion are very interesting and the clinical effect will be relevant to study. Until such evidence is available we believe that the concept of “primum non nocere” (first, do no harm) is important and underlines that the clinical effect of invasive treatment strategies should be demonstrated before they are implemented in the daily routine.
Fig. 1. : Triage algorithm for patients’ suspect of joint related hip pain using a standardized pelvis x-ray as it has been formally approved on a national consensus meeting in 2016. As certain surgical procedures as PAO and hip arthroscopy exclusively can be treated at a limited number of highly specialized orthopedic departments agreeing on specific referral criteria, increases the chance that Danish patients will be seen at a department most likely to be responsible for the entire treatment. However, this algorithm is solely a guide for the referral of a patient. Patients with radiologic signs of AR may still receive a hip arthroscopy.
- Dippmann C, Siersma V, Overgaard S, Krogsgaard MR. Acetabular retroversiondoes not affect outcome in primary hip arthroscopy for femoroacetabular impingement. Knee Surg Sports Traumatol Arthrosc. 2022 Feb 28.
- Ferro FP, Ho CP, Briggs KK, Philippon MJ. Patient-centered outcomes after hip arthroscopy for femoroacetabular impingement and labral tears are not different in patients with normal, high, low femoral version. Arthroscopy. 2015;31(3):454-459.
- Jackson TJ, Lindner D, El-Bitar YF, Domb BG. Effect of femoral anteversion on clinical outcomes after hip arthroscopy. Arthroscopy. 2015;31(1):35-41.
- Kunze K, Alter T, Alexander C et al. Association Between Orientation and Magnitude of Femoral Torsion and Propensity for Clinically Meaningful Improvement After Hip Arthroscopy for Femoroacetabular Impingement Syndrome A Computed Tomography Analysis The American Journal of Sports Medicine 2021;49(9):2466–2474
- Lall AC, Battaglia MR, Maldonado DR, et al. Does femoral retroversion adversely affect outcomes after hip arthroscopy for femoroacetabular impingement syndrome? A midterm analysis. Arthroscopy. 2019;35(11):3035-3046
- Tannast M, Siebenrock KA, Anderson SE. (2007) Femoroacetabular impingement: radiographic diagnosis–what the radiologist should know. Am J Roentgenol 188(6):1540-52.
12. Intra-articular injection receipt within 3 months prior to primary total knee arthroplasty is associated with increased periprosthetic joint infection risk
Avila, A., Acuña, A.J., Do, M.T. et al. Knee Surg Sports Traumatol Arthrosc (2022). https://doi.org/10.1007/s00167-022-06942-3
Query Letter to the Editor
Jérôme Grondin, MD, Pierre Menu, MD, Marc Dauty, MD and Alban Fouasson-Chailloux, MD, PhD.
We read with interest the paper of Avila et al. (1) evaluating the influence of pre-operative intra-articular injections on the occurrence of periprosthetic joint infections (PJI) after primary total knee arthroplasty (TKA) in 12 studies. Each study was evaluated according to the Methodological Index for Non-Randomized Studies (MINORS), which is an instrument designed to assess the methodological quality of non-randomized surgical studies, including 12 items (2). Yet, from our perspective, the prospective study by Grondin et al. (3) was inadequately scored , which underestimated the value of their results. Indeed, using the score defined in MINORS criteria, we consider that this study deserved a higher score, as defined below:
- “Adequate control group”: this study was scored “0”, whereas it provided proofs of having a gold standard diagnostic test (International Consensus Meeting on Periprosthetic Joint Infections (4)) and therefore matches MINORS statement.
- “Contemporary groups”: this criteria states that control and studied group should be managed during the same time period (no historical comparison) (2). In this study, which is a cohort study, all patients were equally followed between January 2016 to June 2019 (3). Hence, this criteria should be scored 2.
- “Baseline equivalence of groups”: this study was scored “0”. It is a cohort study, and therefore patients exposed and non-exposed belong to the same population. Confounding factors can bias the interpretation of results, that is why an analysis was performed regarding every previously reported potential confounding factors, and subgroup analyses were performed if a confusion bias was highlighted. In this study “sex” variable was found to be a potential confounding factor, that is why analyses were performed regarding “male” and “female” patients separately. In our perspective, baseline equivalence of groups was adequately assessed in this study.
- “Adequate statistical analysis”: statistics were in accordance with the design of the study, as confidence intervals and Odds ratios were provided.
Inadequate assessment of methodological quality of studies may interfere with the calculations of the overall pooled-effect of pre-operative intra-articular injection in PJI incidence in this meta-analysis, and in the interpretation of the results, which may have consequences in clinical practice.
- Avila A, Acuña AJ, Do MT, Samuel LT, Kamath AF. Intra-articular injection receipt within 3 months prior to primary total knee arthroplasty is associated with increased periprosthetic joint infection risk. Knee Surg Sports Traumatol Arthrosc (2022). https://doi.org/10.1007/s00167-022-06942-3
- Slim K, Nini E, Forestier D, Kwiatkowski F, Panis Y, Chipponi J. (2003) Methodological index for non-randomized studies (minors): development and validation of a new instrument. Anz J Surg [accessed May 2022]: https://www.scinapse.io
- Grondin J, Menu P, Métayer B, Crenn V, Dauty M, Fouasson-Chailloux A. (2021) Intra-Articular Injections Prior to Total Knee Arthroplasty Do Not Increase the Risk of Periprosthetic Joint Infection: A Prospective Cohort Study. Antibiotics: 10(3):330.
- Shohat N, Bauer T, Buttaro M, Budhiparama N, Cashman J, Della Valle CJ, et al. (2019) Hip and Knee Section, What is the Definition of a Periprosthetic Joint Infection (PJI) of the Knee and the Hip? Can the Same Criteria be Used for Both Joints?: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty: 34(2, Supplement):S325‑7.
Response from authors:
We thank Grondin et al. for their thoughtful letter regarding our recent meta-analysis exploring the relationship between pre-operative intra-articular injections and post-operative periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) . We believe that their evaluation of their 2021 prospective cohort study with the Methodological Index for Non-Randomized Studies (MINORS) scoring system raises important points regarding the current state of literature exploring this topic as well as its respective limitations  .
As noted in our analysis, a large majority of studies evaluating this relationship are retrospective and have inadequate control groups. Similarly, there is large heterogeneity in the utilized PJI diagnosis criteria as well as the evaluated intra-articular injection type and formulation. To that regard, we applaud Grondin et al. for conducting one of the few prospective studies evaluating the impact of preoperative injections on PJI rates. However, we additionally reiterate the need for the segregation of hyaluronic acid (HA) and corticosteroid (CSI) injection cohorts in future analyses. Similarly, there remains a need for appropriate matching in studies comparing injection and non-injection cohorts to ensure that baseline PJI risk does not confound reported results.
Based on the authors’ MINORS scoring, their analysis would receive a score between 20 and 22 and thus make it one of the highest scores among studies included in our systematic review. However, it is important to note that this change does not affect the results of the pooled analysis, subgroup analyses, or sensitivity analyses performed to address the heterogeneity of the data. Specifically, our pooled analyses were not based on the quality of each analysis and thus our finding that injections provided within the 3-month pre-operative period were associated with an increased incidence of PJI remains unchanged.
We thank the authors again for helping clarify how they would have scored their prospective analyses and further emphasizing the need for appropriate methodological considerations in future analyses exploring this association.
13. Autologous semitendinosus tendon graft could function as a meniscal transplant
Rönnblad, E., Rotzius, P. & Eriksson, K. Knee Surg Sports Traumatol Arthrosc 30, 1520–1526 (2022)
Query Letter to the Editor
Angelo V. Vasiliadis, Nikolaos E. Koukoulias
We have read with great interest the recent published article entitled “Autologous semitendinosus tendon graft could function as a meniscal transplant” by Rönnblad et al. . Firstly, we would like to congratulate the authors for this interesting technical report on the use of an autologous semitendinosus tendon graft that could function as a meniscal transplant. In a 12-month follow-up period, they provide a second-look arthroscopy and functional outcomes of seven patients undergoing this surgical procedure. These findings demonstrate the promising potential of the meniscal transplant, which can survive, revascularize and remodel to a wedge-shaped meniscus-like structure. The use of an autograft tendon as a meniscal transplant would enable restoration of knee biomechanics, improve clinical outcomes, overcome graft size-matching, allografts availability and ethical issues, while minimizing costs.
The use of semitendinosus tendon autograft has been previously evaluated as a meniscus replacement. Based on animal studies and human reports, tendon autografts were recognized as a promising substitution in meniscus reconstruction, with the potential to differentiate into a meniscus-like tissue over the time [2-5]. However, Johnson and Feagin, did not observe any difference in mechanical integrity, conversion into fibrocartilage tissue or preservation of the joint compartment . Other investigators reported that meniscus replacement with quadriceps tendon was inferior to cryopreserved meniscal allografts and that was associated with increasing degenerative changes of the knee joint . However, a careful evaluation of these studies reveals limitations in trial design, including patients with valgus knee and a previous surgical history of anterior cruciate ligament reconstruction. Additional studies with more stringent inclusion criteria are warranted.
Despite the limited number of published studies evaluating surgical techniques and the possibility of an autologous tendon graft to substitute a meniscus deficit, Rönnblad et al. , attempt to optimize the outcomes by providing a more detailed and easily reproducible surgical technique. Specifically, the grafts varied between 12 and 15 cm in length and between 6 and 7 mm in diameter. Selecting the optimal graft size is fundamental to achieve a successful surgical outcome. Failure to congruously match the patient’s graft size to patient’s tibial plateau anatomy can lead to altered tibiofemoral contact pressures and early failure of the graft. More commonly, three-dimensionally (3D) reconstructed computed-tomography (CT) is used pre-operatively, in order to calculate the dimension of the tibial plateau curvature and ensure graft size accurate selection intra-operatively. It would be interesting to know how was this match achieved in the present study and whether there were any alternatives which could be easily reproduced intra-operatively in case of a mismatch between the graft and the tibial plateau anatomy.
The firm attachment at its insertion sites and peripheral fixation of the autologous tendon graft as a meniscal transplant warrants further evaluation, since it can have a significant impact on the graft integration and function. Traditionally, peripheral fixation is achieved using a combination of all-inside, inside-out and outside-in sutures, while fixation of the roots may be achieved either by using suture buttons through tibial bone tunnels, knotless anchors or interference screws. In the present technical study, the investigators reported the use of vertical sutures around the graft in order to stabilize the semitendinosus autograft . However, in order to easily reproduce this technique, additional details about the characteristics of sutures (size, absorbable or non-absorbable, monofilament or multifilament, natural or synthetic and the number of sutures placed around the periphery to the capsule) need to be reported. Additionally, the suture configuration (single- or double-row, vertical mattress or cross-stitch suture technique) on the graft-capsular surface is also critical for reproducing this technique.
To date, augmentation techniques in meniscal repair surgery show promising results on functional outcomes and emerge as an encouraging treatment option to promote healing in soft tissue injuries [8,9]. The application of biological augmentation of the autograft, using platelet-rich plasma, stem cells, fibrin clot or/and microfractures, may be beneficial in clinical practice. Therefore, it would be interesting to know whether any augmentation technique was used in the study to increase the viability of the autograft and accelerate the healing progress within the capsule.
In conclusion, the authors described an appealing technique on the use of semitendinosus tendon as a meniscal transplant. Larger studies with longer post-operative follow-up period focusing on selected populations assessing fixation methods are warranted. We would like to thank the authors for their motivated technical report and we hope their study will promote further research on this field.
- Rönnblad E, Rotzius P, Eriksson K (2022) Autologous semitendinosus tendon graft could function as a meniscal transplant. Knee Surg Sports Traumatol Arthrosc 30:1520-1526
- Mora G, Alarez E, Ripalda P, Forriol F (2003) Articular Cartilage Degeneration after frozen meniscus and achilles tendon allograft transplantation: Experimental study in sheep. Arthroscopy 19(8):833-841
- Li C, Hu X, Meng Q, Zhang X, Zhu J, Dai L, et al (2017) The potential of using semitendinosus tendon as autograft in rabbit meniscus reconstruction. Sci Rep 7:7033
- Milenin O, Strafun S, Sergienko R, Baranov K (2020) Lateral meniscus replacement using peroneus longus tendon autograft. Arthrosc Tech 9(8):e1163-e1169
- Ishikawa H, Okamura H, Ohno T, Fujita S, Akezuma H, Inagaki K (2022) Arthroscopic medial meniscus posterior root reconstruction and pull-out repair combined technique for root tear of medial meniscus. Arthrosc Tech 11(2):e109-e114
- Johnson LL, Feagin JA (2000) Autogenous tendon graft substitution for absent knee joint meniscus: A pilot study. Arthroscopy 16(2): 191-196
- Pressel T, Lewinski G, Kohn D, Wirth CJ (2005) Meniscus replacement with quadriceps tendon – A long-term analysis. Z Orthop Ihre Grenzgeb 143(1):42-47
- Haunschild ED, Huddleston HP, Chahla J, Gilat R, Cole BJ, Yanke AB (2020) Platelet-rish plasma augmentation in meniscal repair surgery: A systematic review of comparative studies. Arthroscopy 36(6):1765-1774
- Bozkurt M (2022) Lateral meniscus allograft transplantation in combination with BMAC (bone marrow aspirate concentrate) injection: Biologic Augmentation of the allograft. Arthrosc Tech 11(5):e767-e77
Response from the authors:
We want to start by thanking Dr Vasiliadis and Dr Koukoulias for their thoughtful commentary to our publication entitled “Autologous semitendinosus tendon graft could function as a meniscal transplant” . We are pleased to find the appreciation of our suggested surgical technique as being detailed and reproducible.
It is true that the size matching of a meniscus transplant is crucial, especially when using allograft transplantation. Any mismatch could lead to altered tibiofemoral contact pressures. The surgical technique used in our publication does however provide a graft length that was in all cases longer than needed. The use of tibial bone-tunnels and pull-out technique assures that the accurate intraarticular meniscus graft length could be obtain and any excess
could be placed in the tunnels.
The peripheral attachment is of great importance. There are several different suturing techniques that can be applied depending on location and desired orientation of the suture configuration. In our study an all-inside device was used for the posterior horn. For the inside-out fixation of the mid-body part as well as for the outside-in fixation of the anterior horn a 2.0 fiberwire was used. The 2.0 fiberwire is a multistrand polyethylene suture. The number of sutures used vary depending on the length of the graft and between a total of nine
to twelve were used. The sutures were placed in a vertical hay-stack orientation to grasp as many of the circumferential fibers as possible.
The field of orthobiologics is of great interest and as mentioned there are some promising results in using biological augmentation when conducting meniscal repairs. In our country, however, the use of platelet-rich plasma, stem cells or fibrin clots et cetera is still relatively uncommon in association to meniscal repair. In combination with the lack of strong
scientific evidence we choose not to apply any biological facilitation of healing.
14. The morphology of the femoral footprint of the anterior cruciate ligament changes with aging from a large semicircular shape to a small flat ribbon-like shape
The morphology of the femoral footprint of the anterior cruciate ligament changes with aging from a large semicircular shape to a small flat ribbon-like shape
Morales-Avalos, R., Perelli, S., Vilchez-Cavazos, F. et al. Knee Surg Sports Traumatol Arthrosc (2022). https://doi.org/10.1007/s00167-022-06935-2
Query Letter to the Editor
The article published by Morales-Avalos et al was read with great interest: “The morphology of the femoral footprint of the anterior cruciate ligament changes with aging from a large semicircular shape to a small flat ribbon‑ like shape”.
We commend the authors of the article for their novel idea and its future application, although it would be interesting to raise a few pertinent points related to the study.
In the Materials & Methods section, they refer that it was not possible to discern the distribution in two fascicles in all the knees, specifying later in the results sections that this occurred in 8 of the 45 specimens older than 50 years. Therefore, 36 specimens under 50 years of age would actually be compared with 37 specimens over 50 years of age, being the total number of 72 knees and not 81 knees.
Furthermore, they establish the cut-off point of the different groups of knee specimens at 50 years, but when dividing the average age of these groups, they observe that it would be 87 ± 8.3 years in the group of men over 50 years and 82 ± 9.2 years in the group of women over 50 years of age, and 28 ± 6.2 years in the group of men under 50 years and 26 ± 7.4 years in the group of women under 50 years of age. Perhaps, it would be more accurate to indicate that the knee lesions in the second or third decade are being compared with those in the eighth or ninth decade.
The findings obtained from a sample of knee specimens with a mean age of 85-87 years should not be representative for population strata between 50 – 60 years, so they should be cautious when extrapolating these findings and modify the surgical management of the anterior cruciate ligamentoplasty in this last population stratum based on these data. Even more, ligamentoplasty
is not an optimal technique to be performed on an 80-year-old knee, opting for a total knee arthroplasty as the treatment of choice in this population stratum [1-3].
As the authors of this article mention in their limitations, increasing the sample size implies a greater power of the study, hence reducing the probability of a Beta error [4,5]. However, making multiple comparisons also carries a higher risk of making an Alpha error [4,6]. None the less, the fact that they have carried out such a detailed anatomical study of 81 different specimens is truly admirable. This is astonishing and we congratulate them.
1. Kuperman E.F., Schweizer M., Joy P., Gu X., Fang M.M.: The effects of advanced age on primary total knee arthroplasty: a meta-analysis and systematic review. BMC Geriatr 2016;16: pp. 41
2. Maempel J.F., Riddoch F., Calleja N., Brenkel I.J.: Longer hospital stay, more
complications, and increased mortality but substantially improved function after knee replacement in older patients. Acta Orthop 2015; 86: pp. 451-456.
3. Parvizi J., Nunley R.M., Berend K.R., Lombardi A.V., Ruh E.L., Clohisy J.C., et. al.: High level of residual symptoms in young patients after total knee arthroplasty. Clin Orthop Relat Res 2014; 472: pp. 133-137.
4. Rao UK. Concepts in sample size determination. Indian J Dent Res. 2012 Sep-Oct;23(5):660-4. Brown CG, Kelen GD, Ashton JJ, Werman HA.
5. The beta error and sample size determination in clinical trials in emergency medicine. Ann Emerg Med. 1987 Feb;16(2):183-7. Mascha EJ, Vetter TR.
6. Significance, Errors, Power, and Sample Size: The Blocking and Tackling of Statistics. Anesth Analg. 2018 Feb;126(2):691-698
Response from authors:
We have read the comments of Dr Torres-Pérez on our paper entitled “The morphology of the femoral footprint of the anterior cruciate ligament changes with aging from a large semi-circular shape to a small flat ribbon-like shape” with interest. We would like to thank the interest shown in our investigation by these colleagues and the criticisms made with the aim of further improving the understanding of our paper.
We will proceed to respond to your points or concerns. In some corpses of those of advanced age, it was impossible to precisely distinguish between both ACL bundles, meaning that we could not clearly split it into two bundles in some of our dissections. However, those few specimens in which the two bundles could not be distinguished were indeed used for the morphological classification as well as for the morphometry analyses whenever it did not involve bundle differentiation. It was clearly stated in our article. If Dr Torres-Perez and Dr Jayant Wadhwani did not understand this point, we apologize for not making it clear.
With regards to the second comment, 50 years was not a cut-off point. It was just an arbitrarily chosen border between youth and old age. The objective of the work was to determine whether morphological changes in the ACL femoral attachment occur simply due to the aging process. We were not comparing knee injuries by different decades. In fact, the current work is based on anatomical (normal) changes. As is well understood in anthropometry, the further apart the means the more objective and easier to extrapolate the results will be.
As for the third comment, we did not aim to draw any categorical conclusion from the present work. We would rather like to raise a hand against drawing solid conclusions based on a series of aged cadavers that can push the orthopedic community to change a common practice, namely the ACL reconstruction. The results showed that, regardless of gender, the femoral ACL femoral attachment has a semi-circular morphology in young individuals, as has been previously described. However, this morphology becomes ribbon-like with aging. It is likely due to the resorption or senescence of the PL bundle.
- Śmigielski R, Zdanowicz U, Drwięga M, et al. Ribbon like appearance of the midsubstance fibres of the anterior cruciate ligament close to its femoral insertion site: A cadaveric study including 111 knees. Knee Surg Sports Traumatol Arthrosc 2015;23:3143–3150.
- Siebold R, Schuhmacher P, Fernandez F, et al. Flat midsubstance of the anterior cruciate ligament with tibial “C”-shaped insertion site. Knee Surg Sports TraumatolArthrosc 2015;23:3136–3142.
15. Increased medial meniscus extrusion led to worse clinical outcomes after medial opening‐wedge high tibial osteotomy
Lee, CH., Yang, HY. & Seon, JK. Knee Surg Sports Traumatol Arthrosc (2022). https://doi.org/10.1007/s00167-022-07148-3
Query Letter to the Editor
Goksel Dikmen, Kerim Sariyilmaz, Vahit Emre Ozden
We read with great interest the article by Lee et al, “Increased medial meniscus extrusion led to worse clinical outcomes after medial opening‐ wedge high tibial osteotomy” about clinical and radiological improvement of medial meniscus extrusion (MME) after medial opening-wedge high tibial osteotomy (MOWHTO). 
Follow-up comprised 79 patients (80 knee) who underwent MOWHTO. MME
subgroups analysis was evaluated pre- and postoperatively with magnetic resonance imaging. However, we were surprised to find that medial meniscus posterior root tear (MMPRT) was not evaluated or discussed. If any patient had MMPRT before high tibial osteotomy, radiological measurements of MME might be changed in pathological (MME) subgroup and authors should include MMPRT to the exclusion criteria of the study to showing MEE improvement in knees in varus alignment without MMPRT.
MMPRT are defined radial tear of meniscal attachment or a bony avulsion. Medial meniscus posterior root is essential for maintaining meniscal hoop tension effect and preventing meniscal extrusion. It was widely known that MMPRT have strong association with MME. MME was significantly greater in knees with varus alignment and sometimes coexists with MMPRT even in knees with neutral alignment.[3, 4] Kim et al. evaluated MME patients who underwent MOWHTO with arthroscopic MMPRT repair and preoperatively 3.0 ± 0.7 mm and postoperatively 3.1 ± 0.7 mm. Itou et al reported favorable clinical results in patients with MMPRT, and moderate varus knee alignment treated by MOWHTO with arthroscopic repair allinside root repair.
In conclusion, we congratulate Lee et al for their work, but we believe that their
conclusion about patients with a postoperative pathologic MME of > 3 mm had inferior clinical outcomes after MOWHTO when compared with those with a postoperative non-pathologic MME of ≤ 3 mm is not supported by sufficient information about MMPRT.
1. Lee CH, Yang HY, Seon JK. Increased medial meniscus extrusion led to
worse clinical outcomes after medial opening-wedge high tibial
osteotomy. Knee Surg Sports Traumatol Arthrosc 2022.
2. Pache S, Aman ZS, Kennedy M, Nakama GY, Moatshe G, Ziegler C, et al.
Meniscal Root Tears: Current Concepts Review. Arch Bone Jt Surg
3. Sung JH, Ha JK, Lee DW, Seo WY, Kim JG. Meniscal extrusion and
spontaneous osteonecrosis with root tear of medial meniscus:
comparison with horizontal tear. Arthroscopy 2013;29(4):726-32.
4. Lee DH, Lee BS, Kim JM, Yang KS, Cha EJ, Park JH, et al. Predictors of
degenerative medial meniscus extrusion: radial component and knee
osteoarthritis. Knee Surg Sports Traumatol Arthrosc 2011;19(2):222-9.
5. Kim YM, Joo YB, Lee WY, Kim YK. Remodified Mason-Allen suture
technique concomitant with high tibial osteotomy for medial meniscus
posterior root tears improved the healing of the repaired root and
suppressed osteoarthritis progression. Knee Surg Sports Traumatol
6. Itou J, Kuwashima U, Itoh M, Okazaki K. High tibial osteotomy for medial
meniscus posterior root tears in knees with moderate varus alignment
can achieve favorable clinical outcomes. J Exp Orthop 2022;9(1):65.
Response from the authors:
We thank our colleagues for their thoughtful comments on our paper.
In our study, only 5 out of 80 cases had a medial meniscus posterior root tear (MMPRT). The reason for the low incidence of MMPRT is probably because we included only those who had MRI after plate removal surgery. The degree of MMPRT was minimal, so only partial meniscectomies were performed without repair for MMPRT. Because the number of cases was small, it was difficult to show the difference between the groups with and without MMPRT. In multivariate analysis, the MMPRT did not show significant results for medial meniscus extrusion (MME) improvement and clinical outcomes.
MMPRT has a strong association with MME. Kim et al. reported that MMPRT is the most relevant predictor of meniscal extrusion. On the other hand, Nha et al. reported that 50% of patients showed complete healing and 30% showed incomplete healing of medial meniscus root tear after high tibial osteotomy without meniscal procedures.  Although this study did not directly compare the extent of root tear healing with the measurement of MME, this result can be partly explained by reduction in contact pressure after high tibial osteotomy. Therefore, I think our study sheds meaningful light on the relationship between postoperative MME and clinical outcomes after medial opening-wedge high tibial osteotomy.
Once again, we truly appreciate your valuable comments.
1. Sung JH, Ha JK, Lee DW, Seo WY, Kim JG. Meniscal extrusion and spontaneous osteonecrosis with root tear of medial meniscus: comparison with horizontal tear. Arthroscopy 2013;29(4):726-32.
2. Kim MS, Koh IJ, Kim CK, Choi KY, Kang KH, In Y (2020) Preoperative medial meniscal extrusion is associated with patient-reported outcomes after medial opening wedge high tibial osteotomy. Am J Sports Med 48:2376-2386
3. Nha KW, Lee YS, Hwang DH, Kwon JH, Chae DJ, Park YJ, Kim JI. Second-look arthroscopic findings after open-wedge high tibia osteotomy focusing on the posterior root tears of the medial meniscus. Arthroscopy. 2013;29(2):226-231.
16. Bicruciate-retaining total knee arthroplasty non-inferior to posterior-stabilized prostheses after 5 years: a randomized, controlled trial
Lavoie, F., Denis, A., Chergui, S. et al. Knee Surg Sports Traumatol Arthrosc (2022). https://doi.org/10.1007/s00167-022-07210-0
Query Letter to the Editor
We have read the recently published article, entitled “Bicruciate‑ retaining total knee arthroplasty non‑ inferior to posterior‑ stabilized prostheses after years: a randomized, controlled trial” by Lavoie et al.  with great interest. They randomly assigned patients underwent total knee arthroplasty (TKA) to bicruciate‑ retaining (BCR) group or posterior‑ stabilized (PS) group, and compared postoperative pain score that was specified as primary outcome in the trial registry. However, we have some concerns regarding the discrepancy between the title of the article and the results of the randomized controlled trial.
In this study, the primary outcome was compared using the Student’s t-test to
analyze whether the calculated p-value was > 0.05 or not. Student’s t-test showed that p values were > 0.05 at all measurements. Needless to say, in case of the p-value was < 0.05, there was a statistically significant difference between the BCR-TKA and PS-TKA groups. And, in case of p-value was > 0.05, there was no difference. However, it is incorrect to assume that no difference means that the two groups are non-inferior . P value can prove whether there is a difference or not, but p-value cannot prove non inferiority. The use of p-values to demonstrate non-inferiority is prohibited, and confidence intervals must be used to demonstrate non-inferiority .
The hypothesis of this randomized controlled trial was that the BCR-TKA would result in better clinical scores than PS-TKA. The hypothesis indicates that this study was a typical two-arm superiority trial, i.e., a trial to compare two groups to determine which intervention would be superior. The sample size calculation was also based on the hypothesis to analyze the superiority. They set 15 points were minimum clinically important difference of the primary outcome and calculated more than 28 patients per group to detect a mean difference and standard deviation of 15 ± 14 points with a 5% significance level and 80% power. When sample size calculations were performed for a non-inferiority study as indicated in the title, the concept and calculation must be completely different from those of a superiority study . If authors intended to show the non-inferiority, they should determine the non-inferior margin before starting the trial, and confirm whether the boundary of the 95% confidence interval for the between-group difference would not excess the non-inferiority margin.
At the end of this letter, we would like to emphasize that research topic of the
randomized controlled trial by Lavoie et al. is of special interest in the field of adult knee reconstruction surgery. Recognizing the importance of the topic, we felt it necessary to call attention to the title, which could mislead readers in the interpretation of study results.
1. Lavoie F, Denis A, Chergui S, Al-Shakfa F, Sabouret P (2022) Bicruciate-retaining total knee arthroplasty non-inferior to posterior-stabilized prostheses after 5 years: a randomized, controlled trial. Knee Surg Sports Traumatol Arthrosc https//doi: 10.1007/s00167-022-07210-0.
2. Boutron I, Dutton S, Ravaud P, Altman DG (2010) No difference Reporting and interpretation of randomized controlled trials with statistically nonsignificant results for primary outcomes. JAMA 303:2058-64
3. Mauri L, D’Agostino RB Sr (2017) Challenges in the Design and Interpretation of Noninferiority Trials. N Engl J Med 377:1357-67
Response from the authors:
We thank Dr Tsukada for the constructive feedback on our manuscript.
We recognise that the term “non-inferior” would be inaccurate if used to describe the statistical methods of our original study, as Dr Tsukada rightly pointed out. However, the mention of “non-inferior” in the title should not be interpreted as a statistical inference, but rather as a general term shedding light on the equivalence of clinical outcomes compared to the posterior-stabilized prostheses group. Other terms that could have been used include “similar”, “comparable”, or “analogous”.
In fact, the title was changed from “Bicruciate-retaining total knee arthroplasty yields similar outcomes but more complications compared to posterior-stabilized prostheses after 5 years: A Randomized Controlled Trial” to the current version during the revision process as reviewers recommended to opt for a more succinct title.
We are nonetheless confident the usage of “non-inferior” will not mislead readers as a detailed description of the analyses and results is provided in the abstract in addition to the manuscript.
Again, we are grateful for the constructive feedback, and we are pleased to see that the manuscript generates interest from readers on a subject which we believe warrants more attention from the scientific community.