Letters to the editor

Please send your letter or proposal to the editors at kssta@esska.org.

ONLY those letters deemed to have scientific impact will be requested to be submitted via the Editorial Manager. These will be officially published online and in print along with the responses.

Others will be treated as communication or exchange between authors and only be published online on the KSSTA website with the title of the article in question, the query and the responses. These will not appear in the print issues and will have no DOIs.

Isolated Type II SLAP Tears Undergo Reoperation More Frequently

DeFazio MW, Özkan S, Wagner ER, Warner JJP, Chen NC. Isolated type II SLAP tears undergo reoperation more frequently. 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

Dear Editor,

We have read the paper “Isolated type II SLAP tears undergo reoperation more 6frequently” by DeFazio, M. W., Özkan, S.,et al. published in Knee Surgery, Sports Traumatology, Arthroscopy(2021) with great interest[3].

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[1]. 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 [5]In general, diagnostic 28modalities used to establish suspicion of a SLAP-lesion vary from 1) history taking [5], 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 [5], and4) confirmation by an MR arthrogram [8].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” [3],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.


  1. Arnold KF, Davies V, Kamps M de, Tennant PWG, Mbotwa J, Gilthorpe MS (2020) Reflections on modern methods: generalized linear models for prognosis and intervention—theory, practice and implications for machine learning. Int J Epidemiol 49:dyaa049
  2. Bhatnagar A, Bhonsle S, Mehta S (2016) Correlation between MRI and Arthroscopy in Diagnosis of Shoulder Pathology. J Clin Diagnostic Res 10:RC18-21
  3. 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
  4. 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
  5. Familiari F, Huri G, Simonetta R, McFarland EG (2019) SLAP lesions: current controversies. Efort Open Rev 4:25–32
  6. 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
  7. Hegedus EJ, Goode AP, Cook CE, Michener L, Myer CA, Myer DM, Wright AA (2012) Which physical examination tests provide clinicians with the most value when examining the shoulder? Update of a systematic review with meta-analysis of individual tests. Brit J Sport Med 46:964

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.

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

Dear Editor,

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 [3]. 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 [1]. 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 [4]. 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.


  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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 [1]. 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 [2].

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.


  1. 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
  2. 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.