Leading article of February 2018

ACL-reconstructed and ACL-deficient individuals show
differentiated trunk, hip, and knee kinematics during vertical hops
more than 20 years post-injury


Markström JL, Tengman E, Häger CK

Rupture of the anterior cruciate ligament (ACL) is very common in sports and often occurs in non-contact situations with full weight-bearing on one leg and with multi-plane knee loadings. It is important to determine the consequences of ACL injury and in particular the influence on movement strategies in the longer term to fully understand the impact of an injury. However, the few studies that have investigated kinematics in the long term so far present contradictory results.

Using a 3D motion capture system, we recorded the one-leg vertical hop performed by 66 persons tested on average 23 years after unilateral ACL injury, and 33 age- and sex-matched healthy-knee controls. The patients consisted of two cohorts treated with either, 1) surgery and physiotherapy, or 2) solely physiotherapy. Trunk, hip, and knee kinematics were investigated using multivariate methods to provide comprehensive information of movement strategies.

Our results showed that both ACL-injured groups presented different kinematics when compared to controls, although persons treated only with physiotherapy presented larger deviations. We also found different kinematics between treatment groups, and asymmetry between legs for both treatment groups which was not found for controls. In our article, we discuss the possibility of different protective strategies for the injured groups, and the importance of looking beyond the knee joint for this population. This study therefore adds knowledge about long-term consequences on movement patterns following ACL injury which crucially combines the trunk, hip, and knee. Consideration is also given to the two commonly used types of treatment i.e., reconstructive surgery in combination with physiotherapy or solely physiotherapy, as at present there is no concrete evidence as to which is best in the long term.