The athlete who suffers an torn anterior cruciate ligament (ACL) will in all likelihood be advised to have ligament reconstruction surgery. The majority of ACL reconstruction surgeries will successfully restore the knee’s stability, but post-surgical outcomes remain quite variable. Less than half of athletes who have the operation will be able to return to their sport within the first year after surgery (despite some widely praised athletes who return within only a few months after surgery).
In addition, current estimates are that between 20% and 25% of athletes who have ACL reconstructive surgery will have a second knee injury. The outcomes of a second reconstruction are considerably less satisfactory than the outcomes after the primary reconstruction. Current surgical practices have greatly improved graft reconstruction and fixation techniques to consistently restore passive joint stability to the knee’s pre-injury level, yet successful return to sport after ACL reconstruction seems to be based on numerous postsurgical factors.
Importantly, that second ACL injury is strongly related to modifiable postsurgical risk factors such as biomechanical abnormalities and movement asymmetries, which are far more prevalent in this twice injured cohort than previously considered. Abnormalities and asymmetries can persist despite excellent functional performance but still are strongly associated with secondary injury incidence. Poor neuromuscular control and high-risk movement mechanics (heavily influenced by abnormal trunk and lower extremity movement patterns), raise both the risk of the first knee injury risk but also the risk of re-injury. Abnormal movement mechanics and neuromuscular control are no doubt residual to, and worsened by, the initial injury.
Evidence-based medicine dictates that research is needed to develop effective, effective interventions that improve these identified impairments so that athletes may experience a safe return to high-risk activity. The authors are imploring a paradigm shift in rehabilitation focus and techniques as well as in objective criteria for return-to-sport training that focus on resolving neuromuscular deficits that consistently persist after current reconstruction and rehabilitation techniques.