The fickle ACL deficient athlete: Investigation of the non-coper response to injury, surgery, and neuromuscular training

Background. Anterior cruciate ligament (ACL) injuries are the most prevalent sports-related knee injury and are estimated to affect up to 250,000 athletes in the United States every year. Gait abnormalities, quadriceps strength deficits, knee joint effusion, and limited range of motion are ubiquitous acutely after ACL rupture and often persist following ACL reconstruction. Early identification of those athletes at risk for poor outcomes after surgery can assist rehabilitation specialists in tailoring the most efficacious treatment protocol for this group.;Purpose. The goal of this work was to identify and intervene with noncopers that may be more likely to require additional rehabilitation in order to achieve normal neuromuscular strategies after surgery and meet their return to sport goals. Unilateral stance mechanics were used to evaluate whether pre-operative neuromuscular intervention changes single limb positioning strategies. We also compared the differences between the clinical performance and gait variables of ACL-deficient males and females before and after ACL reconstruction. To further investigate the restoration of function after surgery, the effects of a post-operative neuromuscular intervention are described.;Methods. The effects of injury, neuromuscular training, and ACL reconstruction were examined on male and female non-copers during (1) a unilateral stance task and walking gait using current motion analysis techniques and (2) clinical performance tests. Non-copers from a larger randomized controlled trial underwent each of the testing procedures before and after pre-operative physical therapy, and 6 months after ACL reconstruction. The same walking gait biomechanics and clinical performance measures were evaluated on ten additional non-copers who received post-operative perturbation training.;Significance. The information gathered during this investigation adds to our understanding of non-copers in two distinct ways: (1) women were identified as a uniquely functioning group of non-copers and (2) the timing of neuromuscular training appears to affect the recovery process in a subgroup of non-copers. Biomechanical changes found in response to rehabilitation further suggest the malleability and diversity of this group of ACL-deficient athletes. By evaluating gender-specific responses to ACL injury, intervention, and surgery, we have defined important neuromuscular differences within the non-coper cohort that may be effectively addressed by tailored physical therapy intervention. This body of work provides a foundation for future research to investigate the effects of different neuromuscular treatments on the recovery of function in athletes who sustain ACL injuries.