Active feedback gait retraining alters foot pressure patterns and reduces knee adduction moment in an anterior cruciate ligament reconstructed population

Anterior cruciate ligament (ACL) tear greatly accelerates osteoarthritis (OA) onset, and ACL reconstruction (ACLR) surgery has not been shown to prevent premature knee OA. It was recently shown that ACLR subjects with higher knee adduction moments (KAM) 2 years after ACLR had worse patient-reported outcomes at 8 years after surgery, and patients with higher relative contribution ofKAM to the total loading at the knee joint had greater decreases in medial-to-lateral femoral cartilage thickness ratios over time. As such, interventions such as gait retraining to reduce the KAM in ACLR patients present an opportunity to reduce the risk of developing premature knee OA. The purpose of this study was to test the efficacy ofa gait retraining method using active feedback to change the KAM by sensing lateral foot pressure and retraining to produce a medial weight transfer at the foot. Specifically, we hypothesized (1) there would be significant changes in foot pressure patterns (average heel pressure ratio) and joint loading (first peak KAM, KAM Impulse) with active feedback, (2) joint loading change is influenced by pressure threshold feedback setting (Level 1 vs. Level 2), and (3) joint loading is correlated with pressure distribution at the foot during walking.