Abstract
BACKGROUND: Reinjury rates and suboptimal outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR) may be influenced by reduced psychological readiness to return to sport (RTS) and asymmetries in quadriceps strength and jump-landing biomechanics. HYPOTHESES: ACL-Return to Sport after injury (ACL-RSI) scores, quadriceps performance, and jump landing biomechanics would be significantly associated; the ACLR group would show lower ACL-RSI scores, lower quadriceps peak torque (QuadPT) and rate of torque development (RTD), and different peak knee abduction and extension angles/moments compared with healthy controls; and those with high quadriceps function would have significantly greater ACL-RSI scores than healthy controls. STUDY DESIGN: Case-control. LEVEL OF EVIDENCE: Level 3. METHODS: Military academy cadets cleared for full sports participation after ACLR were compared with matched healthy controls. Psychological readiness was assessed using the ACL-RSI scale. Quadriceps performance was measured by QuadPT and RTD, both expressed as limb symmetry indices (LSIs). Jump-landing biomechanics were analyzed via 3-D motion capture, focusing on peak knee abduction angle/moment LSI and peak knee flexion angle/moment LSI. Pearson's correlations assessed relationships among time since surgery, psychological readiness, quadriceps performance, and biomechanics. RESULTS: This study included 35 participants after ACLR (mean time since surgery, 19.2 ± 9.6 months) and 22 healthy controls. In the ACLR group, ACL-RSI scores were correlated strongly with QuadPT LSI (r = 0.64) and RTD LSI (r = 0.55). No significant correlations were found between the ACL-RSI and jump-landing biomechanics. Participants after ACLR had significantly lower ACL-RSI scores and greater frontal plane biomechanical differences than controls. CONCLUSION: Psychological readiness was related to quadriceps performance but not with jump-landing biomechanics. Participants after ACLR exhibited lower psychological readiness and altered frontal plane biomechanics compared with healthy controls. CLINICAL RELEVANCE: Sports medicine clinicians should address reduced psychological readiness to RTS and jump landing biomechanics symmetry in patients recovering from ACLR.