OBJECTIVE:To compare knee angles and moments between the injured and contralateral knee in participants with anterior cruciate ligament reconstruction, and compared with uninjured controls while navigating steps. DESIGN:Cross-sectional study. SETTING:University laboratory-based study. PARTICIPANTS:Twenty-five participants (30.8 ± 9.7 years; 13 women) with anterior cruciate ligament reconstruction (2-10 years post-surgery), and 24 controls (31.0 ± 10 years, 13 women). MAIN OUTCOME MEASURES:Three-dimensional motion analysis was used to record peak knee angles and external moments during step ascent and descent in three planes, along with spatiotemporal variables. RESULTS:During step ascent, the reconstructed knee exhibited significantly: (1) lower peak flexion angles compared to the controls (P = 0.005); (2) lower flexion moments (P < 0.001) compared to contralateral side and controls. No significant differences were found in the frontal and transverse planes between groups and sides. During step descent, no significant differences in angles and moments were found. CONCLUSIONS:Side-to-side asymmetries and lower knee flexion angles and external knee flexion moments were evident in participants with anterior cruciate ligament reconstruction and compared to controls. These findings suggest that incomplete recovery and compensatory or protective changes in neuromuscular control and joint function may persist 2-10 years post-surgery.