Side-to-Side Differences in Dynamic Tibiofemoral Movement and Velocity Patterns Between ACL-Reconstructed and Contralateral Knees During Jump-Landing Tasks at Midterm Follow-up

Abstract

After anterior cruciate ligament (ACL) reconstruction (ACLR), graft failure rates are high, return-to-sport rates remain low, and, compared with nonoperative treatment, the incidence of posttraumatic osteoarthritis is not reduced. These findings suggest that ACLR may be unable to fully restore knee stability in dynamic situations when muscle activity and knee loading are present. To compare dynamic tibiofemoral movement and velocity patterns—specified as dynamic anterior tibial translation (ATTd) and internal tibial rotation (ITRd) movement and velocity—across the landing of jumping tasks between ACL-reconstructed and contralateral knees in patients with primary unilateral ACLR at midterm follow-up. Descriptive laboratory study. Patients who underwent primary ACLR were included from a previous randomized controlled trial and were prospectively assessed for additional analyses. Outcome measures included ATTd, ITRd, ATTd-velocity, and ITRd-velocity during the landing phase of the single-leg hop for distance (SLHD) and side hop (SH), measured with 3D optoelectronic motion capture. Secondary outcome measures included dynamic knee flexion, valgus angle and angular velocity patterns, and peak and time-to-peak vertical and posterior ground reaction forces (GRFs). For time-series data, statistical parametric mapping paired t tests were conducted. A total of 30 patients were included at midterm follow-up (4.7 ± 1.8 years post-ACLR). Patients exhibited significantly greater ATTd in ACL-reconstructed knees compared with contralateral knees during the landing of the SLHD (mean ± SD maximum difference = 2.7 ± 4.0 mm; P = .047; d = 0.69) and the SH (mean ± SD maximum difference = 3.8 ± 5.6 mm; P = .046; d = 0.67). Furthermore, patients exhibited significantly lower ITRd-velocity in ACL-reconstructed knees compared with contralateral knees during the landing of the SH (mean ± SD maximum difference = −0.07 ± 0.07 deg/ms; P = .03; d = 0.98). Patients with unilateral primary ACLR demonstrated side-to-side asymmetries in dynamic tibiofemoral movements and velocities during jump-landing tasks at midterm follow-up despite symmetry in jumping distance, knee flexion and valgus angles, and GRF. These findings warrant further investigation regarding their association with ACL strain, reinjury risk, and osteoarthritis development. Return-to-sport assessments that consider only jumping distance, flexion and valgus angles, and/or GRF may not capture all biomechanical asymmetries potentially contributing to ACL reinjury, highlighting the potential value for more accessible methods to assess or predict dynamic tibiofemoral movements.