Association of Jump-Landing Biomechanics With Tibiofemoral Articular Cartilage Composition 12 Months After ACL Reconstruction

Background: Excessively high joint loading during dynamic movements may negatively influence articular cartilage health and contribute to the development of posttraumatic osteoarthritis after anterior cruciate ligament reconstruction (ACLR). Little is known regarding the link between aberrant jump-landing biomechanics and articular cartilage health after ACLR. Purpose/Hypothesis: The purpose of this study was to determine the associations between jump-landing biomechanics and tibiofemoral articular cartilage composition measured using T1 rho magnetic resonance imaging (MRI) relaxation times 12 months postoperatively. We hypothesized that individuals who demonstrate alterations in jump-landing biomechanics, commonly observed after ACLR, would have longer T1 rho MRI relaxation times (longer T1 rho relaxation times associated with less proteoglycan density). Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 27 individuals with unilateral ACLR participated in this cross-sectional study. Jump-landing biomechanics (peak vertical ground-reaction force [vGRF], peak internal knee extension moment [KEM], peak internal knee adduction moment [KAM]) and T1 rho MRI were collected 12 months postoperatively. Mean T1 rho relaxation times for the entire weightbearing medial femoral condyle, lateral femoral condyle (global LFC), medial tibial condyle, and lateral tibial condyle (global LTC) were calculated bilaterally. Global regions of interest were further subsectioned into posterior, central, and anterior regions of interest. All T1 rho relaxation times in the ACLR limb were normalized to the uninjured contralateral limb. Linear regressions were used to determine associations between T1 rho relaxation times and biomechanics after accounting for meniscal/chondral injury. Results: Lower ACLR limb KEM was associated with longer T1 rho relaxation times for the global LTC (Delta R (2) = 0.24; P = .02), posterior LTC (Delta R (2) = 0.21; P = .03), and anterior LTC (Delta R (2) = 0.18; P = .04). Greater ACLR limb peak vGRF was associated with longer T1 rho relaxation times for the global LFC (Delta R (2) = 0.20; P = .02) and central LFC (Delta R (2) = 0.15; P = .05). Peak KAM was not associated with T1 rho outcomes. Conclusion: At 12 months postoperatively, lower peak KEM and greater peak vGRF during jump landing were related to longer T1 rho relaxation times, suggesting worse articular cartilage composition.

Automated summary

This study found that lower peak KEM and greater peak vGRF during jump landing were associated with longer T1 rho relaxation times at 12 months postoperatively, suggesting worse articular cartilage composition.