Decreased Knee Joint Loading Associated With Early Knee Osteoarthritis After Anterior Cruciate Ligament Injury

Abstract

Background Anterior cruciate ligament (ACL) injury predisposes individuals to early-onset knee joint osteoarthritis (OA). Abnormal joint loading is apparent after ACL injury and reconstruction. The relationship between altered joint biomechanics and the development of knee OA is unknown. Hypothesis Altered knee joint kinetics and medial compartment contact forces initially after injury and reconstruction are associated with radiographic knee OA 5 years after reconstruction. Study Design Case-control study; Level of evidence, 3. Methods Individuals with acute, unilateral ACL injury completed gait analysis before (baseline) and after (posttraining) preoperative rehabilitation and at 6 months, 1 year, and 2 years after reconstruction. Surface electromyographic and knee biomechanical data served as inputs to an electromyographically driven musculoskeletal model to estimate knee joint contact forces. Patients completed radiographic testing 5 years after reconstruction. Differences in knee joint kinetics and contact forces were compared between patients with and those without radiographic knee OA. Results Patients with OA walked with greater frontal plane interlimb differences than those without OA (nonOA) at baseline (peak knee adduction moment difference: 0.00 ± 0.08 N·m/kg·m [nonOA] vs −0.15 ± 0.09 N·m/kg·m [OA], P = .014; peak knee adduction moment impulse difference: −0.001 ± 0.032 N·m·s/kg·m [nonOA] vs −0.048 ± 0.031 N·m·s/kg·m [OA], P = .042). The involved limb knee adduction moment impulse of the group with osteoarthritis was also lower than that of the group without osteoarthritis at baseline (0.087 ± 0.023 N·m·s/kg·m [nonOA] vs 0.049 ± 0.018 N·m·s/kg·m [OA], P = .023). Significant group differences were absent at posttraining but reemerged 6 months after reconstruction (peak knee adduction moment difference: 0.02 ± 0.04 N·m/kg·m [nonOA] vs −0.06 ± 0.11 N·m/kg·m [OA], P = .043). In addition, the OA group walked with lower peak medial compartment contact forces of the involved limb than did the group without OA at 6 months (2.89 ± 0.52 body weight [nonOA] vs 2.10 ± 0.69 body weight [OA], P = .036). Conclusion Patients who had radiographic knee OA 5 years after ACL reconstruction walked with lower knee adduction moments and medial compartment joint contact forces than did those patients without OA early after injury and reconstruction.

Report of the Primary Outcomes for Gait Mechanics in Men of the ACL-SPORTS Trial: Secondary Prevention With and Without Perturbation Training Does Not Restore Gait Symmetry in Men 1 or 2 Years After ACL Reconstruction

“…Movement asymmetries during walking are prevalent after ACL injury and reconstruction and may increase the risk of posttraumatic osteoarthritis (OA) early after ACLR [6,41]. Previous research has found that a specialized type of neuromuscular training (ie, perturbation training) improves gait asymmetries and functional outcomes when applied to ACL-deficient patients [8,10,13,15,20].…”

“…However, because we randomized our subjects to treatment group, the findings should be more generalizable across surgical intervention. Finally, we did not analyze electromyographic data or use musculoskeletal modeling [5,29] to estimate joint contact forces, which have implications for the development of OA [27,41]. Further analysis is warranted.…”

“…After anterior cruciate ligament (ACL) injury, many individuals undergo reconstructive surgery to restore knee stability and function [30,38], yet despite ACL reconstruction (ACLR), movement asymmetries exist at least 6 months to 1 year after ACLR [12,16,19,20,36,41,43] and may persist longer [36]. Movement asymmetries during gait are associated with the development of early osteoarthritis [4,41]; thus, developing strategies to mitigate these asymmetries is an important area of research.…”

“…Movement asymmetries during gait are associated with the development of early osteoarthritis [4,41]; thus, developing strategies to mitigate these asymmetries is an important area of research.…”

“…Unfortunately, improvements in gait asymmetry that occur from preoperative perturbation training are not retained postoperatively [16,36]. Postoperative interventions beyond traditional physical therapy are likely needed to restore gait symmetry after ACLR given the prevalence of movement abnormalities that persist [6,16,27,28,36,37,40,41].…”