Knee biomechanics during walking in recurrent lateral patellar dislocation are normalized by 1 year after medial patellofemoral ligament reconstruction

Abstract Purpose Gait kinematics and kinetics of the knee before and after medial patellofemoral ligament (MPFL) reconstruction in patients with recurrent lateral patellar dislocation (RPD) are unknown. The purpose of this study was to measure knee kinematics and kinetics during gait before and 1 year after anatomical MPFL reconstruction in patients with RPD and compare the results to healthy individuals. Methods Eleven RPD patients were treated using an anatomical MPFL reconstruction procedure. Gait analysis was conducted before and at 3, 6, and 12 months after surgery. For comparison, 15 healthy volunteers with no history of orthopaedic problems in their lower limbs were included as the control group. Knee kinematics and kinetics were analysed during gait. Results Before surgery, the internal knee extension moment in RPD patients was significantly lower than in controls ( P = 0.025). At 3 months post‐operatively, there was an additional decrease in knee extension moment compared to before surgery, and so it was still significantly lower than in the control group ( P < 0.01). One year post‐operatively, knee extension moment in the RPD group was significantly increased compared to 3 months post‐operatively ( P < 0.01). The knee flexion angle in the early stance phase in the RPD group at 3 months post‐operatively was significantly lower than that of controls ( P < 0.01). Knee kinematics and kinetics were similar to that of controls 1 year after surgery. Conclusion Initially, RPD patients had lower knee extension moments during gait compared with controls, but by 1 year after MPFL reconstruction, knee kinematics and kinetics of gait in the RPD patients had returned to normal. These observations indicate that MPFL reconstruction may help to delay prospective knee OA as long as possible by restoring the conformation of the patellofemoral joint and gait biomechanics by surgery.