Pre-surgery knee joint loading patterns during walking predict the presence and severity of anterior knee pain after total knee arthroplasty.

This study tested if abnormal sagittal knee joint loading patterns after total knee arthroplasty (TKA) were present pre-surgery, and if patterns with higher external knee flexion moments were related to the presence and severity of post-surgery anterior knee pain. Gait analysis and clinical evaluation were performed on 34 patients (41 arthroplasties) both before and 12-18 months after TKA, and on 20 healthy age-matched controls at matched velocities. The majority of knees with abnormal flexor or extensor sagittal knee joint loading patterns post-surgery (18 of 26, 69%) also displayed these patterns pre-surgery. Knee joint loading in the early mid-stance phase of walking prior to surgery was identified by stepwise regression as a significant predictor of the presence (exp(beta)=2.9, CI: 1.2-6.8, p=0.017) and severity of post-surgery anterior knee pain (R2=0.314, p=0.019). Therefore, the frequency and severity of anterior knee pain after TKA can be partially explained by retained pre-surgery gait patterns that had higher external flexion moments in the early mid-stance phase, which place higher forces on the patellofemoral joint.