Dynamic versus radiographic alignment in relation to medial knee loading in symptomatic osteoarthritis

Dynamic knee alignment is speculated to have a stronger relationship to medial knee loading than radiographic alignment. Therefore, we aimed to determine what frontal plane knee kinematic variable correlated most strongly to the knee adduction moment. That variable was then compared with radiographic alignment as a predictor of the knee adduction moment. Therefore, 55 subjects with medial knee OA underwent three-dimensional gait analysis. A subset of 21 subjects also underwent full-limb radiographic assessment for knee alignment. Correlations and regression analyses were performed to assess the relationships between the kinematic, kinetic and radiographic findings. Peak knee adduction angle most strongly correlated to the knee adduction moment of the kinematic variables. In comparison with radiographic alignment, peak knee adduction angle was the stronger predictor. Given that most epidemiological studies on knee OA use radiographic alignment in an attempt to understand progression, these results are meaningful.