Control of Knee Frontal Plane Moment via Modulation of Center of Pressure: A Prospective Gait Analysis Study

Abstract

Objectives: Footwear-generated biomechanical manipulations (e.g., wedge insoles) have been shown to reduce the magnitude of adduction moment about the knee. The theory behind wedged insoles is that a more laterally shifted location of the center of pressure causes a smaller distance of the moment arm of the knee joint adduction moment during gait. However, the relationship between the center of pressure and the knee adduction moment remains to be determined. The aim of this study was to assess the effect of the location of the center of pressure and the magnitude of the knee adduction moment during gait in healthy men. Methods: A novel foot-worn biomechanical device which allows controlled manipulation of the center of pressure location was utilized. Successive gait analysis testing was performed on 12 healthy men under four different conditions: control, neutral sagittal axis, center of pressure shifted medially and laterally from the functional sagittal axis. Results: The knee adduction moment during the stance phase significantly correlated with the shift of the center of pressure from the functional neutral sagittal axis in the frontal plane (i.e., from medial to lateral). The moment was reduced with the lateral sagittal axis configuration and augmented with the medial sagittal axis configuration. Conclusions: The study results confirm the hypothesis of a direct correlation between the coronal position of the biomechanical elements (location of the center of pressure) and the coronal kinetics of the knee.