Reaction force patterns of injured and uninjured knees during walking and pivoting

A precise knowledge of the biomechanical alterations produced by anterior cruciate ligament (ACL) damage would aid in selecting appropriate therapeutic intervention and monitoring rehabilitation. In an attempt to assess dynamic knee joint function, we compared the ground reaction force (GRF) and vertical couple patterns during walking and pivoting from an ACL-deficient population with those from a separate uninjured population. Statistical methods were used to quantitate the differences between the two populations for each force pattern in each functional task and to delineate the intervals of the force patterns in each functional task during which significant differences existed between the two populations. Our results indicate that significant differences exist between the GRF and vertical couple patterns of ACL-deficient subjects and uninjured subjects, but that onset and duration of these differences during stance phase vary among force components and tasks. The processing scheme extracts significant differences in the GRF and vertical couple patterns that would be lost in a comparison of a few pattern descriptors. Our results suggest that the vertical couple should be evaluated during assessment of pivoting maneuvers and show promise of providing useful information for assessment of knee dysfunction.