Greater Step Widths Reduce Internal Knee Abduction Moments in Medial Compartment Knee Osteoarthritis Patients During Stair Ascent.

Increased step widths have been shown to reduce peak internal knee abduction moments in healthy individuals but not in knee osteoarthritis patients during stair descent. This study aimed to assess effects of increased step widths on peak knee abduction moments and associated variables in adults with medial knee osteoarthritis and healthy older adults during stair ascent. Thirteen healthy older adults and 13 medial knee osteoarthritis patients performed stair ascent using preferred, wide, and wider step widths. Three-dimensional kinematics and ground reaction forces (GRFs) using an instrumented staircase were collected. Increased step width reduced first and second peak knee abduction moments, and knee abduction moment impulse. In addition, frontal plane GRF at time of first and second peak knee abduction moment and lateral trunk lean at time of first peak knee abduction moment were reduced with increased step width during stair ascent in both groups. Knee abduction moment variables were not different between knee osteoarthritis patients and healthy controls. Our findings suggest that increasing step width may be an effective simple gait alteration to reduce knee abduction moment variables in both knee osteoarthritis and healthy adults during stair ascent. However, long term effects of increasing step width during stair ascent in knee osteoarthritis and healthy adults remain unknown.