Contralateral limb foot rotation during unilateral toe-in or toe-out walking in people with knee osteoarthritis

•Unilateral foot rotation results in small changes in the contralateral limb.•Mixed disease presentation between knees may require maintenance of baseline values.•These findings have implications for gait modification in knee osteoarthritis. Gait modification is a treatment approach often used for a variety of neuromuscular and musculoskeletal pathologies. Gait modification is commonly applied to a single limb, as is done with foot rotation (FR) in people with knee osteoarthritis (KOA). However, the extent to which gait changes observed in the trained limb are also exhibited in the untrained, contralateral limb during a training session is unknown. The purpose of this study was to examine the within-limb FR differences across four unilateral FR modifications compared to natural walking. Sixteen individuals with KOA walked on a treadmill while performing four different FR conditions: 10° toe-in, 0°, 10° toe-out and 20° toe-out. Motion capture was conducted to track FR magnitude after five minutes of practice. The change in contralateral FR angle compared to natural walking significantly increased during toe-in 10° walking (3.1°) compared to toe-out −10° and −20° walking (−1.2° and −1.5°, respectively). As expected, the ipsilateral FR angle was significantly different between all conditions. These results suggest that small, but statistically significant changes in the untrained contralateral limb FR are observed during FR training of the ipsilateral limb. This may indicate a desire for symmetry, or a compensation when modifying the ipsilateral limb. Therefore, clinicians may need to maintain baseline FR magnitudes in the untrained limb when a patient exhibits unilateral KOA characteristics or lateral compartment KOA.