To investigate effects of foot progression angle (FPA) modification on the first and second peaks of external knee adduction moment (EKAM) and knee adduction angular impulse (KAAI) in individuals with and without medial knee osteoarthritis (OA) during level walking.
PubMed, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, and SPORTDiscus were searched from inception to February 2020 by 2 independent reviewers. Included studies compared FPA modification (toe-in or toe-out gait) interventions to lower EKAM and/or KAAI with natural walking. Studies were required to report the first or second peaks of EKAM or KAAI.
Sixteen studies were included, and >85% of included patients were graded with Kellgren/Lawrence grade II-IV knee OA. Toe-in gait reduced the first EKAM peak (standardized mean difference [SMD] -0.75 [95% confidence interval (95% CI) -1.05, -0.45]) and KAAI (SMD -0.46 [95% CI -0.86, -0.07]), while toe-out gait reduced the second EKAM peak (SMD -1.04 [95% CI -1.34, -0.75]) in healthy individuals. For patients with knee OA, toe-out gait reduced the second EKAM peak (SMD -0.53 [95% CI -0.75, -0.31]) and KAAI (SMD -0.26 [95% CI -0.49, -0.03]), while toe-in gait did not affect both EKAM peaks and KAAI.
Discrepancy in biomechanical effects of FPA modification was demonstrated between individuals with and without medial knee OA. Compared with natural walking, both toe-in and toe-out gait may be more effective in lowering EKAM and KAAI in healthy individuals. Toe-out gait may reduce EKAM and KAAI in patients with mild-to-severe knee OA. There is insufficient data from patients with early-stage knee OA, indicating that future research is required.