Supinated Foot Posture Is Associated With Reduced Knee and Foot Function in Patients With Knee Osteoarthritis

Abstract

Objective: This study investigated the difference in lower limb function between supinated and neutral foot postures in patients with knee osteoarthritis (KOA) scheduled for total knee arthroplasty (TKA).Methods: This study included 62 female patients with KOA knees. Patients were classified into the neutral foot posture group (n = 33 (53%)) and the supinated foot posture group (n = 29 (47%)) using the Foot Posture Index-6 (FPI-6). Femorotibial angle (FTA), knee flexion range of motion (ROM), ankle dorsiflexion ROM, knee extension strength, toe grip strength (TGS), Timed Up and Go (TUG) Test, and knee pain were compared between the two groups.Results: The supinated foot posture group had significantly lower knee flexion ROM, ankle dorsiflexion ROM, knee extension strength, TGS, and larger FTA than those in the neutral foot posture group. However, no significant differences were observed in TUG or knee pain.Conclusion: KOA patients with supinated feet have reduced lower limb strength and ROM, suggesting that incorporating foot alignment assessment into KOA rehabilitation is important. However, long-term studies are needed to clarify causal relationships.