Gait changes in individuals with bilateral hallux valgus reduce first metatarsophalangeal loading but increase knee abductor moments.

Hallux valgus (HV), one of the most common foot pathologies in modern society, affects not only the foot itself, but also the other lower limb joints. The purpose of the study was to investigate the kinematic and kinetic changes in the lower limb joints in patients with bilateral HV during level walking. Twelve female patients with bilateral HV and 12 healthy female controls walked while three-dimensional kinematic and kinetic data were measured. Patients with HV were found to shift their center of pressure (COP) laterally away from the 1st metatarsophalangeal joint (MPJ), which helped unload the joint during late stance. The lateral shift of the COP in these patients was associated with the reduced toe-out angles of the foot as a result of increased internal rotation of the hip. However, this strategy increased the abductor moments at the knee, an index closely correlated with the medial load at the knee and a predictor of the onset and progression of medial OA. Early treatment of HV may be helpful not only for reducing foot pain and deformity, but also for preventing the potentially harmful loading at the knee, especially in those at risk of medial knee OA.