How can biomechanical foot orthosis affect gait in arthritis with hallux valgus?

Introduction/Background Hallux valgus (HV) deformity is the most commonly observed forefoot deformity in elderly women patients with arthritis. We investigated the effects of customized biomechanical foot orthosis (BFO) on kinematic data during gait in arthritis with HV deformities compared with normal control group. Material and method Ten arthritis patients with HV deformities and 10 normal women were enrolled in this study. All patients were diagnosed with foot deformities by biomechanical and radiologic studies, and they received the customized BFOs manufactured at a commercial orthosis laboratory (Biomechanics, Goyang, South Korea) according to the strictly defined procedure by a single experienced technician. The kinematic data by the Vicon 3D motion capture system (Oxford Metrics, Oxford, England) were compared in with and without application of the BFO. Results Patients with application of the BFO showed increased gait cadence, walking speed and decreased stride, step time in temporal parameters. Total mean range of motion (ROM) of hallux respect to forefoot was 52.67 degree [dorsiflexion (DF) 34.41; plantar-flexion (PF) 18.26] without BFO, and was increased to 73.12 degree (DF 24.75; PF 48.37) after application of the BFO. During specific gait events, a different range of motion was found at several inter-segment angles. Particularly, the range of motion of the hallux (sagittal plane) and hindfoot (frontal-transverse planes) during stance were significantly different. The averaged position of forefoot during whole gait cycle was persistently abducted in with application of the BFO. Conclusion The application of BFO will be considered to be useful effects for improvement of gait pattern in arthritis with HV deformities by increased ROM of hallux and change of foot position. Our results suggest that it is very important to find out pathophysiology of HV and the effectiveness of BFO on gait pattern in arthritis with HV.