Poster 146: The effect of varying elevation of laterally wedged insoles on valgus correction of the femorotibial angle and symptomatic improvement in medial compartment knee osteoarthritis.

Abstract

Objective: To assess the dose effect of varying the elevation of laterally wedged insoles with subtalar strapping on radiographic alignment and symptoms in patients with osteoarthritis (OA) of the knee with varus deformity. Design: Randomized prospective study. Setting: Outpatient clinic. Intervention: 62 new female outpatients with knee OA were treated for 2 weeks with a lateral wedge with elevations of 8, 12, or 16mm with subtalar strapping. Main Outcome Measures: Femorotibial angles on standing radiographs were analyzed for each subject, with and without their respective unilateral insole. The remission scores of Lequesne index of severity for knee OA were compared among the 3 groups. Participants were asked to report the adverse effects of using the respective insoles. Results: The 16-mm group (n=21) demonstrated a significantly greater valgus correction of the femorotibial angle than the 8-mm group (n=20) ( P=.013). There was no significant difference in the correction angle between the 16- and 12-mm groups (n=21) ( P=.32). The remission score was significantly greater in the 12-mm group than in 16-mm group ( P=.029). Reports of adverse effects were greater in the 16-mm group (9/21, 42.8%) than in 12-mm (3/21, 14.3%) or the 8-mm (2/20, 10%) groups. Conclusions: Height of the lateral wedge in an insole with subtalar strapping effects the femorotibial angle. The subtalar strapping insole with an elevation of 12mm may be more comfortable than that of either 8- or 16-mm wedges for constant normal use.