The effects of different elevations of laterally wedged insoles with subtalar strapping on medial compartment osteoarthritis of the knee

Objective: To assess the radiographic and symptomatic effects of treating patients with medial compartment osteoarthritis (OA) of the knee with laterally wedged insoles with subtalar strapping of varying elevations. Design: Prospective quasi-experimental evaluation. Setting: Outpatient clinic in Japan. Participants: Sixty-two women outpatients with knee OA who were randomized into 3 groups according to their birth dates and wedge elevation. Interventions: Participants wore laterally wedged insoles with subtalar strapping with elevations of 8, 12, or 16mm for 2 weeks. Main Outcome Measures: Standing radiographs were used to analyze the femorotibial angle for each subject, both with and without their respective unilateral insoles. The remission scores of the Lequesne index of severity for knee OA were compared among the 3 groups at the conclusion. Participants were asked to report adverse effects on use of the insoles. Results: The 16-mm group (n=21) showed a significantly greater valgus correction of the femorotibial angle than the 8-mm group (n=20) (P=.013). The remission score was significantly improved in the 12-mm group (n=21) compared with the 16-mm group (P=.029). Adverse effects were more common in the 16-mm group (9/21, 42.8%) than in the 12-mm (3/21, 14.3%) or 8-mm (2/20, 10%) groups. Conclusions: The degree of change in femorotibial angle with the insole with subtalar strapping was affected by the tilt of the lateral wedge. For constant routine use, the 8- or 12-mm elevation wedged insoles with subtalar strapping may be more comfortable and effective than the 16-mm elevation wedge.