109 patients with mild to moderate osteoarthritis of the medial compartment of the knee were included in this study to determine the effect lateral wedge insoles have on hip and ankle joint space width. Patients were randomized to a lateral wedge orthosis or a neutral wedge orthosis for use over a 36-month period. Only 45 patients were available at final follow-up (31 Lateral wedge, 14 neutral wedge). Both groups demonstrated significant reductions in joint space width at the index hip and contralateral hip compared to baseline, however, there were no differences between groups. There were no differences in ankle joint space width within either group or between groups. While this study indicates that lateral wedge insoles do not appear to have a negative effect on hip and ankle joint space width over a 36-month period, the results should be interpreted with caution due to the substantial loss to follow-up.