Can orthotic insoles prevent lower limb overuse injuries? A randomized-controlled trial of 228 subjects.

Lower limb overuse injuries are common among people who are exposed to physical stress. Orthotic shoe insoles are widely used to prevent lower limb overuse injuries. Here, we conducted a randomized-controlled study to examine whether the use of orthotic insoles prevents lower limb overuse injuries. Participants (n=228) were randomly assigned to use (n=73) or not to use (n=147) orthotic insoles. The insoles were molded to the shape of the foot to provide support during physical activity. The main outcome measure in the present study was the physician-diagnosed lower limb overuse injury. Thirty-four (46.6%) subjects in the insole group were diagnosed with a lower limb overuse injury compared with 56 (38.1%) in the control group (P=0.29) during the 6-month study period. When body mass index and the results of a 12-min running test and muscle strength were adjusted in a Cox's regression model, the hazard ratio for lower limb overuse injury in the insole group was 1.3 (95% confidence intervals: 0.8-2.1) compared with the control group. Use of orthotic insoles was not associated with a decrease in lower limb overuse injuries. Our findings suggest that routine use of orthotic insoles does not prevent physical-stress-related lower limb injuries in healthy young male adults.