Study design: Randomized controlled trial.
Objectives: To determine if the use of custom shoe orthoses can lessen the incidence of weight bearing-induced back pain.
Summary of background data: The scientific basis for the use of orthoses to prevent back pain is based principally on studies that show that shoe orthoses can attenuate the shock wave generated at heel strike. The repetitive impulsive loading that occurs because of this shock wave can cause wear of the mechanical structures of the back. Previous randomized studies showed mixed results in preventing back pain, were not blinded, and used orthoses for only short periods of time.
Methods: A total of 404 eligible new infantry recruits without a history of prior back pain were randomly assigned to received either custom soft, semirigid biomechanical, or simple shoe inserts without supportive or shock absorbing qualities. Recruits were reviewed biweekly by an orthopaedist for back signs and symptoms during the course of 14 weeks of basic training
Results: The overall incidence of back pain was 14%. By intention-to treat and per-protocol analyses, there was no statistically significant difference between the incidence of either subjective or objective back pain among the 3 treatment groups. Significantly more recruits who received soft custom orthoses finished training in their assigned orthoses (67.5%) than those who received semirigid biomechanical orthoses (45.5%) or simple shoe inserts (48.6%), P = 0.001.
Conclusions: The results of this study do not support the use of orthoses, either custom soft or semirigid biomechanical, as prophylactic treatment for weight bearing-induced back pain. Custom soft orthoses had a higher utilization rate than the semirigid biomechanical or simple shoe inserts. The pretraining physical fitness and sports participation of recruits were not related to the incidence of weight bearing-induced back pain.