Impact of Contralateral Shoe Lifts on Gait Parameters and Mechanics When Wearing a Controlled Ankle Movement (CAM) Boot.

Background: A controlled ankle movement (CAM) walking boot introduces an artificial leg length discrepancy (LLD), which alters gait mechanics and may increase pain. Using a contralateral shoe lift in conjunction with the CAM boot is a common strategy to address this discrepancy; however, the extent to which the shoe lift restores gait biomechanics remains understudied. This study investigates the effects of the combination of CAM boot and contralateral shoe lift on gait parameters compared to normal (shod) conditions. Methods: Thirty healthy adults (mean age 24.6 ± 7.9 years), including 15 men and 15 women, walked overground under 3 conditions: normal shod walking, unilateral CAM boot, and CAM boot with a contralateral shoe lift. A Vicon motion capture system tracked 16 markers to calculate spatiotemporal gait parameters as well as hip and knee kinematics and kinetics using the Plug-in-Gait model. A 1-way analysis of variance followed by Tukey pairwise comparisons identified significant effects of walking condition on various gait characteristics. Results: The CAM boot with shoe lift restored kinematic parameters, including hip flexion (P = .036), knee flexion (P = .023), and hip abduction (P = .038), as well as kinetic parameters including knee axial compression force (P = .014) and hip medial-lateral force (P = .007), to normal walking levels on the booted limb. The reported P values reflect differences observed with the CAM boot alone, which were eliminated by the shoe lift. Conclusion: A corrective contralateral shoe lift used with a CAM boot can restore some of the knee and hip kinematic and kinetic alterations introduced by the CAM boot. However, it has limited effect on other gait parameters and does not fully replicate the mechanics of normal shod walking. Level of Evidence: Level IV, case series.