Effects of orthotic insoles on gait kinematics and lowback pain in patients with mild leg length discrepancy

Abstract

Background: Mild leg length discrepancy increases biomechanical asymmetry during gait, which leads to low-back pain. Orthotic insoles with a directly integrated heel lift were used to reduce this asymmetry and thus the associated low-back pain. The aim of this study was to analyze the biomechanical adaptations of the locomotor apparatus during gait and the subjective pain ratings before and after the establishment of orthotic insole use. Methods: Eight patients with mild leg length discrepancy (≤2.0 cm) underwent threedimensional biomechanical analysis while walking before and after 3 weeks of orthotic insole use. Low-back pain was assessed separately before both measurement sessions using a visual analog scale. Results: Analysis of the kinematic parameters highlighted individual adaptations. The symmetry index of Dingwell indicated that orthotic insoles had no significant effect on the kinematic gait parameters and an unpredictable effect across patients. Orthotic insole use significantly and systematically (in all of the patients) reduced low-back pain (P, .05), which was correlated with changes in ankle kinematics (P ¼ .02, r ¼ 0.80). Conclusions: The effects of orthotic insoles on gait symmetry are unpredictable and specific to each patient’s individual manner of biomechanical compensation. The reduction in low-back pain seems to be associated with the improved ankle kinematics during gait. (J Am Podiatr Med Assoc 111(4): 1-10, 2021).