Long-term Effect of Using Inner And Outer Medical Insoles on Dynamics of Lower Limb Joints in Men With Mild Leg Length Discrepancy During the Stance Phase of Gait: A Randomized Clinical Trial

The use of medical insoles is one of the non-surgical treatment methods for improving the gait pattern of individuals with leg length discrepancy (LLD). However, the long-term effect of insoles on lower limb joint dynamics in these individuals is still unclear. This study aims to investigate and compare the long-term effect of inner and outer insoles on selected dynamics variables of the lower limb joints in men with LLD during the stance phase of gait.

This is a randomized clinical trial with a pre-test/post-test design on 18 men with mild LLD, randomly divided into two parallel groups of inner insole and outer insole. Selected dynamics parameters were measured by six cameras and a force plate during the stance phase of gait. Both groups used the insole for 12 weeks for at least four hours per day. Repeated-measures ANCOVA was used to test the hypothesis. P≤0.05 was statistically significant.

After 12 weeks of using insoles, the peak lateral pelvic tilt decreased significantly in the inner insole group (P=0.041 for short leg, and P=0.008 for long leg) and outer insole group (P=0.026 for short leg, P=0.007 for long leg). The peak knee abduction moment (P=0.022 for inner insole, P=0.007 for outer insole) and peak hip abduction moment (P=0.006 for inner insole, P=0.005 for outer insole) also decreased significantly. In the outer insole group, the peak anterior pelvic tilt showed a significant change in the post-test stage compared to the pre-test stage (P=0.014 for short leg, and P=0.033 for long leg). There was no significant difference between the two groups in the selected dynamics variables (P>0.05).

The long-term use of inner and outer medical insoles, by causing a change in the lower limb joint dynamics, can lead to a positive adaptation in men with mild LLD. There is no significant difference in the long-term effect of inner and outer insoles.