Comparison of the Effect of Insole Correction on Three-Dimensional Knee Joint Moments during Gait in Standing Workers with Leg Length Discrepancy

Abstract

Background Few studies have been performed to investigate the correction of leg length discrepancy (LLD) on the kinetic characteristics of the knee joint using a shoe insole during gait among those who must stand while working. Purpose To verify three-dimensional (3D) knee joint moments using a 3D motion capture system and force platforms with and without insoles during gait in standing workers with LLD. Study design This was a repeated-measures design. Methods Twenty-seven standing workers with LLD participated in this study. Kinetic data of the knee joint were collected using a motion analysis system and two force platforms. The participants were asked to walk freely along a 6-m walkway wearing a standard pair of shoes or standard shoes with an LLD-corrected insole. Repeated-measures analysis of variance (ANOVA) was used to compare the knee joint moments according to shoe conditions and limb sides. Results There were significant differences in most moment variables related to the knee joint in participants with LLD-corrected insoles worn on the short limb except for the knee moments of adduction, abduction, and internal rotation (<italic>p</italic>&lt;0.05). Significant differences were shown in the maximal moment of knee adduction, abduction, internal rotation, and external rotation between the long and short legs when the participants wore standard shoes only during gait (<italic>p</italic>&lt;0.05). Conclusions The results demonstrated a significant association between the imbalance of the knee moments and LLD among retail staff who must stand while working. Therefore, the results of this study will be useful in explaining the incidence and biomechanical characteristics of knee osteoarthritis in standing workers with LLD.