Leg length discrepancy - an experimental study of compensatory changes in three dimensions using gait analysis

Patients with leg length discrepancy (LLD) develop compensatory mechanisms, which result in kinematic alterations in the lower limbs and pelvis. We in vestigated these compensatory mechanisms. Seven normal subjects underwent t hree-dimensional (3-D) gait analysis using a CODA MPX 30(R) analyser. The s ubjects were fitted with raises of varying heights to one lower limb and th en analysed in static and dynamic modes. Pelvic obliquity was the most comm on mechanism used to compensate for small degrees of leg length discrepancy up to 2.2 cm, particularly in static standing. With larger degrees of disc repancy, the subjects developed flexion of the knee of the longer leg. Comp ensatory mechanisms during walking were more complex and included a combina tion of kinematic changes at the pelvis, knee and ankle. We developed mathe matical models for the compensatory mechanisms at all the three levels. We conclude that 3-D gait analysis is a useful tool in the assessment of patie nts with functional and structural leg length discrepancies. (C) 2000 Elsev ier Science B.V. All rights reserved.