Lower limb biomechanics during gait in children with Achondroplasia

Achondroplasia is an autosomal dominant disorder that has been reported to be the most common condition associated with severe disproportionate short stature. A limited number of studies exist in the literature reporting kinematic abnormalities in children with Achondroplasia. Reported deviations include increased pelvic tilt, flexed knees during stance and excessive hip abduction. However, studies lack full 3-dimensional data and results are variable. The aim of this study was to examine differences in 3-dimensional kinematics during gait between children with Achondroplasia and age-matched controls A retrospective analysis was conducted of our gait laboratory database over a 20-year period. Eight children with Achondroplasia and 32 children with typical development were included. A full 3-dimensional kinematic analysis was performed using a CODA mpx30/cx1 active marker system. Increased flexion at all joints in the sagittal plane, increased hip abduction and foot supination in the coronal plane and increased external hip rotation were present for children with Achondroplasia. In contrast to other studies, increased knee varus was not an issue for the children in this study. This study provides a full description of the kinematic patterns associated with children with Achondroplasia and, as such, a comprehensive baseline for planning rehabilitation strategies in these children.