The contralateral unimpaired arm as a control for upper extremity kinematic analysis in children with brachial plexus birth palsy

Background: Kinematic studies of abnormal upper extremity (UE) motion provide the unique and valuable perspective of motion analysis during simulated functional tasks. However, they require comparison with healthy control data. Obtaining this control data usually entails testing a healthy population, which can be costly and time consuming, requiring separate subject inclusion criteria, recruitment, and institutional review board approval. The kinematics of the unimpaired UE in people with unilateral impairment have not been analyzed and documented. The purpose of this study was to compare UE motion during activities of daily living in the contralateral unimpaired ami. of subjects with brachial plexus birth palsy (BPBP) with an age-matched control population. Methods: The contralateral arms of 40 subjects with unilateral BPBP were compared with the arms of 15 healthy subjects using an established 3-dimensional upper extremity motion analysis protocol. Results: There were no significant differences between the 2 arms on 17 of 19 motion parameters. The 2 differences that were statistically significant (P < 0.05) were not clinically meaningful. Conclusions: The contralateral arms of children with unilateral BPBP can be used as controls for future upper extremity motion analysis studies of this population, and further recruitment of age-matched controls is not necessary for comparison with 5- to 8-year-old children with BPBP. Level of Evidence: This is a retrospective study, investigating whether the contralateral unimpaired arm can be used as a control for upper extremity kinematic analysis in children with BPBP, with a level 2 evidence rating.