Most brachial plexus birth palsies are unilateral injuries. Different methods exist to assess and evaluate limb motion. However, no one technique is universally accepted. Three dimensional upper extremity motion analyses offer an objective evaluation to measure the difference between the uninvolved and involved arms. For children with unilateral brachial birth palsy, if the upper extremity parameters of the contralateral limb do not differ from those of healthy controls, this limb could serve as its own age matched control. The purpose of this study was to determine whether or whether not this hypothesis is true.
Kinematic studies were performed on both arms in forty patients with unilateral brachial plexus birth palsy and fifteen healthy control subjects. A motion analysis system was used to record kinematic data. Each subject was asked to perform five movements intended to simulate specific activities of daily living. Six joint movements about the shoulder, elbow, forearm, and trunk were assessed. The data was statistically analyzed according to the standard protocol. The data is presented in detail and in tabular form within the article. For seventeen of nineteen joint positions, there was no statistical difference between the two groups. There were some minor significant differences during specific motions, however, the clinical significance was unclear.
This data indicates that the contralateral arm of children with unilateral brachial plexus birth palsy can be used as a control. The authors acknowledge that a larger sample size would provide a greater power in standardizing the degree variation and would strengthen their conclusions.
Birth, Palsy, Brachial, Plexus, Motion, Kinematic