Ossification of the proximal humerus in children with residual brachial plexus birth palsy: a magnetic resonance imaging study.

BACKGROUND: Children with residual brachial plexus birth palsy may develop deformities of the humeral head and the glenoid. Surgical treatment has been described to maximize function and to lessen deformity by means of glenohumeral remodeling. The timing and technique of surgical intervention have not been resolved. The timing of the appearance on magnetic resonance imaging of the ossific nuclei in patients with brachial plexus birth palsy has not been described. We examined the timing of ossification about the proximal humerus. Our hypothesis was that the timing of ossification of the proximal humerus differs between the side involved in brachial plexus palsy and the uninvolved side.
METHODS: A retrospective study was performed of 117 children with residual brachial plexus birth palsy (aged 5 mo to 10 y) who had magnetic resonance imaging scans of the bilateral shoulders performed at our institution between 2000 and 2007. All axial slices were reviewed by a single observer for evidence of ossification of the humeral head epiphysis, the greater tuberosity, and the lesser tuberosity, as well as for evidence that the 3 were coalesced. Statistical analysis was performed to compare the involved and uninvolved sides.
RESULTS: The appearance of the greater tuberosity ossific nucleus on the involved side was significantly delayed. There was a trend towards delay in the appearance of the lesser tuberosity ossific nucleus and the coalescence of the 3 ossific nuclei on the involved side. The duration during which ossification of the involved brachial plexus side occurred was generally shorter compared with the uninvolved side.
CONCLUSION: There is delay in the ossification of the involved side in brachial plexus birth palsy, and a shorter duration of ossification.