Background: Characterization of glenohumeral deformities secondary to brachial plexus birth palsy with plain radiography is difficult because the glenohumeral joint does not completely ossify until puberty. The purpose of this study was to compare the findings on magnetic resonance imaging and arthrography with those on arthroscopy to better understand the roles of these methods in the evaluation of glenohumeral development in this condition.
Methods: Eighty-four children who ranged in age from seven months to thirteen years and six months had glenohumeral arthrography while they were under general anesthesia for operative treatment of an internal rotation contracture. Thirty-six children also received magnetic resonance imaging with use of cartilage-sensitive axial gradient-echo sequences. Thirty-seven children were evaluated arthroscopically.
Results: Arthrography showed a concentric glenohumeral joint in thirty-three children, a flat glenoid in eight, a biconcave glenoid in seventeen, and a pseudoglenoid in twenty-six. Thus, 61% (fifty-one) of the eighty-four children with an internal rotation contracture had a substantial deformity. The severity of the contracture was associated with the existence and the type of the deformity (p = 0.001). Magnetic resonance imaging showed greater detail than arthrography did in defining the severity of the deformity in both the glenoid and the humeral head. The thirty-seven children who were examined arthroscopically showed a progression from those who had a concentric, conforming joint to those who had a markedly deformed joint with a bifurcated glenoid and a flattened, oval-shaped humeral head that articulated with the posterior aspect of the glenoid. Irregularities and cavitation of the anterior aspect of the glenoid were common. The subscapularis and rotator interval tissue were the primary sites of contracture.
Conclusions: Profound glenohumeral deformities secondary to brachial plexus birth palsy are commonly seen within the first two years of life. The information provided by imaging studies is helpful in defining the natural history of this condition and in determining the success of surgical intervention.
Level of Evidence: Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients [with universally applied reference "gold" standard]). See Instructions to Authors for a complete description of levels of evidence.