Glenoid morphology in obstetrical brachial plexus lesion: a three-dimensional computed tomography study.

BACKGROUND: Obstetric brachial plexus lesion (OBPL) frequently leads to glenohumeral dysplasia, and excessive retroversion of the glenoid is among the best known developmental disturbances. Most analyses of the glenoid are based on 2-dimensional (D) imaging and do not address glenoid inclination or provide information on the glenoid in the sagittal plane. We aim to describe the 3-D deformity of the glenoid in children with OBPL.

METHODS: Preoperative computed tomography (CT) scans of the nonaffected and the affected scapula of 24 children (aged 5 to 12 years) with developmental disturbances after OBPL years were analyzed. The dimensions of the scapula and the deformation of the glenoid were visualized in 3-D.

RESULTS: The retroversion of the glenoid fossa was greater in all affected shoulders, and 2-D measurements significantly overestimated retroversion compared with angles measured in 3-D. The inclination of the glenoid fossa was altered, and a distal bony edge loss was observed on 3-D reformations in the sagittal plane. The reliability of the measured angles was excellent, and the κ agreement for the description of the glenoid form was substantial. Furthermore, the dimensions of the scapula were significantly smaller on the affected shoulders.

CONCLUSION: OBPL is indeed a 3-D disorder. Our measurements revealed excessive retroversion of the glenoid fossa, and the reliability of the 3-D CT measurements was superior to their 2-D counterparts. 3-D CT reformations of the glenoid in the coronal and the sagittal plane added further to 3-D understanding of glenoid morphology in OBPL. These new findings legitimatize a 3-D CT-based description of the glenoid deformities connected with OPBL.