Surgical Normalization of the Shoulder Joint in Obstetric Brachial Plexus Injury

Obstetric brachial plexus injuries (OBPI) result in bony derangements that include posterior humeral head subluxation, glenoid retroversion, and joint incongruity. Often these deformities are accompanied by scapular hypoplasia, elevation, and rotation, which further exacerbate shoulder dysfunction. The purpose of the current study was to investigate the effects of triangle tilt surgery on glenohumeral joint anatomy in 100 OBPI patients. The triangle tilt surgery restores the distal acromioclavicular triangle from an abnormal superiorly angled position to a neutral position, thereby restoring normal glenohumeral anatomic relationships. Axial computed tomography and magnetic resonance images taken before and 12- to 38-months after surgery showed significant improvements in both posterior subluxation and glenoid version. Patients with complete posterior glenohumeral dislocation improved from 19% preoperatively, to 11% postoperatively. Glenoid shape was also improved, with 81% of patients classified as concave or flat after surgery compared with 53% before surgery. Triangle tilt surgery allows for both repositioning and remodeling of the glenohumeral joint. These anatomic improvements after triangle tilt surgery hold promise for improving shoulder function and quality of life for OBPI patients.