Shoulder internal rotation contracture in brachial plexus birth injury: proximal or distal subscapularis release?

ABSTRACT Background In cases of brachial plexus birth injury (BPBI) with internal rotation (IR) contracture of the shoulder, the subscapularis muscle may be released proximally, from the subscapular fossae, or distally, along with peri-articular soft-tissues anterior to the glenohumeral joint. We hypothesized that the indication of each procedure relied primarily on patients’ bone remodeling potential and peri-articular soft-tissue contractures, performing proximal releases in patients younger than 4 years of age and peri-articular distal releases in older patients. The purpose of this study was to analyze the outcomes that such strategy could provide. Methods All patients presenting with BPBI-related shoulder IR contractures who underwent a subscapularis release were included; in addition, in order to restore the joint axial balance, the infraspinatus was systematically reanimated with a tendon transfer (i.e., latissimus dorsi or lower trapezius) in the same operating time. Charts review yielded pre- and postoperative clinical and radiographic measurements, including active and passive ranges of motion of the shoulder in external rotation (ER) with the arm at the side of the body, modified Mallet scores, glenoid versions (GV), and percentages of the humeral head anterior (PHHA) to the middle of the glenoid. Results Between 2012 and 2018, 28 children were operated on at our institution. In patients who underwent proximal subscapularis releases (n = 13), significant improvements were observed regarding active and passive shoulder ER, modified Mallet scores, GV and PHHA, averaging respectively 58 ± 32° (p Conclusion When combined with axial rebalancing of the joint, the proximal release of the subscapularis muscle appears to be sufficient to provide satisfactory functional outcomes in patients with great bone remodeling potential and supple peri-articular soft-tissues. In older patients, a more comprehensive release of the glenohumeral joint anterior aspect seems to provide lower but still significant clinical improvements. Level of Evidence Level IV; Case Series; Treatment Study