CORR Insights®: What Range of Motion is Achieved Five Years After an External Rotationplasty of the Shoulder in Infants with Obstetric Brachial Plexus Injury?

Abstract

There is abundant work on brachial plexus birth palsies and I want to highlight current literature on the indications and results of soft-tissue releases and tendon transfers. While the subscapularis is the most commonly released tendon in this setting, other soft-tissue structures that can be released include the anterior capsule, the coracohumeral ligament, and the pectoralis major (usually as a z-plasty); resection of the coracoid sometimes is done to achieve improvement of global abduction and external rotation of the shoulder. A meta-analysis published in 2013 showed open release of the subscapularis was superior to arthroscopic release to improve global abduction of the shoulder, but improvement of external rotation between the two groups was the same [5]. In contrast, another study found that arthroscopic release of the subscapularis was superior to open z-plasty of the pectoralis major when measuring abduction, Mallet scores, active external rotation and hand-to-head motion. All the children in this study also had latissimus dorsi and teres major tendon transfers done at the same time as the soft-tissue release. It is important to note that this study demonstrated improvement in all children, but recommended consideration of arthroscopic soft-tissue release since it is less invasive [9]. Finally, two studies found remodeling of the glenohumeral joint if the mechanics of the shoulder are restored early. They used MRI or CT to demonstrate a more-central position of the humeral head on the glenoid and improvement of the glenoid retroversion [1, 4]. Surgeons need to know that remodeling is possible if these procedures are done early enough and not to delay treatment. Two studies looking specifically at the child’s age at the time of procedure and remodeling potential found that performing soft-tissue releases and tendon transfers on children up to 5 years of age will produce sufficient remodeling over time [3, 4], which tends to decrease the likelihood that humeral osteotomy will be indicated. There is at least agreement that the most helpful tendon transfers include the latissimus dorsi and the teres major [1, 6, 7, 9, 11]. This helps researchers in the field focus on the questions that we do not have answered yet. In the current study, Sarac and colleagues [10] found that young children with obstetric brachial plexus palsies can benefit from soft-tissue release and when there is a lack of active external rotation, a tendon transfer should be added. While these results echo the findings in earlier studies [1, 4, 6, 8], the current study is unique because it had a large number of children and 5-year follow-up. Indeed, the majority of the literature on this topic are small case series or small retrospective reviews.