Subscapularis Z-lengthening in children with brachial plexus birth palsy loses efficiency at mid-term follow-up: a retrospective cohort study

The aim of this study was to evaluate early and mid-term clinical outcomes after isolated subscapularis Z-lengthening in children with shoulder internal rotation contractures resulting from brachial plexus birth palsy.Children with brachial plexus birth palsy treated with subscapularis tendon Z-lengthening from 2001 to 2011 were retrospectively reviewed. Over this period, 31 patients were identified. Primary outcome was improvement in Mallet score after surgery, and secondary outcome measures were active range of motion and Mallet sub-scores. Clinical outcomes were collected at three time intervals: pre-operatively, one-year post-operative and at latest follow-up.After exclusion, 21 patients remained for further analysis. Mean age at surgery was 3.7 years (range, 1.2-8.7), and mean follow-up length was 6.5 years (2.9-9.7). Moderate improvements were found for mean Mallet score, active external rotation, active abduction and hand-to-mouth movement at one year and latest follow-up. However, improvements in active external rotation and Mallet score were not fully maintained at final follow up.Isolated subscapularis Z-lengthening is effective at early follow-up, but results are not maintained at mid-term follow-up.