Single Versus Double Tendon Transfer to Improve Shoulder External Rotation During the Treatment of Brachial Plexus Birth Palsy

Abstract

Background: Tendon transfers are commonly performed in patients with brachial plexus birth palsy (BPBP) to improve function. Transferring 2 tendons in patients with C5-7 injury has the potential complication of loss of midline function. The purpose of this study was to investigate whether a single tendon transfer (1TT) as opposed to the traditional double tendon transfer (2TT) resulted in any differences in functional outcomes in patients with C5-7 BPBP. Methods: A retrospective review of all patients with C5-7 BPBP who underwent tendon transfers to improve shoulder external rotation over a 5-year period was performed at 2 institutions. Outcomes were assessed using the modified Mallet (MM) classification scores. Results: Twenty-two C5-7 patients had complete records of preoperative and postoperative MM scores, including 11 sex-matched patients in both the 1TT and 2TT groups. When comparing preoperative and postoperative MM categories, there were significant improvements in both the 1TT and 2TT groups for global abduction (P < .05 and P < .01, respectively) and external rotation (P < .00001 for both). Modified Mallet (MM) hand to neck scores were significantly improved in the 2TT group (P < .05) but not in the 1TT group (P = .053). Internal rotation scores significantly decreased in both groups (P < .001). Both groups demonstrated significant increases in total scores from the preoperative MM scores (P < .01). Conclusion: The 1TT and 2TT procedures result in substantial gains in upper extremity functions for patients with C5-7 BPBP as measured by the MM score, specifically within the global abduction and external rotation subcategories. However, a significant loss occurs in internal rotation for both groups.