Long-Term Shoulder Outcomes Following Tendon Transfers for Brachial Plexus Birth Injuries

BACKGROUND: Although the majority of children with brachial plexus birth injuries recover spontaneously, permanent functional deficits at the shoulder can be seen following both incomplete spontaneous recovery and microsurgical reconstruction. Incomplete recovery of upper trunk injuries typically results in shoulder internal rotation contractions and muscular imbalances. Tendon transfers are a well-established procedure for improving shoulder function in this population. Long-term outcomes of this procedure remain understudied. METHODS: A retrospective review of patients 5 years of age or younger who underwent tendon transfers for brachial plexus birth injury at a single, tertiary-referral center from the year 2000 to 2022 was conducted. Demographics, clinical and surgical variables, and postoperative outcomes were examined. Paired t tests and Wilcoxon signed-rank tests were utilized to compare preoperative and postoperative scores. RESULTS: Eighty-eight children (61% female, 75% Caucasian) diagnosed with either C5-C6 (71.6%), C5-C7 (13.6%), or total palsy (14.8%) due to a brachial plexus birth injury were identified. Average age at surgery was 28.5±14.6 months, and average follow-up was 8.7±5.0 years. Nerve grafting, nerve transfers, or neurolysis was performed before tendon transfer in 20 patients. Twenty patients underwent isolated latissimus dorsi transfer, while 62 underwent combined latissimus dorsi and teres major transfers. Mean modified Mallet scores improved by +0.60 for abduction, +0.85 for external rotation, and +1.10 for hand-to-mouth (P<0.001). Active external rotation improved by 19.7 degrees, external rotation at 90 degrees improved by 11.0 degrees, and forward flexion improved by 47.2 degrees (P<0.001). Two patients (2.4%) underwent revision tendon transfers, and 16 patients (19.5%) underwent subsequent shoulder procedures. Separately, 6 patients underwent isolated trapezius transfer with no significant changes in preoperative versus postoperative outcomes. CONCLUSIONS: Tendon transfer for brachial plexus birth injury results in long-lasting improvements in shoulder function in young children. Although postoperative complications and subsequent procedures were observed, revisions were infrequent. LEVEL OF EVIDENCE: Level III-retrospective study.