American Association for Hand Surgery

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One- Versus Two-Tendon Transfer to Improve Shoulder External Rotation During the Treatment of Brachial Plexus Birth Palsy
Joshua M Abzug, MD1, Ellie Miller, MD1, Alexandria L Case, BSE1, Danielle A Hogarth, BS1, Dan A Zlotolow, MD2 and Scott H Kozin, MD2, (1)University of Maryland School of Medicine, Baltimore, MD, (2)Shriners Hospital for Children Philadelphia, Philadelphia, PA


Brachial plexus birth palsy (BPBP) can result in lifelong impairment to the patient. Secondary surgeries, including tendon transfers, are commonly performed to improve shoulder function. However, transferring two tendons, especially in patients with C5-7 injuries, has the potential complication of loss of midline function. The purpose of this study was to investigate if a single tendon transfer (1TT) as opposed to the traditional two tendon transfer (2TT) resulted in any differences in functional outcomes in patients with C5-7 BPBP.


A retrospective review of all BPBP patients that underwent tendon transfers to improve shoulder external rotation over a five-year period was performed at two institutions. All patients with C5-7 BPBP who had tendon transfer surgery were included. Outcomes were assessed utilizing the Modified Mallet Classification (MMC) scores and range of motion measurements.


Twenty-two patients with C5-7 injuries underwent tendon transfers to improve shoulder external rotation over a five-year period at two institutions, with 11 sex-matched patients in each of the single tendon (1TT) and double tendon (2TT) transfer groups. The average age at the time of surgery was 3.6 years (range: 1.0 -5.4 years) in the 1TT and 4.1 years (range: 2.1-12.7 years) in the 2TT group. Both 1TT and 2TT groups demonstrated similar average pre-operative total MMC scores of 14.6 and 15.1, respectively. The average MMC internal rotation score was 3.55 for the 1TT group and 3.82 for 2TT group pre-operatively (p=0.19), and 2.73 and 2.64, respectively, post-operatively (p=0.27). When comparing individual components of the MMC pre- and post-operatively, significant improvements were observed in both the 1TT and 2TT groups for global abduction (p<0.05 and p<0.01, respectively) and external rotation (p<0.01 for both). The MMC hand-to-neck scores were significantly improved in the 2TT group (p<0.05) but not in the 1TT group (p=0.053). Internal rotation scores significantly decreased in both groups (p<0.001). Average total MMC scores at final follow-up appointments for 1TT and 2TT groups were 17.1 and 16.9, respectively (p=0.83). Both groups demonstrated significant aggregate increases in scores compared to the pre-operative MMC scores (p<0.01).


1TT and 2TT procedures result in substantial gains in upper extremity function for patients with C5-7 BPBP as measured by the MMC, specifically within the global abduction and external rotation subcategories. Loss of midline function is a potential complication regardless of transferring one or two tendons when trying to improve external rotation outcomes in BPBP patients with C5-C7 nerve root injuries.

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