Objective: To clarify the indications and to describe the surgical technique and outcomes of surgery involving transfer of the trapezius to the deltoid for the treatment of lesions of the brachial plexus in patients with multidirectional instability in the shoulder. Method: In 17 patients (mean age, 23 years) operated at Sao Vicente de Paulo Hospital and the Institute of Orthopedics and Traumatology of Passo Fundo, Brazil from 1999 to 2009, we performed trapezius transfer to the proximal humerus. In these patients, the mean interval between trauma and surgery was 8 months. Results: Functional improvement and resolution of multidirectional instability of the shoulder were observed in all the patients. No patient showed immediate postoperative complications. The mean active mobility was as follows: 95° flexion, 50° abduction, 45° external rotation, and internal rotation at the level of the first lumbar vertebra (L1). The trapezius muscle strength was classified as grade III, and the UCLA functional outcome was 22 points. The postoperative satisfaction was excellent, and occasional pain and weakness was reported by all the patients. Conclusions: Transfer of the trapezius muscle to the proximal humerus provides better results in patients with a more than 6-month-old lesion. This procedure also preserves passive mobility of the limb, confers shoulder stability, provides active mobility, and prevents osteoarthrosis.
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