Anatomic study of pedicled bipolar teres major transfer for irreparable posterosuperior rotator cuff tears

Background: Treatment of rotator cuff (RC) tears has not included bipolar muscle-tendon transfers to date. The objective of this study was to verify the feasibility of pedicled bipolar teres major (TM) transfer over and under the long head of the triceps brachii (LHT) and compare its versatility with monopolar transfer in a model of supraspinatus (SS) tears in cadavers. Methods: In 6 shoulders of cryopreserved cadavers, we re-created complete SS tears, conducting monopolar and bipolar TM transfers over and under LHT. We compared the morphology of the SS and TM, defect coverage, angle between the transferred TM and major SS axis, and axillary nerve overlap with each technique. Results: The TM and SS were morphologically similar. Defect coverage was significantly lower with monopolar transfer (12 +/- 4 mm) than with bipolar transfer (39 +/- 9 mm under the LHT, P= .003, and 38 +/- 8 mm over the LHT, P = .004). The bipolar transfer course over the LHT was the nearest to the SS axis (39 degrees +/- 11 degrees, P = .005). We found a greater axillary nerve overlap with bipolar transfer under the LHT (27 +/- 8 mm) than with bipolar transfer over the LHT (1 +/- 2 mm, P = .005) or monopolar transfer (0 mm, P < .001). Conclusion: Bipolar TM transfer is possible without neurovascular pedicle interference, obtaining greater RC defect coverage and the closest path to the SS axis when conducted over the LHT compared with monopolar or bipolar transfer under the LHT. Accordingly, it can be considered an alternative option for the treatment of posterosuperior RC defects. (C) 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.