The clinical and biomechanical applications of the lower trapezius tendon transfer: a scoping review of techniques and outcomes.

Background: Lower trapezius (LT) transfers have recently emerged as a surgical option for restoring shoulder function in patients with irreparable rotator cuff tears and previously to restore external rotation in patients with brachial plexus palsy. This technique was developed to address the limitations of traditional tendon transfers, such as latissimus dorsi and pectoralis major transfers, which are often complicated by issues like denervation, postoperative weakness, and altered shoulder biomechanics. Methods: A comprehensive search was conducted across MEDLINE, Scopus, and Web of Science, using keywords related to lower trapezius transfer and its different techniques and outcomes. Following an initial yield of 81 articles and the removal of duplicates, with 31 of them ultimately meeting the eligibility criteria for inclusion. Results: Analysis of the identified studies demonstrates significant improvements in external rotation, forward flexion, and abduction following LT transfers, as well as functional scores. Biomechanical studies showed that LT transfers improve external rotation better in adduction. Technique studies showed that most authors performed the transfer through an open approach and with the use of allografts; however, some authors used arthroscopic-assisted lower trapezius transfer and others use autograft to extend the lower trapezius tendon. Conclusion: LT transfers present a promising surgical option for restoring shoulder function in patients with irreparable rotator cuff tears and those with paralytic sequelae affecting external rotation. Their biomechanical compatibility and potential for improved reinnervation make them a favorable alternative to traditional techniques. This systematic review aims to reinforce the argument for LT transfers as a viable option to restore shoulder kinematics in cases of massive irreparable cuff tears and in cases of obstetric brachial plexus palsy sequele in pediatrics and adults age groups.