Modified Lower Trapezius Tendon Transfer Using an Achilles Tendon-Bone Allograft With Acellular Dermal Matrix Augmentation for Irreparable Posterior-Superior Rotator Cuff Tears.

Lower trapezius (LT) transfer has shown promising clinical outcomes in the treatment of posterior-superior rotator cuff tears. Numerous surgical modifications of LT transfer have been developed, including variations in interpositional graft choices, fixation methods, and graft anastomosis techniques. The most widely adopted method involves the use of an Achilles tendon allograft to bridge the gap between the humerus and the LT. Unlike conventional tendon-only grafts, the technique described in this article retains the calcaneal bone block to facilitate bone-to-bone healing at the humeral footprint. The bony portion is shaped to approximately 5 mm in thickness for optimal fit and is secured using a triple-row suture anchor configuration. To enhance the subacromial spacer effect and reduce friction on the bursal side, an acellular dermal matrix patch is applied over the graft. This technical note outlines a step-by-step approach to arthroscopically assisted LT transfer using an Achilles tendon-bone allograft augmented with an acellular dermal matrix patch for the treatment of irreparable posterior-superior rotator cuff tears.