Editorial Commentary: Biomechanical Data and Early Clinical Results Demonstrate an Emerging Strategy for Combining Superior Capsule Reconstruction and Lower Trapezius Transfer in the Management of Massive Irreparable Posterosuperior Rotator Cuff Tear

Abstract

Numerous biomechanical studies demonstrate that superior capsule reconstruction (SCR) improves glenohumeral superior translation and subacromial contact pressures in cadaveric models of massive irreparable rotator cuff tears (MIRCT) at time zero. These findings provide a logical basis for clinical observations of significant improvements in pain, range of motion, and patient-reported outcome measures at short-term follow-up. However, the efficacy of SCR at longer-term follow up is controversial, and a recent survey of AANA members demonstrates that there is decreasing use of SCR for MIRCTs as the result of concerns regarding poor clinical results, high failure rates, and high rates of progression of arthritis. To improve the outcomes of SCR, some authors have suggested a strategy of combining an SCR with a lower trapezius transfer (LTT). Biomechanical studies report improved restoration of shoulder kinematics and contact pressures compared with SCR or LTT alone. One of the risk factors for failure of SCR is infraspinatus atrophy. Because LTT has similar direction and excursion to the infraspinatus, LTT can abolish external rotation lag and improve external rotation strength; adding LTT to SCR might help restore the force couple. In addition, LTT provides a dynamic stabilizer effect whereas SCR predominantly provides a static stabilizer effect. In high abduction angles (greater than graft fixation angles) the SCR graft can no longer act to prevent humeral head migration because it is lax. Addition of a dynamic stabilizer could improve shoulder biomechanics. However, clinical efficacy is not well defined, and concerns exist regarding the considerable additional cost of the procedure in terms of operative time and the use of additional grafts and implants. Furthermore, the role of the procedure in the management of MIRCTs is unclear because comparative studies against other procedures such as debridement alone, partial repair, independent SCR or tendon transfer, subacromial balloon spacer, biologic tuberoplasty, acromial resurfacing, and reverse shoulder arthroplasty are lacking.