Optimizing reverse total shoulder arthroplasty for combined loss of elevation and external rotation: latissimus dorsi and teres major transfer, lateralization, or both?

Background: Large to massive rotator cuff tears (RCTs) can lead to combined loss of active elevation and external rotation (CLEER), particularly when accompanied by severe fatty change of the external rotators. In such cases, reverse total shoulder arthroplasty (rTSA) may be insufficient, and adjunctive latissimus dorsi and teres major (LD/TM) transfer or lateralization is often considered, though their relative benefits remain unclear. Methods: This retrospective study included 38 shoulders from 38 patients with combined loss of active elevation and external rotation due to large to massive RCTs and severe fatty change of the infraspinatus and teres minor. All patients underwent rTSA and were followed for a minimum of 2 years. Patients were categorized into 4 groups based on the humeral component design and whether LD/TM transfer was performed: inlay component without muscle transfer (In group), onlay component without muscle transfer (On group), inlay component with muscle transfer (InT group), and onlay component with muscle transfer (OnT group). Lateralization was assessed radiographically by measuring the distance from the glenoid to the humeral component center and the greater tuberosity. Post-operative outcomes were evaluated in terms of active range of motion, the American Shoulder and Elbow Surgeons (ASES) score, and the Constant-Murley score. Radiographic and clinical results were compared across groups. Each outcome was evaluated relative to its minimum clinically important difference (MCID). Results: The In, On, InT, and OnT groups included 9, 7, 10, and 12 patients, respectively, with a mean follow-up of 38 months (range, 24-61). All groups showed significant improvements in forward elevation, ASES scores, and Constant-Murley scores at 24 months ( Conclusion: LD/TM transfer was associated with restoring external rotation, whereas humeral lateralization seemed related to better post-operative internal rotation. Among the treatment strategies evaluated, rTSA incorporating both LD/TM transfer and humeral lateralization was associated with better outcomes in this challenging patient population.