Pectoralis major tendon transfer in reverse total shoulder arthroplasty with irreparable subscapularis: surgical technique and preliminary clinical and radiological results.

HYPOTHESIS/BACKGROUND: Addressing irreparable subscapularis in conjunction with reverse total shoulder arthroplasty (RTSA) presents challenges. RTSA without subscapularis repair leads to similar clinical results compared to those with a subscapularis repair but with less range of motion in internal rotation (IR). Optimization of IR and anterior stability after RTSA, in the setting of an irreparable subscapularis may be achieved with a pectoralis major (PM) tendon transfer. This study aims to describe a novel surgical technique involving PM transfer in RTSA for irreparable subscapularis and report the initial clinical and radiological outcomes.

METHODS

This study included 13 patients with an average of 65.5 years (range, 52-82 years). All patients underwent a lateralized RTSA with concurrent PM transfer, associated to an irreparable subscapularis, performed by a single surgeon (PV). Preoperative and postoperative range of motion, including internal rotation 1, internal rotation 2, external rotation 1 (ER1) and forward elevation, were measured. The absolute Constant score, the age and sex-adjusted Constant Murley score, Visual Analog Scale and subjective shoulder value were evaluated by the same surgeon. Standard X-rays, preoperative magnetic resonance imaging, and computed tomography scan were performed for all patients.

RESULTS

With an average follow-up of 37 months, the mean Constant score improved from 17.7 preoperatively to 61 postoperative ( < .05). Postoperative clinical outcomes significantly improved across the study group. Mean internal rotation 2 increased from 44.6° to 61.5° ( < .05), while internal rotation 1 improved from 2.6 to 5 ( < .05). The Gerber test yielded positive results for all patients, while the belly press test was negative for eleven patients. Postoperative imaging assessment of the transferred PM tendon transfer showed intact repair, a good cicatrization on the lesser tuberosity with excellent trophicity of the muscle without any fatty infiltration in all patients.

CONCLUSION

PM transfer combined with a lateralized RSTA in cases of irreparable subscapularis leads to improved shoulder range of motion, particularly in IR, increased strength and pain relief.