Comparative Efficacy of Latissimus Dorsi and Teres Major Versus Pectoralis Major Tendon Transfers Combined with Exactech Equinoxe Reverse Total Shoulder Arthroplasty in Improving Internal Rotation: A Preliminary Result.

Abstract

Background: Reverse total shoulder arthroplasty (RTSA) is effective in treating massive irreparable rotator cuff tears (mRCT) and cuff tear arthropathy (CTA); however, improving internal rotation (IR) remains challenging. Tendon transfers have been introduced to improve active IR alongside RTSA, yet no clinical studies have compared their effectiveness. This study compares the clinical efficacy of RTSA combined with latissimus dorsi and teres major (LDTM) and pectoralis major (PM) transfers in improving IR in patients with mRCT and CTA who have a loss of active IR.

Methods: This retrospective study included 60 patients with mRCT or CTA who experienced a loss of active IR. 37 patients underwent RTSA with LDTM transfer, and 23 underwent RTSA with PM transfer. Clinical evaluations included the American Shoulder and Elbow Surgeons, Activities of Daily Living requiring active Internal Rotation scores, and measurements of active range of motion (aROM), subscapularis-specific examination, and the ability to perform the toileting activities. IR strength was assessed using a dynamometer. Radiologic assessments involved preoperative magnetic resonance imaging, as well as postoperative radiographs and ultrasonography.

Results: Both groups showed significant improvements in all clinical scores and aROM postoperatively (p < .001). No differences were found between the groups in overall clinical scores or forward flexion and external rotation aROM. However, the LDTM group demonstrated significantly greater IR aROM with the arm behind the back (6.4 ± 2.0 vs. 4.6 ± 1.3, p < .001) and better performance in toileting activities (p < .001). By contrast, the PM group had significantly higher IR strength (28.8 ± 3.6 N vs. 24.7 ± 4.0 N, p < .001). The minimal clinically important difference analysis indicated that LDTM more frequently met the IR aROM threshold, whereas PM more frequently reached the IR strength threshold (p = .010, .019, respectively). One case of transient axillary nerve palsy and one acromial fracture was noted in LDTM group, all managed conservatively. Additionally, a traumatic dislocation was observed in the PM group.

Conclusion: Both LDTM and PM transfers combined with RTSA significantly improve clinical outcomes in patients with mRCT and CTA who had a loss of active IR. The LDTM transfer is superior in IR aROM with the arm behind the back, while the PM transfer more effectively improves IR strength in front of body. Preoperative counseling could consider the patient's specific functional needs to guide the selection of the appropriate tendon transfer.