Conjoint tendon release results in improved internal rotation and pain following reverse shoulder arthroplasty: a combined randomized clinical trial and biomechanical study.

Abstract

Reverse shoulder arthroplasty (rTSA) reliably restores active forward elevation of the shoulder, but internal rotation is often unsatisfactorily restored or even lost after rTSA. This limited internal rotation is one of the independent factors that negatively affect patients' subjective rating of the procedure. The purpose of this study was to investigate the effect of conjoint tendon release during rTSA on various clinical and biomechanical parameters including internal rotation through a randomized clinical trial as well as a cadaveric study. Randomized clinical trial: patients undergoing primary rTSA for osteoarthritis, cuff tear arthropathy, or massive rotator cuff tear were prospectively enrolled and randomized into 2 groups (release vs. control group). The release group received a complete release of the conjoint tendon. Range of motion including active internal rotation, pain visual analog scale scores, patient-reported outcome measures, and complication profiles were compared between the 2 groups at 12 months. Cadaveric study: rTSA was performed through the deltopectoral approach in 6 shoulder specimens. The tension of the conjoint tendon, shoulder extension, internal rotation angle, and force required to subluxate the joint were measured before and after conjoint tendon release in each specimen and compared. Randomized clinical trial: a total of 55 patients were enrolled for the clinical trial with 27 in the release group and 28 in the control group. The mean internal rotation level was significantly higher (P = .001, mean difference [MD] = 1.2, 95% confidence interval [CI] = 0.2, 1.8), and the mean pain visual analog scale score was significantly lower (P = .002, MD = 1.0, 95% CI = 0.3, 1.7) in the release group than in the control group. There were no significant differences in patient-reported outcome measures and complication profiles between the groups. Multiple regression analysis showed that performing conjoint tendon release and preoperative internal rotation were the only independent predictors of the postoperative internal rotation following rTSA. Cadaveric study: conjoint tendon release resulted in significantly greater internal rotation (P = .003, MD = 8°, CI = 4°, 12°) and greater extension of the shoulder (P < .001, MD = 7°, CI = 4°, 9°), significantly lower conjoint tension (P < .001, MD = 4.7 N, CI = 3.2 N, 6.2 N), and significantly lower force required to subluxate (P = .015, MD = 4.3 N, CI = 1.0 N, 7.7 N) compared to the status before tendon release. This study suggests that conjoint tendon release can be a safe and effective option for addressing internal rotation limitations following rTSA, although further research is needed to clarify the exact indications for this procedure.