Subscapularis function after transosseous repair in shoulder arthroplasty: transosseous subscapularis repair in shoulder arthroplasty.

Abstract

Postoperative subscapularis function has been identified as an essential factor influencing the outcome of shoulder arthroplasty. The goal of this study was an evaluation of subjective and objective subscapularis function after transosseous refixation. Twenty-three patients with an average age of 71 years (range, 51-86) and follow-up of 43 months (range, 24-67) were included in this study. The subscapularis was tenotomized from the lesser tuberosity and refixation was performed in a transosseous technique through bone tunnels with nonabsorbable sutures. Subscapularis function was evaluated subjectively by the ability to tuck a shirt and objectively with the lift-off test and strength measurement in internal rotation. Radiological assessment included ultrasound evaluation of the subscapularis and an axillary x-ray. No complete, but 7 partial subscapularis tears were found on ultrasound (30.4%). Five patients were not able to tuck their shirt postoperatively (22.7%). This was associated with an inferior clinical outcome (American Shoulder and Elbow Surgeons [ASES] score 53.3 vs 76.4; P = .023). The lift-off test was positive in 4 patients  (17.4%), which was also associated with an inferior clinical result (Constant score 52.3% vs 74.2%; P = .021). Nineteen patients were able to go through an internal rotation strength testing in the lift-off position, and averaged 3.8 kg. Although overall reliable refixation of the subscapularis was achieved by transosseous repair, almost 25% of patients showed signs of decreased function and 30% showed signs of partial defects. Subjective and objective functional deficits had a significant influence on the clinical outcome.