Management of the subscapularis contracture during shoulder arthroplasty for primary glenohumeral arthritis

Aim To evaluate the safety and effectiveness of a particular subscapularis release in shoulder arthroplasty for primary glenohumeral arthritis. Materials and methods Twenty-eight patients (19F, 9M) underwent shoulder arthroplasty for primary glenohumeral arthritis. Preoperative average Constant Score (CS) was 31.2 points (range 14–52), active anterior elevation (AAE) 92° (30–100°) and active external rotation (AER) 11° (−40 to 20°). During arthroplasty for subscapularis contracture, patients underwent subscapularis release freeing the superior tubular tendon (STT) with a section of the coracohumeral ligament (CHL) and the superior glenohumeral ligament (SGHL) and a deep release consisting of a section of the middle glenohumeral ligament (MGHL), very close to the glenoid labrum, and the inferior glenohumeral ligament (IGHL). An anatomic study was performed on 13 cadavers, verifying the structure of subscapularis tendon and its relationship with the capsule, the surrounding ligaments and the axillary nerve. Moreover, after having placed traction sutures on the subscapularis tendon, its lengthening was measured after STT release alone and after STT and deep release. The complete absence of neurological and vascular lesions was also verified. Results Average follow-up: 2.9 years. Postoperative mean CS was 70.5 (p〈0.005), with an absolute gain of 39.1. AAE increased from 92° to 142° (p=0.001) while AER increased from 8° to 48° (p=0.002). At the last follow-up, 19 patients (67.8%) were very satisfied, 5 patients (17.8%) were satisfied, 3 patients (10.7%) partially satisfied and 1 patient (3.5%) unsatisfied. In the anatomic control, the average lengthening of subscapularis tendon was 0.9 cm after STT release alone and 2.5 cm after STT and deep release. No vascular and neurological lesions were observed. Conclusions The subscapularis release during shoulder arthroplasty is extremely important to obtain the proper balance between anterior and posterior soft tissues and to achieve an optimal range of motion and joint stability. An adequate anatomical dissection could give good tendon mobilisation and lengthening, necessary for a good repair, and lead to a recovery of the range of motion, particularly for external rotation.