The Arthroscopic Subscapular Sling Procedure Results in Low Recurrent Anterior Shoulder Instability at 24 Months Follow-Up.

PURPOSE: The purpose of this study was to analyze the results of the subscapular sling procedure developed for anterior shoulder instability in patients with less than 10 % anterior glenoid bone loss. The aim was to explore if this procedure would be successful in preventing recurrent shoulder dislocation.

METHODS: Patients were treated surgically with the arthroscopic subscapular sling procedure. A semitendinosus graft was used to reconstruct the anterior labrum and to establish a sling suspension around the upper part of the subscapularis tendon. The patients were followed by x-ray (12 and 24 months). Magnetic resonance imaging (MRI) of the shoulder region and clinical examinations were performed at 3, 12 and 24 months. Recurrent dislocation was the primary endpoint. The Western Ontario Shoulder Instability Index (WOSI) and MRI results were secondary outcome measures. An independent physiotherapist assessed residual instability and ROM.

RESULTS: Fifteen patients were included with a dislocation rate of zero % after 24 months follow-up. There was a significant clinical improvement of the WOSI score from 57 % (904) at baseline to 88 % (241) at 24 months (p < 0.001). The proportion of patients with an improvement in the WOSI Total score larger than the estimated Minimal Clinically Important Difference (MCID) was 100% both at 12 and 24 months. MRI showed an intact sling in all patients. External rotation was not significantly reduced (52° at baseline vs 47° at 24 months, p = 0.211). Flexion and abduction were significantly improved from 152° to 174° (p=0.001) and 141° to 170° (p<0.001) after 24 months. The surgical procedures were completed without any intraoperative complications.

CONCLUSION: The subscapular sling procedure resulted in low recurrent shoulder instability and improved patient-reported outcome measures at 24-months follow-up.