Until the introduction of arthroscopic-assisted surgery for rotator cuff repair, the frequency of subscapularis tears was underestimated. These tears remain challenging to treat even with arthroscopy. The absence of a specific classification system has hampered communication about the treatment and outcomes of the various types of subscapularis tears. The objective of this prospective multicentre study was to validate the relevance of arthroscopic subscapularis tendon repair based on an assessment of short-term outcomes according to the initial extent of the anatomic lesions.

A prospective multicentre study sponsored by the French Society for Arthroscopy was conducted from March 2010 to January 2011 in 208 patients with subscapularis lesions that were either isolated or associated with limited anterosuperior tears. The Constant and UCLA scores were used to assess clinical outcomes. Anatomic and prognostic results were evaluated based on the physical examination, preoperative and postoperative imaging study findings, and anatomic lesions. Clinical data were available for 103 patients after at least 1year of follow-up and radiological data for 129 patients after at least 6months.

The preliminary clinical results in 103 patients with at least 1year of follow-up showed overall statistically significant improvements in the Constant and UCLA scores, with resolution of the clinical manifestations. The degree of improvement seemed to increase over time. The clinical results varied significantly across patient groups based on a classification system distinguishing four lesion types. Postoperative imaging studies to assess the anatomic results in all patients with at least 6months of follow-up (n=129) showed tendon healing in 92% of cases but also indicated muscle wasting of the upper subscapularis muscle in 18.6% of cases and increased fatty degeneration of the muscle belly.

Our study confirms the good clinical and radiological results reported in the literature. Our classification system distinguishing four lesion patterns was applicable during the imaging workup. The main finding from this classification system was the difference in results between Type 2 and Type 3 lesions. The trend towards improvements over time requires confirmation by longer-term studies, which will also have to establish that the increased wasting of the upper subscapularis muscle and fatty degeneration of the muscle belly have no adverse effects.

Level 3.