Poster 160: Arthroscopic Anatomic Glenoid Reconstruction Does Not Affect Subscapularis Muscle Compared To Latarjet

OBJECTIVES: The Latarjet technique has been the gold standard treatment for glenoid bone loss following anterior shoulder instability due to its low recurrence rate, but other techniques including arthroscopic anatomic glenoid reconstruction (AAGR) have shown similar outcomes with fewer complications. The Latarjet requires a subscapularis split or take-down for placement of the coracoid, which may compromise post-operative subscapularis quality and strength. The AAGR is a subscapularis-sparing technique that obviates the need for a subscapularis split by using a far medial (Halifax) portal for graft placement. The purpose of this study was to compare subscapularis muscle changes before and after surgery between Latarjet and AAGR patients. METHODS: This study was a retrospective analysis of patients treated surgically with AAGR and Latarjet that had pre- and post-operative CT scans. Patients’ charts were reviewed to obtain demographic information, as well as CT scan cross-sectional area measurements of the subscapularis muscle on pre- and post-surgery scans. We used a pre-existing validated formula (volume=[0.06(A+C)]-13.02) for calculating the volume of the subscapularis pre- and post-operatively based on the cross-sectional area of the muscle. RESULTS: Our cohort included 40 patients in each group with pre- and post-operative CT scans. On average, patients had a CT scan one year post-operatively. Pre-operatively, patients were estimated to have similar subscapularis volumes (p>0.05). We found that the change in medial area of the subscapularis muscle was significantly higher in the Latarjet group (-325.8 mm2) compared to the AAGR group (-73.2 mm2) (p<0.05). We found that AAGR patients had a 3% increase in subscapularis volume post-operatively, while the Latarjet patients had 3% decrease in volume (p<0.05) CONCLUSIONS: The AAGR technique is subscapularis-sparing both in surgical technique and structural outcomes, resulting in comparable subscapularis cross-sectional area and volume pre- and post- operatively. Latarjet using a subscapularis split results in lower subscapularis medial volumetric area.