Arthroscopic Subscapularis Augmentation With Xenograft Glenoid Bone Block in Patients With Recurrent Anterior Shoulder Instability.

Introduction: The purpose of this study was to investigate the clinical and radiographic outcomes at 2 years for patients who underwent an arthroscopic xenograft bone block procedure plus ASA for recurrent anteroinferior gleno-humeral instability. Methods: This retrospective study was conducted on patients affected by chronic anteroinferior shoulder instability. The inclusion criteria were as follows: patients must be aged 18 years or older; have recurrent anteroinferior shoulder instability, a glenoid defect >10%, assessment by the Pico area measurement system, anterior capsular insufficiency, and an engaging Hill-Sachs lesion. The exclusion criteria were as follows: multidirectional instability, glenoid bone defect <10%, arthritis, and minimum follow-up less than 24 months. Clinical outcomes were evaluated according to Western Ontario Shoulder Instability Index (WOSI) and Rowe scale. Computed tomography (CT) results were evaluated to assess any signs of resorption or displacement of the xenograft at 24 months follow-up. Results: Twenty patients that met all the inclusion criteria underwent arthroscopic xenograft bone block procedure and ASA. The mean preoperative Rowe score was 38.3 points, and it significantly improved (P < .001), increasing to 95.5 points. ROWE level at follow-up was excellent for 18 patients (90%), fair for 1 patient (5%), and poor for another patient (5%). The mean preoperative WOSI score was 1242 points, and it improved significantly (P <.0001), with a mean score of 120 points at follow-up. In all patients, the comparative study between CT scans performed postoperatively and at final follow-up did not reveal a volume reduction of the xenografts (P > .05) and absence areas affected by signs of resorption and breakage with 34.4% of postprocedural increase of the glenoid surface, were seen. Conclusions: The combination of ASA and bone block procedure with a xenograft was effective in the glenoid reconstruction and restoration of shoulder stability. No radiographic evidence of graft resorption, graft displacement, or glenohumeral arthritis were observed at 24-month follow-up. Level of Evidence: Level IV, therapeutic case series.