Effects of Bone Incorporation After Arthroscopic Stabilization Surgery for Bony Bankart Lesion Based on Preoperative Glenoid Defect Size

Background: Recurrent shoulder instability occurs more frequently after soft tissue surgery when the glenoid defect is greater than 20%. However, for lesions less than 20%, no scientific guidance is available regarding what size of bone fragments may affect shoulder functional restoration after bone incorporation. Purpose/Hypothesis: The purpose was to analyze how preoperative glenoid defect size and bone fragment incorporation alter postoperative clinical outcomes, we compared the functional outcomes of shoulders with and without bony Bankart lesion. It was hypothesized that differences in postoperative clinical outcomes between patients with and without bony fragments would be found only in patients with a larger glenoid defect. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 223 patients who underwent arthroscopic stabilization surgery for recurrent anterior shoulder instability were divided into two groups based on the presence of anterior glenoid bone fragments. In each group, postoperative shoulder functional outcomes, sports activity level, and recurrence rates were evaluated according to preoperative glenoid defect size (small, <10%; medium, 10%-15% and 15%-20%; large, >20%). Results: In patients with small or medium defects, no significant differences were found in postoperative clinical outcomes and sports activity levels between the two groups. However, in patients with a large defect, the patients with bone fragments (mean ± SD American Shoulder and Elbow Surgeons [ASES] score, 92.3 ± 2.7; Rowe score, 90.9 ± 5.4) showed significantly superior clinical outcomes compared with patients who did not have fragments (ASES score, 87.3 ± 6.2, P =.02; Rowe score, 84.8 ± 7.3, P =.04). Among patients without bone fragments, recurrence increased significantly with increasing preoperative glenoid defect size (recurrence rates: 0% in small defects, 7.4% in medium defects, 22.2% in large defects), whereas patients with bone fragments showed no tendency for increasing or decreasing recurrence rates (0% in small defects, 7.9% in medium defects, 5.9% in large defects). Conclusion: In the treatment of bony Bankart lesion, the effect of bone fragment incorporation was different according to preoperative glenoid defect size. In patients with preoperative glenoid defects less than 20% of the glenoid width, bone fragment incorporation after arthroscopic bony Bankart repair did not alter clinical outcomes, sports activity levels, or recurrence rates, whereas in patients with defects greater than 20% of the glenoid width, bone fragment incorporation improved clinical outcomes and recurrence rates.