Posterior shoulder instability – A systematic review and meta-analysis of glenoid osteotomy and bone block procedures

Background: Osseous glenoid surgery for posterior shoulder instability is a low-volume, high-complexity procedure. Consequently, evidence is limited to small case series from a specialist center. This study aims to systematically review and meta-analyze the effectiveness and complications profile of glenoid osteotomy and bone block procedures in treating posterior shoulder instability. 

Methods: A systematic search in MEDLINE and Embase identified studies involving adult patients undergoing bone block or glenoid osteotomy. Two reviewers screened and extracted data, including patient demographics, surgery types, recurrence rates, complications, and patient-reported outcomes. The methodological quality of each study was evaluated. Meta-analysis was conducted on the reported proportion of recurrence and complications. 

Results: Twenty-four studies met the inclusion criteria, with over 300 patients in both osteotomy and bone block groups. The osteotomy group was more predominantly male, younger, with increased retroversion and bilateral symptoms. Rates of symptomatic recurrence were 18% (95% CI: 4, 19) for glenoid osteotomy and 11% (8, 31) for bone block group. Postoperative degenerative change was found in 5% (0, 16) and 8% (1, 18), respectively. Fracture rate was 2% (0, 8) for the osteotomy, and graft lysis rate was 12% (1, 30) for the bone block. Patient-reported outcome reporting was highly heterogenous and could not be synthesized. 

Conclusion: Both glenoid osteotomy and bone block procedures can successfully address symptomatic posterior shoulder instability. However, due to the considerable recurrence and complication profile, careful patient selection and consideration of centralized service delivery is warranted. The study underscores the need for further research in developing specialized, patient-centric interventions and emphasizes the importance of comprehensive outcome assessments for effective management of posterior shoulder instability.