Posterior open wedge glenoid osteotomy provides reliable results in young patients with increased glenoid retroversion and posterior shoulder instability

PURPOSE: The relationship between posterior shoulder instability and increased glenoid retroversion has been documented. Posterior open wedge glenoid osteotomy is a possible treatment option for patients with increased glenoid retroversion, but outcomes in the literature are limited. Therefore, the purpose of this study was to report the clinical and radiological outcomes following posterior glenoid osteotomy.

METHODS: Patients that underwent posterior glenoid osteotomy for posterior shoulder instability with a GR angle of more than or equal to 10°, and were at least 12 months out from surgery, were included in the study. General data, medical history, and radiographic data such as the pre- and postoperative glenoid retroversion angle were extracted from the patients' hospital documentation notes. To evaluate the postoperative outcome, the Rowe standard rating scale for shoulder instability and the Oxford shoulder instability score were collected retrospectively.

RESULTS: A total of 12 shoulders (11 patients) could be included. The mean pre-operative glenoid retroversion was 23.3° (range 12°-35°) and this reduced significantly (p = 0.003) to a mean of 13° (range 1°-28°) postoperatively. At a mean follow-up of 19.8 months (range 14-36), the median Rowe score was 90 points (range 45-100 points) and the median Oxford instability score was 44 points (range 21-48 points). There were no postoperative re-dislocations or revision surgeries; however, one patient reported signs of recurrent shoulder instability and four asymptomatic glenoid neck fractures occurred.

CONCLUSION: Open wedge posterior glenoid osteotomy provides reliable clinical results with a low rate of clinical failure in a stringently selected patient cohort at short-term follow-up. However, due to the risk of potentially severe complications, we advocate this procedure for experienced shoulder surgeons only, who are familiar with its anatomical and technical considerations.

LEVEL OF EVIDENCE: IV (case series).