Does the critical shoulder angle decrease after acromioplasty? A systematic review and meta-analysis

BACKGROUND: Rotator cuff tears are one of the most common shoulder injuries in the older population. This study aimed to determine whether acromioplasty reliably decreases the critical shoulder angle (CSA) and describe any associated complications. METHODS: A systematic literature review was performed according to PRISMA guidelines using PubMed, EMBASE, Web of Science, and Cochrane Library Database. Two reviewers independently screened the titles and abstracts using prespecified criteria. Studies where the acromioplasty was performed as a surgical procedure were included. Patient characteristics and degree of CSA reduction were collected from each individual study. All statistical analyses were performed using Review Manager (RevMan) 5.4.1 software. A random-effects model was used for meta-analysis. RESULTS: A total of 9 studies involving 1236 patients were included in the meta-analysis. The age of patients ranged from 23 to 82 years. The follow-up period ranged from 12 to 30 months. Of the 9 studies, 8 (88.9%) were retrospective, 1 (11.1%) was prospective, 5 were comparative, and 4 were case series. The mean CSA was significantly reduced from 36.1° ± 4.6° to 33.7° ± 4.2 (p < 0.05). The meta-analysis showed an overall best estimate of the mean difference in pre- and postoperative CSA equal to 2.63° (95% confidence interval: 2.15, 3.11] (p < 0.00001). CONCLUSIONS: Acromioplasty can significantly reduce CSA, notably in cases of high preoperative CSA. In addition, the effect of lateral acromioplasty on the CSA was more significant compared to anterolateral acromioplasty. Acromioplasty was not associated with complications during the short-term follow-up. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13018-022-02927-7.