Risk factors for acromial and scapular fractures following reverse shoulder arthroplasty: a meta-analysis of over 100,000 shoulders.

Background: Stress acromial fractures (AF) and scapular spine fractures (SSF) are rare but challenging complications of reverse total shoulder arthroplasty (rTSA). The purpose of our study was to identify risk factors of AF and SSF after rTSA through a detailed systematic review of published literature. Methods: A systematic review of PubMed, Scopus, Web of Science, and Cochrane Library was conducted from inception to October 2023. We included all peer-reviewed studies investigating the risk of AF and SSF after rTSA, excluding biomechanical studies. A total of 1,047 publications were reviewed, and 25 publications with a total of 100,205 shoulders met our inclusion criteria. A meta-analysis of these publications was conducted using Comprehensive Meta-Analysis software. Odds ratios (OR) and 95% confidence intervals were used to estimate risks for categorical variables (gender, osteoporosis, inflammatory arthritis, and surgical history). Mean differences (MD) and standard deviations were used to determine the effect of continuous variables, such as age and body mass index (BMI). Results: The pooled reported rate of AF and SSF was 2%. Our analyses identified a higher risk of AF and SSF in patients with osteoporosis (OR = 2.33, Conclusion: Patients who suffered AF or SSF after rTSA were older with lower BMI. Other risk factors identified included osteoporosis, inflammatory arthritis, female gender, and previous rotator cuff repair. There is, however, a need for further investigations into additional crucial factors, such as prosthesis type and design and lateralization of components, as these variables could significantly influence complication rates and patient outcomes following rTSA.