Acromial Stress Fractures: A Systematic Review

Background: Acromial stress fracture (ASF) is a unique complication of reverse shoulder arthroplasty (RSA) that can have substantial influence on clinical results. The purpose of this review is to describe demographics, functional outcomes, and unio‎n rates for cases of RSA complicated by ASF. Methods: A systematic review was conducted using Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA) methodology to identify studies that reported results of RSA complicated by ASF. Searches were performed using PubMed and Scopus up to January 1, 2018. Five articles met inclusion and exclusion criteria. Results: ASF occurred in 61 (6.9%) of 874 RSA cases identified. 82% of patients who sustained an ASF were female. ASF cases were, on average, 7 years older than cases that were not complicated by ASF. While improved compared to their preoperative state, patients who sustained an ASF demonstrated significantly less improvement in pain, function, and ROM compared to RSA patients without ASF. Conclusion: Women and older patients appear to be at greater risk for an ASF after RSA. Though nonunio‎n rates are high, fair outcomes can still be achieved in cases of ASF after RSA. Further study is needed to identify modifiable and non-modifiable risk factors associated with the development of ASF. Level of evidence: IV