Acromial Stress Fractures: A Systematic Review

Background: Acromial stress fracture (ASF) is a unique complication of reverse shoulder arthroplasty (RSA) thatcan have substantial influence on clinical results. The purpose of this review is to describe demographics, functionaloutcomes, and union rates for cases of RSA complicated by ASF.Methods: A systematic review was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology to identify studies that reported results of RSA complicated by ASF. Searches wereperformed 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 totheir 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 arehigh, fair outcomes can still be achieved in cases of ASF after RSA. Further study is needed to identify modifiable andnon-modifiable risk factors associated with the development of ASF.Level of evidence: IV