Despite the growing recognition of acromial stress fractures (ASFs) following reverse total shoulder arthroplasty (RTSA), much of the current data is derived from single-center studies with limited generalizability. This multicenter study investigated the incidence of ASFs after RTSA, and identified preoperative patient characteristics associated with their occurrence.
Using two institutional registries from different regions of the United States, we identified 1479 patients undergoing either primary or revision RTSA between 2013-2018 with minimum 3-month follow-up. ASFs were defined as radiographic evidence of an acromial or scapular spine fracture with clinical symptoms (e.g. tenderness over the acromion or scapular spine). Multivariable logistic regression was performed to identify preoperative patient factors associated with the development of ASFs.
Overall, 54 (3.7%) patients were diagnosed with an ASF after RTSA. Patient-related factors independently associated with the development of an ASF included female sex (OR, 2.21 reference: male; 95% CI, 1.03-4.74; P < 0.05), rheumatoid arthritis (OR, 2.30; 95% CI, 1.02-5.16; P < 0.05), osteoporosis (OR, 2.55; 95% CI, 1.24-5.21; P < 0.05), a diagnosis of degenerative joint disease (DJD) with rotator cuff tear (OR, 4.74 reference: DJD without rotator cuff tear; 95% CI 1.84-12.23; P < 0.05), and fracture malunion/nonunion (OR, 5.21; 95% CI, 1.20-22.76; P < 0.05) CONCLUSIONS: The non-negligible percentage of ASFs that occur after RTSA is associated with the diagnoses of rotator cuff dysfunction and chronic fracture sequelae in female patients with suboptimal bone health. This information can be used to counsel patients and set expectations about potential setbacks in recovery.
Level III; Retrospective Cohort Comparison; Treatment Study.

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