Inferior surgical outcomes following reverse total shoulder arthroplasty for nonunion and malunion compared to acute arthroplasty: a nationwide matched cohort analysis

Abstract

BackgroundReverse total shoulder arthroplasty (rTSA) has become popularized in the management of acute proximal humerus fractures (PHFs). Limited evidence exists to compare the outcomes of acute rTSA to management following failed open reduction and internal fixation. We aimed to analyze the differences between acute rTSA for PHF compared to subsequent rTSA for nonunion/malunion. MethodsPatients who underwent primary rTSA from 2016 to 2020 were identified in the Premier Healthcare Database. Nonunion, malunion, and hardware complication patients were identified using International Classification of Diseases Tenth Revision diagnosis codes and compared to acute PHF controls. Patients were matched in a 1:1 fashion to acute fracture based on age (±3 years), sex, race, and presence of pertinent comorbidities. Patient demographics, hospital factors, patient comorbidities, and 90-day complications were assessed and compared between the two cohorts. Descriptive statistics and regression analysis were employed with significance set at P < .05. ResultsPrior to matching, 8561 nonunion/malunion cases and 11,134 acute rTSA controls were identified. Patients undergoing acute rTSA for PHF were older, had longer length of stay, and higher total costs (P < .0001). When compared to acute rTSA for fracture, nonunion/malunion patients were at increased risk of multiple surgical complications including periprosthetic joint infection (odds ratio [OR]: 4.56; 95% confidence interval [CI]: 2.95-7.04; P < .0001), periprosthetic fracture (OR: 2.86; 95% CI: 2.09-3.93), stiffness (OR: 2.01; 95% CI: 1.17-3.44; P = .01), and dislocation (OR: 2.37; 95% CI: 1.80-3.12; P < .0001). However, patients undergoing acute rTSA had higher rates of all medical complications investigated, including deep vein thrombosis, pulmonary embolism, pneumonia, myocardial infarction, acute kidney infection, and sepsis (P < .001). ConclusionrTSA after nonunion/malunion of PHFs is associated with increased risk of surgical complications compared to acute rTSA. Initial rTSA for PHFs may mitigate subsequent increased risk of surgical complication and should be considered as the initial treatment option in patients with PHFs. However, the increased risk of medical complications seen in acute PHF warrants attention and diligent medical optimization from providers.