Acute Versus Delayed Reverse Shoulder Arthroplasty for the Primary Treatment of Proximal Humeral Fractures.

INTRODUCTION Reverse total shoulder arthroplasty (rTSA) is gaining popularity as a treatment option for proximal humeral fractures in elderly patients. The impact of surgical timing on outcomes of primary rTSA is unclear. This study compared the rates of revision and complication, and surgery day cost of treatment between acute and delayed primary rTSA patients. METHODS Elderly patients with proximal humeral fracture who underwent primary rTSA within a year of fracture were identified in a national insurance database from 2005 to 2014. Patients were separated into acute ( 4 weeks) cohorts based on the timing of rTSA. The univariate 1-year rates of revision and complication and surgery day cost of treatment were assessed. Multivariate logistic regression analysis was conducted, accounting for the factors of age, sex, obesity, diabetes comorbidity, and tobacco use. RESULTS Four thousand two hundred forty-five (82.6%) acute and 892 (17.4%) delayed primary rTSA patients were identified. Acute rTSA was associated with a higher surgery day cost (acute $15,770 ± $8,383, delayed $14,586 ± $7,271; P < 0.001). Delayed rTSA resulted in a higher 1-year revision rate (acute 1.7%, delayed 4.5%; P < 0.001) and surgical complication rates of dislocation (acute 2.8%, delayed 6.1%; P < 0.001) and mechanical complications (acute 1.9%, delayed 3.4%; P = 0.007). Multivariate analysis identified delayed primary treatment as independently associated with increased risk of revision (odds ratio: 2.29, 95% confidence interval 1.53 to 3.40; P < 0.001) and dislocation (OR: 2.05, 95% confidence interval 1.45 to 2.86; P < 0.001). CONCLUSION Delayed primary rTSA was associated with higher short-term rates of revision and dislocation compared with acute primary rTSA. Our results suggest that delaying rTSA, whether because of attempted nonsurgical treatment or patients' lack of access, may result in increased complication and additional surgery. LEVEL OF EVIDENCE Level III.