title: Operative Mortality After Arthroplasty for Femoral Neck Fracture and Hospital Volume.
abstract: BACKGROUND
  The purpose of the present study is to use a statewide, population-based data set to identify mortality rates at 30-day and 1-year postoperatively following total hip arthroplasty (THA) and hemiarthroplasty (HA) for displaced femoral neck fractures. The secondary aim of the study is to determine whether arthroplasty volume confers a protective effect on the mortality rate following femoral neck fracture treatment.
  
  
  METHODS
  New York's Statewide Planning and Research Cooperative System was used to identify 45 749 patients older than 60 years of age with a discharge diagnosis of femoral neck fracture undergoing THA or HA from 2000 through 2010. Comorbidities were identified using the Charlson comorbidity index. Mortality risk was modeled using Cox proportional hazards models while controlling for demographic and comorbid characteristics. High-volume THA centers were defined as those in the top quartile of arthroplasty volume, while low-volume centers were defined as the bottom quartile.
  
  
  RESULTS
  Patients undergoing THA for femoral neck fracture rather than HA were younger (79 vs 83 years, P < .001), more likely to have rheumatoid disease, and less likely to have heart disease, dementia, cancer, or diabetes (all P < .05). Thirty-day mortality after HA was higher (8.4% vs 5.7%; P < .001) as was 1-year mortality (25.9% vs 17.8%; P < .001). After controlling for age, gender, ethnicity, and comorbidities, risk of mortality following THA was 21% lower (hazard ratio [HR] 0.79; P = .003) at 30 days and 22% lower (HR 0.78; P < .001) at 1 year than HA. Patients undergoing THA at high-volume arthroplasty centers had improved 1-year mortality when compared to those undergoing THA at low-volume hospitals (HR 0.55; P = .008).
  
  
  CONCLUSIONS
  Based on this large, population-based study, there is no basis to assume THA carries a greater mortality risk after hip fracture than does standard HA, even when accounting for institutional volume of hip arthroplasty.
authors.affiliation: Department of Orthopaedics, Center for Orthopaedic Population Studies, University of Rochester, Rochester, NY, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Maceroli
authors.affiliation: Department of Orthopaedics, Center for Orthopaedic Population Studies, University of Rochester, Rochester, NY, USA.
authors.forename: Lucas E
authors.initials: LE
authors.lastname: Nikkel
authors.affiliation: Department of Orthopaedics, Center for Orthopaedic Population Studies, University of Rochester, Rochester, NY, USA.
authors.forename: Bilal
authors.initials: B
authors.lastname: Mahmood
authors.affiliation: Department of Orthopaedics, Center for Orthopaedic Population Studies, University of Rochester, Rochester, NY, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Elfar
keywords: femoral neck fracture; fragility fracture; geriatric fracture; hemiarthroplasty; hip fracture; hospital volume; mortality; total hip arthroplasty