title: Primary vs Conversion Total Hip Arthroplasty: A Cost Analysis.
abstract: BACKGROUND
  Increasing hip fracture incidence in the United States is leading to higher occurrences of conversion total hip arthroplasty (THA) for failed surgical treatment of the hip. In spite of studies showing higher complication rates in conversion THA, the Centers for Medicare and Medicaid services currently bundles conversion and primary THA under the same diagnosis-related group. We examined the cost of treatment of conversion THA compared with primary THA. Our hypothesis is that conversion THA will have higher cost and resource use than primary THA.
  
  
  METHODS
  Fifty-one consecutive conversion THA patients (Current Procedure Terminology code 27132) and 105 matched primary THA patients (Current Procedure Terminology code 27130) were included in this study. The natural log-transformed costs for conversion and primary THA were compared using regression analysis. Age, gender, body mass index, American Society of Anesthesiologist, Charlson comorbidity score, and smoker status were controlled in the analysis. Conversion THA subgroups formed based on etiology were compared using analysis of variance analysis.
  
  
  RESULTS
  Conversion and primary THAs were determined to be significantly different (P<.05) and greater in the following costs: hospital operating direct cost (29.2% greater), hospital operating total cost (28.8% greater), direct hospital cost (24.7% greater), and total hospital cost (26.4% greater).
  
  
  CONCLUSIONS
  Based on greater hospital operating direct cost, hospital operating total cost, direct hospital cost, and total hospital cost, conversion THA has significantly greater cost and resource use than primary THA. In order to prevent disincentives for treating these complex surgical patients, reclassification of conversion THA is needed, as they do not fit together with primary THA.
authors.affiliation: University of California Irvine Medical School, Irvine, California.
authors.forename: Garwin
authors.initials: G
authors.lastname: Chin
authors.affiliation: University of California Irvine Medical School, Irvine, California.
authors.forename: David J
authors.initials: DJ
authors.lastname: Wright
authors.affiliation: Department of Orthopaedic Surgery, Sorasky Medical Center, Tel-Aviv, Israel.
authors.forename: Nimrod
authors.initials: N
authors.lastname: Snir
authors.affiliation: Division of Adult Reconstruction, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, NYU Langone Medical Center, New York, New York.
authors.forename: Ran
authors.initials: R
authors.lastname: Schwarzkopf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000191:economics*; D003365:Costs and Cost Analysis; D005260:Female; D006620:Hip Fractures / Q000191:economics / Q000601:surgery*; D017721:Hospital Costs; D006801:Humans; D008297:Male; D006278:Medicare / Q000191:economics*; D008875:Middle Aged; D013997:Time Factors; D014481:United States
keywords: conversion total hip arthroplasty; cost; implant cost; primary total hip arthroplasty; revision total hip arthroplasty