title: Total knee arthroplasty outcomes in top-ranked and non-top-ranked orthopedic hospitals: an analysis of Medicare administrative data.
abstract: OBJECTIVE
  To examine outcomes of Medicare enrollees who underwent primary total knee arthroplasty (TKA) in top-ranked orthopedic hospitals identified through the U.S. News & World Report hospital rankings and 2 comparison groups of hospitals.
  
  
  METHODS
  We used Medicare Part A data to identify patients who underwent primary TKA between January 1, 2006, and December 31, 2006, in 3 groups of hospitals: (1) top-ranked according to U.S. News & World Report rankings; (2) not top-ranked, but eligible for ranking; and (3) not eligible for ranking by U.S. News & World Report. We compared the demographics and comorbidity of patients treated in the 3 hospital groups. We examined rates of postoperative adverse outcomes--a composite consisting of hemorrhage, pulmonary embolism, deep vein thrombosis, wound infection, myocardial infarction, or mortality within 30 days of surgery. We also compared 30-day all-cause readmission rates and hospital length of stay (LOS) across groups.
  
  
  RESULTS
  Our cohort consisted of 48 top-ranked hospitals (performing 10,477 primary TKAs), 288 eligible non-top-ranked hospitals (28,938 TKAs), and 481 hospitals not eligible for ranking (25,297 TKAs). Unadjusted rates of the composite outcome were modestly higher for top-ranked hospitals (4.3%, 455 patients) as compared with non-top-ranked hospitals (4.1%, 1191 patients) and hospitals ineligible for ranking (3.3%, 843 patients) (P<.001), but these differences were no longer significant after accounting for differences in patient complexity. Likewise, there were no significant differences in readmission rates or LOS across groups.
  
  
  CONCLUSIONS
  Rates of postoperative complications and readmission and hospital LOS were similar for Medicare patients who underwent primary TKA in top-ranked and non-top-ranked hospitals.
authors.affiliation: Division of General Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA. peter-cram@uiowa.edu
authors.forename: Peter
authors.initials: P
authors.lastname: Cram
authors.forename: Xueya
authors.initials: X
authors.lastname: Cai
authors.forename: Xin
authors.initials: X
authors.lastname: Lu
authors.forename: Mary S
authors.initials: MS
authors.lastname: Vaughan-Sarrazin
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Miller
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods; D005260:Female; D006782:Hospitals, Special / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D006278:Medicare; D009985:Orthopedics; D011183:Postoperative Complications / Q000453:epidemiology*; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology