Total knee arthroplasty outcomes in top-ranked and non-top-ranked orthopedic hospitals: An analysis of medicare administrative data

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. Patients and 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-topranked 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. Conclusion: 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.