A comparison of total hip and knee replacement in specialty and general hospitals

Background: The emergence of specialty orthopaedic hospitals has generated widespread controversy, but little is known about the quality of care they deliver. Our objective was to compare the characteristics and outcomes of patients undergoing major joint replacement in specialty orthopaedic and general hospitals. Methods: We conducted a retrospective cohort study of 51,788 Medicare beneficiaries who underwent total hip replacement and 99,765 who underwent total knee replacement in thirty-eight specialty orthopaedic hospitals and 517 general hospitals between 1999 and 2003. We compared demographic data, rates of comorbid illness, and socioeconomic status of patients treated in specialty and general hospitals. Logistic regression was used to calculate the odds of an adverse outcome (death or selected surgical complications) after adjustment for patient characteristics and hospital procedural volume. Results: The demographic data and the ratio of primary to revision arthroplasties were similar, but patients who received care in specialty hospitals had less comorbidity and resided in more affluent zip codes than their counterparts in general hospitals in 2003. Specialty hospitals had significantly greater mean procedural volumes in 2003 than did general hospitals for both total hip replacement (thirty-three compared with twenty procedures; p = 0.05) and total knee replacement (seventy-five compared with forty procedures; p = 0.006). The unadjusted rate of adverse outcomes was lower in specialty hospitals than in general hospitals for total hip replacement (3.0% compared with 6.9%; p < 0.001) and total knee replacement (2.1% compared with 3.9%; p < 0.001). After adjusting for patient characteristics and procedural volume, the odds of adverse outcomes occurring were significantly lower for patients in specialty hospitals than for those in general hospitals for both primary joint replacement (odds ratio, 0.64; 95% confidence interval, 0.56 to 0.75; p < 0.001) and revision joint replacement (odds ratio, 0.49; 95% confidence interval, 0.36 to 0.66; p < 0.001). Conclusions: After adjustment for patient characteristics and hospital volume, the specialty orthopaedic hospitals had better patient outcomes, as measured by Medicare administrative data, than did the general hospitals. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.