Background: There are limited population-based data on the utilization and outcomes of total knee replacement. The aim of the present study was to describe the rates of primary and revision total knee replacement and selected outcomes in persons older than sixty-five years of age in the United States.
Methods: Using Medicare claims, we computed annual incidence rates of unilateral elective primary and revision total knee replacement among United States Medicare beneficiaries in the year 2000. Poisson regression was used to assess the relationships between demographic characteristics and the incidence rates of primary and revision knee replacement. Proportional hazards models were used to examine the relationships between the ninety-day rates of complications and demographic and clinical factors.
Results: The rate of primary knee replacement was lower in blacks than in whites and in those qualifying for Medicaid supplementation than in those with higher incomes. The complications observed during the ninety days following primary knee replacement included mortality (0.7%), readmission (0.9%), pulmonary embolus (0.8%), wound infection (0.4%), pneumonia (1.4%), and myocardial infarction (0.8%). The complications observed during the ninety days following revision knee replacement were mortality (1.1%), readmission (4.7%), pulmonary embolus (0.5%), wound infection (1.8%), pneumonia (1.4%), and myocardial infarction (1.0%). Blacks had higher rates of mortality, readmission, and wound infection after primary knee replacement than whites did. Patients who qualified for Medicaid supplementation had higher complication rates, particularly after primary knee replacement.
Conclusions: Overall, the rates of postoperative complications during the ninety days following total knee replacement are low. In the United States, blacks and individuals with low income undergo total knee replacement less frequently and generally have higher rates of adverse outcomes following primary knee replacement.
Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.
Note: The authors thank Robert A. Lew, PhD, for contributing to the design of the study.
Investigation performed at the Section of Clinical Sciences and the Division of Rheumatology, Immunology and Allergy, the Robert Brigham Arthritis and Musculoskeletal Clinical Research Center, Boston, Massachusetts; the Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; the Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts; the Departments of Medicine and Community Medicine, Dartmouth Medical School, Lebanon, New Hampshire; and the Musculoskeletal Health and Arthritis Program, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada
In support of their research or preparation of this manuscript, one or more of the authors received grants or outside funding from the National Institutes of Health (P60 AR 47782 and K24 AR 02123). None of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
- Copyright © 2005 by The Journal of Bone and Joint Surgery, Incorporated
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