Spotlight on Research for 2005

January 2005

Experience Is Key for Total Knee Replacement Outcomes

A new study funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases suggests a positive relationship between surgeons and hospitals performing a high volume of total knee replacements (TKR) and the outcomes for these interventions. The study found that patients of surgeons who perform 50 or more TKRs per year had a lower incidence of morbidity and postoperative complications than those whose doctors do 12 or less. Also, hospitals with 200 or more TKRs per year demonstrated similar positive outcomes in contrast to facilities that do less than 25 procedures per year.

The study research team, headed by Jeffrey N. Katz, M.D., M.S., analyzed 80,904 claims of Medicare patients who had primary or revision TKR between January 1 and August 31, 2000. The team determined the rates for mortality and complications for the first 90 days after the surgery. Complications included: deep wound infection requiring surgical attention or removal of prosthesis, pulmonary embolus, acute myocardial infarction, or pneumonia requiring hospitalization. The data were adjusted for age, gender, comorbid conditions, Medicaid eligibility (a marker of low income) and arthritis diagnosis.

TKR is a relatively low-risk surgical procedure in terms of 90-day rates of mortality and adverse events, when performed by an experienced surgeon in an experienced hospital. Most of the findings in this study are consistent with those reported in literature on associations between procedure volume and outcome for hip replacements and other surgical procedures. Of the 80,904 patients in the sample, 0.6 percent died, 0.8 percent had an acute myocardial infarction, 0.8 percent had a pulmonary embolus, 0.4 percent had a deep wound infection and 1.4 percent were hospitalized for pneumonia.

The mission of the NIAMS, a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information Clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at

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Katz, JN, et al. Association between hospital and surgeon procedure volume and outcome of total knee replacement. Journal of Bone and Joint Surgery 2004;86-A(9): 1909-1916.