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Surgeons' attitudes toward surgery are the major source of area variation in use of knee replacement surgery

Rates of knee replacement surgery—an effective but expensive procedure—vary up to six-fold depending on geographic region. Surgeons' attitudes about knee replacement surgery as a solution to knee problems is the major source of area variation in the use of this surgery, concludes a study by the Total Knee Replacement Patient Outcomes Research Team (PORT), which was supported by the Agency for Healthcare Research and Quality (HS06432). Thus, changing surgeons' attitudes toward this procedure is the key to reducing regional variations in its use, according to PORT leader, Deborah A. Freund, Ph.D., M.P.H., formerly of Indiana University where PORT research was conducted. Dr. Freund is now at Syracuse University.

Dr. Freund and her colleagues examined the effect of several factors on county knee replacement rates in Ontario, Canada: characteristics and opinions of surgeons, family physicians, and rheumatologists; patients' severity of disease before knee replacement; access to knee replacement surgery; surgeons' use of other surgical treatment; and county population characteristics. After accounting for these factors, orthopedic surgeons' enthusiasm for the procedure was the dominant modifiable determinant of area variation. The researchers measured physician enthusiasm by their propensity to perform knee replacement and perceptions of expected outcome of the procedure, such as relief of pain, improved ability to walk, and complication rates.

The propensity of an individual orthopedic surgeon to perform knee replacement surgery was determined by adding the differences between how 34 patient characteristics affected that surgeon's decision to perform the surgery and the median responses of other surgeons. The propensity to operate was correlated with surgeons' perceptions about the operation's outcome and therefore explained 27 percent of the variance in county surgery rates. As expected, counties with older populations or the presence of teaching hospitals had higher per capita rates of knee replacement surgery. Patient severity of disease before knee replacement was not related to county variation in its use.

See "Physician enthusiasm as an explanation for area variation in the utilization of knee replacement surgery," by James G. Wright, M.D., M.P.H., Gillian A. Hawker, M.D., M.S.C., Claire Bombardier, M.D., and others, in Medical Care 37(9), pp. 946-956, 1999.

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