Physician enthusiasm as an explanation for area variation in the utilization of knee replacement surgery

BACKGROUND. Explanations for regional variation in the use of many medical and surgical treatments is controversial. OBJECTIVES. TO identify factors that might be amenable to intervention, we investigated the determinants of regional variation in the use of knee repl acement surgery. RESEARCH DESIGN. We examined the effect of the following factors: character istics and opinions of surgeons; family physicians and rheumatologists; pat ients' severity of disease before knee replacement; access to knee-replacem ent surgery; surgeons' use of other surgical treatment; and county populati on characteristics. OUTCOMES MEASURE. County utilization rates of knee replacement in Ontario, Canada. RESULTS. Counties that had higher rates of knee replacement had older patie nts (P = 0.0001), higher percentage of medical school affiliated hospital b eds (P = 0.04), with more male (P = 0.02) non-North American trained referr ing physicians (P = 0.002) and orthopedic surgeons who had higher propensit ies to operate and better perceptions of outcome (P = 0.0001). CONCLUSIONS. After controlling for population characteristics and access to care (including the number of hospital beds, and the density of orthopaedi c and referring physicians), orthopaedic surgeons' opinions or enthusiasm f or the procedure was the dominant modifiable determinant of area variation. Thus, research needs to focus on the opinions of surgeons which may be imp ortant in reducing regional variation for knee replacement.