Serum endotoxin, tumor necrosis factor, and interleukin-6 response to total hip arthroplasty

The purpose of this study was to determine if endotoxin, tumor necrosis factor (TNF), and interleukin 6 (IL-6) increased in patients during or after total hip arthroplasty. Endotoxin is absorbed from the gut lumen and stimulates macrophages to make TNF. TNF is one of the stimuli for the increased production of IL-6. All three entities cause fever. If an increase takes place in any of the three, it could contribute to the commonly observed postop fever in total hip patients. Five serum samples were obtained from 12 patients: preoperatively; after the acetabular component was seated intraoperatively; in the recovery room; day 1 postoperatively; and day 3 postoperatively. IL-6 and TNF were measured using monoclonal antibody tests and endotoxin was measured with a chromogenic limulus amoebocyte lysate assay. A statistically significant increase in all three parameters was demonstrated. Endotoxin peaked intraoperatively or in the recovery room, TNF tended to peak in the recovery room, and the peak in IL-6 was more variable. Ten patients had a concomitant postoperative fever.