Interleukin-6 in the blood of patients with total hip arthroplasty withoutloosening

Patients with total hip arthroplasty were screened for the presence of proi nflammatory cytokines in the systemic circulation. Only increased levels of interleukin-6 were detected in patients having had total hip arthroplasty more than 10 years ago. These increased levels of interleukin-6 were associ ated with a decrease in bone mineral density associated with polyethylene w ear and with radiologic osteolysis in some patients. These abnormalities we re not found in control subjects without total hip arthroplasty or in patie nts who had a prosthesis in place for less than 6 years. The elevation in i nterleukin-6 levels found in patients with the oldest prostheses could cons titute a marker for periprosthetic osteolysis.