Cellular immune responses to orthopaedic implant materials following cemented total joint replacement.

In vitro cellular immune responses to metallic and polymeric implant materials in particulate form were measured preoperatively in 185 patients. The patients were candidates for either primary total joint replacement (n = 65) or revision arthroplasty (n = 120). Proliferative cellular responses to polymethylmethacrylate particles in patients with osteoarthritis at revision surgery for aseptic loosening were significantly higher than the responses of patients with osteoarthritis at either primary surgery or surgical revision for mechanical failure of the prosthesis or sepsis. The responses to particles of cobalt-chromium alloy at revision surgery were also higher than the responses at primary surgery. The responses were reevaluated in 32 patients after a minimum of 10 months following surgery to correlate individual changes in the biological responses with clinical progress. Reevaluation at early follow-up of patients who had undergone primary surgery revealed significantly elevated proliferative responses and in vitro cytokine production in response to polymethylmethacrylate and cobalt-chromium alloy particles compared with their preoperative responses. In contrast, the response at follow-up to polymethylmethacrylate was significantly reduced in patients who had undergone revision surgery, and this reduction corresponded with a marked improvement in pain, joint motion, and function following revision surgery. These data suggest that specific cellular responses to polymethylmethacrylate or cobalt-chromium alloy particles, or both, may be associated with loose or painful prostheses.