Methylmethacrylate monomer and fat content in shed blood after total joint arthroplasty.

Twenty-five patients were prospectively evaluated to quantify levels of methylmethacrylate monomer and fat in systemic blood and in shed blood after total joint arthroplasty. Levels of methylmethacrylate monomer in systemic blood were measured at intervals after insertion of the prosthesis. Levels of methylmethacrylate monomer in shed blood were measured at intervals after insertion of the drain. Levels of fat in systemic blood were measured preoperatively and 30 minutes after insertion of the prosthesis. Levels of fat in shed blood were measured 60 minutes after insertion of the drain. No significant fat or methylmethacrylate monomer was noted in systemic blood. Levels of methylmethacrylate monomer in shed blood were highest five minutes after insertion of the drain. Levels of methylmethacrylate monomer in shed blood collected from the hip were significantly lower than levels in shed blood from the knee. Levels of shed blood from the hip and knee were undetectable six hours after insertion of the drain. Shed blood from the hips and knees contained fat particles of three diameters: fat particles less than 9 microns, 9-40 microns, and greater than 40 microns. The diameter of most of the fat particles in the shed blood was less than 9 microns. Fat particles less than 40 microns in diameter will not be removed by microaggregate screen filters 40 microns in diameter.