BACKGROUND: Aseptic prosthetic loosening is known to be an inflammatory, cellular process. We hypothesized that the synovial cell count would significantly differ among normal controls, patients with aseptic loosening, and patients with other etiologies of aseptic failure after total knee arthroplasty and thus that the cell count would be useful in the diagnosis of aseptic loosening.
METHODS: Over a six-year time period, all patients undergoing revision total knee arthroplasties at our institution underwent prospective intraoperative aspiration by the two senior authors. Each patient was assigned to a failure category on the basis of a priori criteria: aseptic loosening, periprosthetic infection, component wear, periprosthetic fracture, component malposition, instability, stiffness, and extensor mechanism failure.
