Abstract

Four hundred eighty-seven porous-coated anatomic (PCA) total arthroplasties were performed by the same surgeon between January 1982 and December 1989. Forty-three patients developed an effusion, pain, or decreased range of motion after a period of pain-free function. Average time to onset of symptoms was 4.5 years. Joint fluid aspirations were sterile and revealed the presence of high-density polyethylene crystals, best seen under a polarizing microscope. Thirty-three of these patients were arthroscopically evaluated. Extensive polyethylene wear and delamination were identified. Wear was most extensive on the medial tibial plateau. Patellar polyethylene wear was also identified. Substantial femoral component abrasions were present in areas where exposure of the tibial and patellar base plates had occurred. Diffuse granulomatous synovial tissue revealed an extensive foreign-body giant-cell reaction to polyethylene particles. In all patients, temporary symptomatic relief was obtained after arthroscopy. Thirty-two patients have, subsequently, had revision surgery. Intraoperative findings and biopsies at the time of revision confirmed the arthroscopic observations. Arthroscopy allowed the accurate diagnosis of polyethylene wear, provided temporary symptomatic relief, and facilitated preoperative revision planning. Polyethylene wear in PCA total knee replacements was related to patient characteristics (larger, younger, more active patients), nonconforming femotibial articular surfaces, thin polyethylene, heat-pressed polyethylene, and nonrigid mechanical attachment of polyethylene to metal base plate. Younger, more active, larger patients with total knee arthroplasties should be observed closely for evidence of polyethylene wear.