PARTICULATE DEBRIS PRESENTING AS RADIOGRAPHIC DENSE MASSES FOLLOWING TOTAL KNEE ARTHROPLASTY

Two cases of failed total knee arthroplasty associated with significan t titanium debris that created massive radiographic densities are repo rted. The similarities of the failed total knee arthroplasties are tha t both involve titanium femoral components with failed metal-backed pa tellar components. At the time of surgical intervention, patellar poly ethylene dissociation from metal-backed patellar components was noted with excessive burnishing and wear of the remaining metal-backed patel lar component and of the titanium femoral component. Wear of the tibia l polyethylene was noted in both cases. The titanium-on-titanium wear couple produced significant debris, resulting in large mass formation about the total knee arthroplasty. Additionally, there were loculated, fluid-filled sacks of titanium debris. Histologic sections performed for both cases revealed significant deposits of titanium in combinatio n with polyethylene. In both cases, radiographs revealed the presence of large, radiodense masses. These cases illustrate that when consider ing etiologies for radiodense masses about total joint arthroplasty, p articulate titanium debris resulting in mass formation must be added t o the differential diagnosis.