Titanium wear debris in failed cemented total hip arthroplasty. An analysis of 71 cases.

Overview

Seventy-one cemented total hip arthroplasties (THAs) were reviewed following removal of the all-titanium alloy femoral stem. Fifty-one hips were primary arthroplasties that failed due to aseptic loosening, 8 were previous revisions with aseptic loosening, and 12 were removed for infection. The average duration of service for the three groups was 4.5 years, 5.0 years, and 3.7 years, respectively. Femoral bone loss in aseptically loose, primary THA was graded as severe in 51%, moderate in 24%, and mild in 20%. Femoral endosteolysis was present in 94%, while acetabular osteolysis was seen in 6%. Histological evaluation of tissues from failed primary arthroplasties revealed polymethyl methacrylate debris in 75% of cases, polyethylene debris in 80%, metal debris in 75%, and chronic inflammatory cells in all cases. Metallic debris was not seen in the failed revision cases and in only 17% of the infected cases. Examination of retrieved femoral components revealed burnishing of the head in all cases, while 71% of stems with aseptic loosening were abraded from the cement. Metal levels from 12 cases averaged 2,111 mg/g of dry tissue (range, 60-11,823); synovial fluid levels from 8 other cases averaged 106 mg/l (range, 22-340). While it is not certain whether metallic particles are a primary cause of loosening or are generated secondarily, their presence seems to accelerate bone loss and loosening.