Polyethylene wear and synovitis in total hip arthroplasty - A sonographic study of 48 hips

Forty-six patients (48 hips), operated on with cemented total hip arthropla sty (THA) because of arthrosis, were examined radiographically and sonograp hically at 10-year follow-up. Polyethylene wear of acetabular cups was meas ured on conventional non-weight-bearing pelvic radiographs, and the volume of polyethylene debris was calculated. Radiographic signs of loosening were identified. The capsular distance (ie, thickness of the synovium or synovi al contents) was measured sonographically. We found a significant correlati on between increased volumetric wear and increased capsular distance. Hips with radiographically loose acetabular components had significantly greater volumetric wear and capsular distance than those without signs of acetabul ar loosening. This relationship was not observed in hips with radiographica lly loose femoral components. In cemented THA, the volume of polyethylene w ear debris and the thickness of the synovium and the synovial contents are related. In the event of radiographic loosening of the acetabular component , they are both increased.