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.