Bipolar femoral endoprosthesis: a study correlating component movement with clinical outcome

Fifty-five bipolar femoral hemiarthroplasties performed between January 1979 and February 1986 were reviewed to correlate component movement with clinical outcome. Fourteen of these patients were examined clinically using the Harris Hip Score and radiographically by the method of Drinker and Murray to determine the per cent of total motion in abduction present at the inner bearing surface. The average followup was 19.7 months. The data demonstrate that the clinical result is related to inner bearing motion. The inner bearing motion is significantly decreased by weight bearing and may be influenced by the size of the femoral component.