Macromotion of the femoral component in artificial hip joint.

Macromotion of the femoral component was analyzed in seven loose hips associated with six patients utilizing the manual compression and distraction test. The mean vertical and varus movement of these hips were 6.4 mm and 1.2 degrees, respectively. Out of a total 120 cementless total hip arthroplasties, there was no macromotion in the control group of six patients with moderate to severe thigh pain. There was also no relationship between macromotion and the severity of thigh pain. Micromotion or rotational instability, which could not be analyzed by conventional stress radiograms, may contribute substantially to thigh pain.