Characterization of progression of pelvic osteolysis after cementless total hip arthroplasty: computed tomographic study.

A retrospective analysis of 63 primary total hip arthroplasty cases was done using repeated computed tomography scans to evaluate the pelvic osteolytic lesions in early stage. The progression rate of osteolysis of hips with small osteolytic volume less than 766.97 mm(3) in initial CT was 85.82 mm(3)/year, and that of hips with osteolysis more than 766.97 mm(3) was 456.3 mm(3)/year (P < 0.001). Younger patients less than 52 years old with good Harris Hip Scores (more than 80) frequently showed much faster progression in volume of osteolytic lesions. The rate of osteolysis was accelerated when the amount of osteolysis reached a certain threshold volume in active young patients in a cascade manner even in early stage.