Novel method to evaluate femoral head penetration in the polyethylene liner after total hip arthroplasty: three-dimensional evaluation on standing radiographs

The average three-dimensional penetration rate during the first 2 years after operation was markedly greater than the frontal two-dimensional penetration rate that was conventionally applied for postoperative evaluation. Three-dimensional evaluation using both frontal and sagittal radiographs is necessary to avoid undervaluation of the head movement after total hip arthroplasty.