Radiographic parameters The stem alignment, acetabular cup abduction, anteversion angles and leg-length discrepancy were measured on digital anteroposterior (AP) pelvic radiographs. The radiographs were all obtained using a standardized technique with supine position, leg internally rotated and x-ray beam centered on pubic symphysis. For stem alignment, the investigators obtained proximal femoral axis, which was the line connecting centers of femoral canal at the levels of stem tip and lesser trochanter, and the femoral stem axis, which was the line connecting centers of femoral stem at levels of 2 centimeters and 5 centimeters proximal to the stem tip. The angle between proximal femoral axis and femoral stem axis was measured and analyzed as the stem alignment. The cup anteversion angle and abduction angle were means measured using AGFA IMPAX Orthopaedic Tool (Agfa Healthcare, Mortsel, Belgium). The leg-length discrepancy was the distance between the two lines from each lesser trochanter parallel to the inter-teardrop line.