Investigators prospectively evaluate the accuracy of intraoperative stem anteversion in 40consecutive total hip arthroplasties.

In all hips, investigators measure femoral stem anteversion postoperatively with three-dimensional computed tomography reconstruction of the femur, using both the distal femoral epicondyles and the posterior femoral condyles to determine the femoral diaphyseal plane. And investigators compare the surgeon's estimate of intraoperative stem version and stem version of CT scan.

Inclusion Criteria:

• Investigators recruited 40 consecutive patients who underwent THR between October 2015 and December 2015

Exclusion Criteria:

• patients who could not extend the hip because of a residual flexion contracture.

who had a flexion contracture of the knee or who could not flex the hip to 90° even after THR were excluded because participants could not adopt the posture required for the particular radiographs and CT scans.

Between October 2015 and December 2015, 40 consecutive patients who underwent primary cementless total hip arthroplasty agreed to undergo a postoperative computed tomography scan.