The accuracy of preoperative templating in cementless total hip arthroplasty.

We evaluated the accuracy and clinical usefulness of preoperative templating in 109 cementless total hip arthroplasties. The size of the prosthesis was exactly predicted in 46 (42.2%) acetabular and 75 (68.8%) femoral components. The accuracy increased to greater than 90% if the prosthesis size was within 1 or 2 sizes (above or below) for femoral component and acetabular components, respectively. Having a contralateral total hip arthroplasty as a guide for preoperative templating was associated with greater accuracy in predicting the femoral component size only. Eighty-eight percent of the acetabular components were oriented inside the presumed safe range for inclination; 42% of the acetabular components were in the presumed safe range of anteversion. The mean postoperative leg length discrepancy was 0.9 +/- 6.8 mm; 93.5% had a discrepancy within 10 mm.