Accuracy and Reliability of Preoperative Templating for Total Hip Arthroplasty

Preoperative onlay templating is prevalently used to determine the size and placement of acetabular and femoral components before total hip arthroplasty (THA). The purpose of this study was to determine the accuracy and reliability of preoperative onlay templating in uncemented THA. In a cross sectional study، 50 patients who underwent uncemented THA for hip osteoarthritis were selected in one teaching hospital، retrospectively. The study was done in a 4-month period. Using onlay templates، four surgeons determined the size of acetabular and femoral component on plain anteroposterior hip radiographs. Finally، the average percentage of agreement between template and implanted components were considered as the accurate representation. Kappa coefficient was utilized to determine the interobserver reliability. The accuracy of templating for acetabular and femoral component size was 60% and 59. 5%، and the interobserver reliability was 49% and 52%، respectively. Based on our findings، preoperative onlay templating cannot provide us with proper component selection and intraoperative determination of correct size is required for best outcome achievement.