The utility of digital templating in Total Hip Arthroplasty with Crowe type II and III dysplastic hips.

With the superiority of digital imaging, conventional preoperative acetate templating is gradually being replaced by digital templating in total hip arthroplasty (THA). The purpose of this study was to assess the utility of digital templating for patients with Crowe type II and III dysplastic hips. In this study, 41 THA patients with Crowe type II or III dysplastic hips and 48 THA patients with other primary diseases were retrospectively reviewed. All patients were fitted with cementless prostheses in 2008. For the THA patients with dysplastic hips, we attempted to restore their hip centres to the position of the true acetabulum. Digital templating was the method chosen to achieve hip centre restoration. The prosthesis prediction accuracy (within ± one size using digital templating) was 20 (48.8%) for the cup size and 30 (73.2%) for the stem size. Meanwhile, for patients with other primary diseases, the accuracy for the cup size within ± one size was 34 (70.8%) and for the stem size accuracy was within ± one size in 38 (79.2%). Between the two patient groups, there was a significant difference in the predicted cup size. In patients with dysplastic hips, the low accuracy of the predicted cup size may have resulted from difficulty in predicting the vertical location of the hip centre. Despite this limitation, preoperative planning using digital templating is a convenient technique for THA patients with Crowe type II and III dysplastic hips.