The objectives of this study are to compare digital with manual templating in preoperative planning for total hip arthroplasty and to assess the usability of digital templating.

Conventional and digital radiographs performed prior to hip arthroplasty in forty one patients. Preoperative templating was performed by four independent observers with manual and digital templates on a Picture Archiving and Communication System (PACS) workstation. In all cases, acetabular cup, femoral stem sizes and length of femoral neck were measured. Intra- and interobserver agreement and predictability of real component size were calculated with weighted kappa analysis and Mann-Whitney test.

For acetabular cup and femoral stem size, inter- and intraobserver agreement was substantial, nevertheless, for length of femoral neck, it was poor in both methods. Comparing with the real size, digital templating method showed statistically significant predictability for acetabular cup size (p=0.001). However, there was no significant difference in femoral stem size and the length of femoral neck by both methods (p=0.074, p=0.140).

Both inter- and intraobserver agreement was similar. However, considering advantage of PACS system and superior predictability of digital templating technique, we recommend the preoperative digital templating in hospital with PACS system.