Introduction: The aim of the study was to investigate the reproducibility and accuracy of templating total hip arthroplasty with on-screen digital radiographs using three commercially available software packages, and compare the results to templating on-screen using acetates.

Method: In twenty patients undergoing hybrid total hip arthroplasty, pre-operative templating for acetabular size, femoral offset and stem size were performed by three independent observers using on-screen digital radiographs by three different techniques. The magnification of the on-screen images were adjusted appropriately by using a metal coin marker of known size attached to the patient at time of acquiring the radiographs. These images were used to template for total hip arthroplasty using three commercially available digital templating software packages (Orthoview™ Workstation, Southampton, UK, Ferrania LifeWeb TraumaCad™, Berkshire, UK and mdesk™ software suite, RSA Biomedical, Sweden). The templated results were compared with the component sizes subsequently implanted and to templating on-screen using acetates. Intra- and inter-observer reproducibility were assessed using the Intraclass Correlation Coefficient (ICC).

Results: Intra-observer reproducibility was good for the three software systems with almost all ICC values > 0.70. Inter-observer reproducibility was less consistent, which may reflect familiarity and may improve with a “learning curve”. All three software systems tended to slightly undersize the acetabular size.

Discussion: For both reproducibility and accuracy, all the three commercial systems were comparable with templating using the acetate template method. Digital templating using software packages is an acceptable method of templating. Templating software packages are certainly an attractive proposition but until installation & maintenance costs are reduced, “traditional” templating with acetates remains the most effective option.