The accuracy of digital templating: a comparison of short-stem total hip arthroplasty and conventional total hip arthroplasty.

PURPOSE: Selection of the correct femoral stem size is crucial in total hip arthroplasty for an uncomplicated implantation and good initial stability. Pre-operative templating has been shown to be a valuable tool in predicting the correct implant size. For short-stem total hip arthroplasty (SHA), which recently is increasingly used, it is unknown if templating can be performed as reliable as conventional total hip arthroplasty (THA).

METHODS: A total of 100 hip arthroplasties, 50 with SHA and 50 with THA, were templated by four orthopaedic surgeons each. The surgeons had different levels of professional experience and performed a digital template of the acetabular and femoral component on the pre-operative radiographs. The results were compared with the truly inserted implant size.

RESULTS: For the femoral stems the average percentage of agreement (± 1 size) was 89.0 % in SHA and 88.5 % in THA. There was no significant difference among surgeons in the accuracy of templating the correct stem size and no significant difference between templating SHA and THA. For the acetabular component the average percentage of agreement (± 1 size) was 75.8 %. However, the more experienced surgeons showed a significant higher accuracy for templating the correct cup size than the less experienced surgeons.

CONCLUSION: Digital templating of SHA can predict the stem sizes as accurately as conventional THA. Therefore digital templating is also recommendable for SHA, as it helps to predict the implant size prior to surgery and thereby might help to avoid complications.