The accuracy of pre-operative digital templating in total hip arthroplasty performed in a low-volume, resource-constrained orthopaedic unit

Aims: Total hip arthroplasty (THA) is considered one of the most successful surgical procedures in modern medicine. The success of THA is well documented, and includes high patient satisfaction rates, low morbidity rates and cost-effective surgery. Most publications come from THA performed in high-volume arthroplasty units, done in high-income countries. Limited data is available on THA performed in low-volume, low-income countries. The aim of this study was to evaluate the accuracy of digital templating in a low-volume, resource constrained orthopaedic unit from 2016 to 2017. We introduced a standardised hip radiography programme, followed by a stepwise pre-operative templating method. We compared the implant sizes inserted during THA with the templated sizes determined pre-operatively. This was to deduct whether digital templating in a low volume arthroplasty unit is accurate and of the same value as digital templating done in a high-volume unit. Methods: A descriptive retrospective study was conducted on all patients who received elective primary uncemented THA in a low-volume, resource-constrained orthopaedic unit. Pre-operative radiographs were done according to guidelines published by Scheerlinck followed by pre-operative templating using the Impax Orthopaedic tools® software and a stepwise technique described by Bono. Implanted prosthesis sizes, as recorded in operation notes, were retrospectively compared to pre-operative templating. Results: A total of 56 participants were included (30 females, 26 males), with a mean age of 55.5 (32–78) years. On the acetabular side, in 71% (n=40; p<0.001) there was a cumulative difference of one implant size between the templated cup size and the actual cup size used. On the femoral side, in 79% (n=44; p<0.001) there was a cumulative difference of one implant size between the templated stem size and the actual stem size used. Oversizing of the implants was more prevalent, with 20% (n=11) of the acetabular components oversized by two or more sizes and 13% (n=7) of the femoral components oversized by two or more sizes. Conclusion: With the introduction of a standardised radiology programme and a stepwise templating technique, the benefits and accuracy of pre-operative templating done in a low-volume, resource-constrained orthopaedic unit is comparable to published data done in high-volume arthroplasty units. Level of evidence: Level 4