DIGITAL TEMPLATING FOR TOTAL HIP AND KNEE ARTHROPLASTY- ACCURACY OF THE ORTHOVIEWTM SYSTEM

Abstract

Background: The role of digital radiography has evolved consistently over the last decade. In many European hospitals, radiographs have been completely digitised and have moved to Picture Archiving and Communications System (PACS). Pre-operative templating for arthroplasty has been a major problem with using the system.

Aims: We investigate the accuracy of the OrthoviewTM software in templating for hip and knee arthroplasty.

Methods: A retrospective review of 20 Stryker-Exter hip and 20 Biomet- Vanguard knee arthroplasties were carried out. Anonymised preoperative radiographs were reviewed by experienced orthopaedic surgeons blinded to the purpose of the study. Templated component sizes were compared with actual implant sizes used at surgery. All radiographs were digitised on Kodak Car-estream PACS. Five surgeons were asked to separately review the radiographs to avoid intra-observer error.

Results: In templating for hip arthroplasty, Orthoview TM was 80% accurate in predicting the femoral stem size within one size of the actual component used. It also predicted the offset with 100% accuracy. In 90% of the patients, the actual head implant was within one size of the templated head. The system was able to predict the acetabular component size in only 30%. In knee arthroplasty, OrthoviewTM was 80% accurate within one size of the actual component used for the femur and 90% for the tibia.

Discussion: Digital radiographs have several well documented advantages over traditional radiographs. Orthoview TM enables the flexibility of digitised films to be used for pre-operative templating. It is reasonably accurate in prediction of femoral component size in both hip and knee arthroplasty and tibial size in knee arthroplasty. It is considerably less useful for acetabular sizing. Surgeons have to keep this variability in mind until more accurate systems are available.