A PROSPECTIVE RANDOMISED CONTROLLED TRIAL OF COMPUTER ASSISTED VERSUS CONVENTIONAL TOTAL KNEE ARTHROPLASTY

Introduction The aim of this study was to compare the new technique of computer assisted knee arthroplasty (CAK) against the conventional jig based technique (JBK). Methods Seventy-five consecutive patients underwent knee replacement and were randomly allocated to either the CAK or JBK group. Post-operative CT scans were performed according to the Perth CT Knee Arthroplasty protocol to assess the accuracy of alignment. This measures seven parameters of alignment to an accuracy of one degree. Pre and post-operative Maquet views of the limb were also performed. Intra-operative soft tissue release together with post-operative pain scores and blood loss where also assessed. Results CT scans performed show a statistically significant improvement in component alignment when using computer assisted surgery for femoral varus/valgus (p=0.032),femoral rotation (p=0.001),tibial varus/valgus (p=0.047) tibial posterior slope (p=0.0001), tibial rotation (p=0.011) and femoraltibial mismatch (p=0.037). Standing Maquet limb alignment was also improved (p=0.004) as was blood loss (p=0.0001). CAK surgery took longer, a mean increase of 13 minutes (p=0.0001). Conclusions This is the first controlled study to assess all seven alignment characteristics of knee arthroplasty and use them to compare outcomes in conventional and computer assisted operations. It shows a clear improvement in component alignment with computer navigation. In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source