Abstract
Accurate implant alignment, prolonged operative times, array pin site infection and intra-operative fracture risk with computer assisted knee arthroplasty is well documented. This study compares the accuracy and cost-effectiveness of the pre- operative MRI based Signature custom made guides (Biomet) to intra-operative computer navigation (BrainLab Knee Unlimited).
Twenty patients from a single surgeon's orthopaedic waiting list awaiting primary knee arthroplasty were identified. Patients were contacted and consented for the study and their suitability for MRI examination assessed. An MRI scan of the hip, knee and ankle was performed of the operative side following a set scanning protocol. Following MRI, patient specific femoral and tibial positioning cutting guides were manufactured. Patients then underwent arthroplasty and intra-operative computer navigation was used to measure the accuracy of the custom made, patient specific cutting guides. A cost analysis of the signature system compared with computer navigation was made.
Our provisional results show that the accuracy of the pre-operative MRI patient specific femoral and tibial positioning guides was comparable to computer navigation.
Pre-operative, patient specific implant positioning cutting guides were as accurate as computer navigation from analysis of our preliminary results. The potential advantages of the MRI based system are accurate pre-operative planning, reduced operating times and avoidance of pin site sepsis. However, further larger studies are required to examine this technique.
