Assessing the accuracy of bone cuts in total knee arthroplasty using custom patient specific cutting blocks

Patient Matched Instrumentation(PMI) in Total Knee Arthroplasty (TKA). All patients will undergo routine pre-operative assessment as well as an Magnetic Resonance Image (MRI) scan & long leg x-rays which are used to make “Visionaire” patient matched disposable cutting blocks (instruments). The cutting blocks are made from pure ‘nylon 12’ material, and are made as a single use disposable item designed to match perfectly the patients anatomy. At the time of surgery, patients will undergo routine preparation for navigation with computer assisted surgery (CAS) surgery. Instead of manual placement of a standard cutting blocks under navigation, the Visionaire cutting blocks will then be applied and fixed with standard pins. The position of the blocks will then be referenced to the patients anatomy registered on the CAS, and the data recorded. If the position is inadequate, the blocks will be replaced with standard CAS instruments and the surgery proceed as normal. The surgery will take approximately 90 minutes. All patients will be assessed post-operatively with standard radiographs including long leg films to assess alignment and verify component position. These will be done by 12 weeks post-op.