Restoration of the Mechanical Axis in Total Knee Artrhoplasty Using Patient-Matched Technology Cutting Blocks. A Retrospective Study of 132 Cases

Background: The aim of this study is to evaluate the accuracy of bone cuts and the resultant alignment, using theMyKnee patient specific cutting blocks.Methods: We retrospectively reviewed 132 patients undergoing primary TKR for osteoarthritis by one single surgeon.The operative time, the preoperative Hip-Knee-Ankle (HKA) axis based on the CT-scan, the postoperative HKA axisbased on long axis standing x-rays, the planned and the actual size of the femoral and the tibial components, and thenumber of the recuts which has been made intraoperative were measured.Results: The average preoperative HKA axis was 177.50 (range 163.50 to 1940), whereas the average postoperativeHKA axis was 179.40 (range 177.10 to 182.70). No outliers were reported in the study (0%). Intraoperatively, 4 femoralcomponents (3.03%), and 7 tibial components (5.30%) applied to the patients were different than the planned size.There was no need of recuts in any of our cases intraoperatively.Conclusion: The MyKnee system evaluated in this study was shown to be remarkable reliable in the coronal planealignment, and the prediction of the component size. However, further studies are needed to determine whether thereare any clinically important improvements in outcomes or patient satisfaction when using patient-specific cutting blocksfor TKA.

Keywords:

CT Scan , HKA ankle , Knee alignment , Patient specific instruments , Total knee arthroplasty