2種類のTKA術中イメージフリーナビゲーションにおける足関節中心認識の差

抄録

Objective: Accurate and precise bone incision and implantation are important for good clinical results in total knee arthroplasty (TKA). However, it is said that approximately 10-20% of malalignments occurs with conventional devices. Navigation is one of the tool to prevent malalignment. We estimated the accuracy of locating the calculated center of the ankle in two different navigation systems (precisioN and iASSIST^TM) in this study.

Methods: Thirty patients who received TKAs in our hospital were included in this study. Preoperative computed tomography data were used to characterize the shape of each tibia and to establish the true centre of each ankle. The virtual center of each ankle was set as the midpoint of the bilateral malleoli in iASSIST^TM, while it was set at 44% of spots from the medial malleoli in precisioN, respectively.

Results: Compared with the true ankle center, the ankle center of precisioN was present 1.9 mm medial, 2.7 mm posterior, and 3.2 mm distal, whereas the ankle center of iASSIST^TM was present 1.6 mm lateral, 3.5 mm posterior, and 3.2 mm distal without skin thickness, respectively. Also, the ankle center of precisioN was present 2.4 mm medial, 2.7 mm posterior, and 3.4 mm distal, whereas the ankle center of iASSIST^TM was present 1.7 mm lateral, 3.6 mm posterior, and 3.9 mm distal with skin thickness, respectively.

Conclusion: In this study, the error of recognizing the centre of the ankle was less than 1 degree in two different image-free navigation systems. If adequate reference points can be digitized, the application of different navigation systems can be utilized with accuracy intraoperatively.