Investigation of the control of rotational alignment in the tibial component during total knee arthroplasty.

BACKGROUND: In this study, rotational errors that occur in relation to the tibial component of total knee arthroplasty (TKA) were investigated intraoperatively using a CT-free navigation system and postoperative CT images to confirm the correctness of the rotation.

METHODS: Forty patients who underwent TKA using the navigation system were examined. These patients were split evenly into two groups, those whose rotational position was confirmed using a mark made manually on the tibia, and those whose rotation was confirmed using the navigation. All patients underwent postoperative CT scanning and were evaluated using the Knee Society Score.

RESULTS: With navigation, a significant difference was found between the rotational positions for which we made a keel hole and those for which the tibial component was inserted unguided. After cementing, the rotational position in the group for which a manual mark was used to confirm the rotation differed significantly from the position for the group for which navigation during cementing was used. Although there were four outliers that had rotational errors over 3° after cementing in the manual mark group, there were no outliers in the navigation group. While there was significant difference in the rotational errors of the tibial component on postoperative CT between two groups, the Knee Society Score did not differ between two groups.

CONCLUSION: The exact rotation of a tibial component cannot be maintained by simply creating a keel hole. The use of a manual mark resulted in rotational errors of the tibial component and the creation of the outliers. Therefore, it is suggested that the use of a navigation system can reduce the occurrence of such errors.