Abstract
Object: We studied the kinematics of cruciate-retaining and -substituting total knee arthroplasty (TKA) using image free knee navigation system intra-operatively.
Methods: 14 PCL-retaining TKAs and 34 PCL-substituting TKAs were selected based on the following criteria: any flexion contracture was under 10 degrees and maximum flexion was over 130 degrees, the distribution of valgus/varus was within +/- 3 degrees and the distribution of axial rotation was within 15 degrees at full extension. Both the valgus/varus and the internal/external rotation variations were evaluated using the Navigation System at intervals of 30 degrees from 10 degrees to over 120 degrees of flexion.
Results: In the varus/valgus motion, both the PCL-retaining group and the PCL-substituting group show the similar curve patterns with a valgus tendency from about 10° to 60° of flexion, and a varus tendency from 60° to about 130° of flexion. But as for the internal/external rotation, the PCL-retaining group and the PCL-substituting group show the different curve patterns. Although the PCL-retaining group kept internal rotation from about 30° to maximum flexion, the PCL-substituting group rotated externally from 60° to 90°, and did not rotate internally nor externally from 90 to about 130° of flexion.
Conclusion: These results indicate that the kinematics functions of the navigation system are helpful and practically accurate to analyze the kinematics of a patient's knee in vivo.
