Abstract
Aim
To assess the accuracy of predicted and actual cut alignment from PMCB versus intra-operative computer navigation.
Method
We performed 10 primary TKA cases in which both PMCB and computer navigation were used. Standard imaging was performed to generate the plan and the cutting blocks to perform the case with PMCB. At the start of the case, standard navigation procedure was followed using the Praxim navigation system to register the centre of the femoral head, femoral and tibial surfaces and alignment. The PMCB were applied to the femur and tibia and the navigation cut-registering shim was placed in the slot on the PMCB to record the position and alignment of the proposed cut in the coronal and sagittal planes. The following parameters were compared: overall limb alignment in the coronal plane, distal femoral coronal angle, depth of resection on medial and lateral distal femoral condyle and depth of resection on medial and lateral proximal tibia. Differences in the pre-operative PMCB plan, intra-operative navigation assessment and proposed cuts after application of the blocks intra-operatively were recorded.
Results
In no cases did any of the measurements vary by more than 1 degree or 1 millimetre. Correlation co-efficients for all the compared measurements were > 0.95.
Conclusion
The pre-operative plan predicted the alignment and depths of cut with a high degree of accuracy when compared with computer navigation. Once fitted to the bones, the cuts proposed by the patient matched blocks showed excellent correlation with the navigation and the pre-operative plan.
MULTIPLE DISCLOSURES
