Effects of Different Prosthetic Instrumentations on Tibial Bone Resection in Total Knee Arthroplasty

Abstract Objective For total knee arthroplasty (TKA) tibial bone resection, various manufacturers provide cutting blocks with fixed angles. But the accuracy of these angles is uncertain. Our aim was to assess the accuracy of the obtained posterior tibial slope (PTS) with a fixed angle cutting block.Methods 247 TKAs in 213 patients were reviewed. We included 104 Legion Prosthesis, 76 U2 Knee Prosthesis, 46 NexGen LPS-Flex Prosthesis, and 21 Vanguard Knee System products. Preoperative and postoperative PTS were measured via expanded lateral tibia radiographs. The tibial component coronal alignment angle (TCCA) was measured on postoperative standing full-length anteroposterior radiographs, and the tibia length was measured on preoperative standing full-length radiographs. Results For postoperative PTS, the Legion group had significantly smaller slopes than the U2 Knee group and Vanguard group. However, there was no significant difference between the Legion and NexGen groups, and no significant difference among the NexGen, U2 Knee, and Vanguard groups. One sample t-test indicated that only the NexGen group showed no statistical difference from the 7° PTS and 90° TCCA it aimed to provide. Multiple linear regression showed that the different tibial lengths and preoperative PTS had statistically significant effect on postoperative PTS. However, there were weak correlations between the tibial length and PTS, and between preoperative and postoperative PTS.Conclusion For TKA, using conventional tibial bone resection technology with different tibial cutting instrumentations provided by various manufacturers can obtain safe PTS. However, the PTS is not completely consistent with the angle of the cutting block.