The Controlled Study Of The Coverage Rate At Which The Proximal Tibial Plateal Is Covered By The Symmetric And Asymmetric Tibial Prothesis

Objective:To explore the difference of coverage rate at which the resected proximal tibia and anteomedial quadrant of it are covered by a symmetric prothesis and a asymmetric one in the course of total knee arthroplasty.Matherials and methods :We select 30 tibial plateau specimens in the trial,of them,20 specimens are the resected tibial plateau ones from total knee arthroplasties in our operating room, 10 specimens are dry cadaver tibial plateau ones.Three kinds of tibial prothesis are compared .Of them ,Genesis II tibial prothesis is asymmetric ,I-B II ,PFC tibial prothesis are symmetric.The tibial plateau is resected by extramedullary guide,all the resection specimens have a measured thickness of 6-10mm,the resection surface posteriorly slope by 6?.For each tibial specimen,we select one tibial prothesis respectively that can covered tibial plateau by the highest rate from three kinds of prothesis.The tibial specimen and the related prothesis are photographed digitally by the same gratifying rate.The digital photoes are sent to computer,the rate at which the tibial specimen is covered by the tibial prothesis iscalculated.Exact templates of tibial section and tray basplates are produced with transparency plastic sheet. The anteomedial quadrants are landmarked with black pencil on the templates of resections and tray basplates, the digital photoes are taken .The digital photoes are sent to computer,the coverage rate at which the anteomedial quadrant of the tibial section is covered by the anteomedial quadrant of the tibial tray.With the paired-t test method, test the difference of coverage rate at which the resected proximal tibia and anteomedial quadrant of it are covered by a symmetric prothesis and a asymmetric one in the course of total knee arthroplasty.Resultrby the analysis of computer ,the average coverage rate of Genesis II tray to the resected specimens is 88.41 + 1.94%; that of PFC tray is 83.21+ 3.28%;that of I-B IItray is 79.81?.86% .By paired -t test ,the coverage rate of Genesis II tray to the resected specimens is compared to that of PFC tray(P<0.001).The coverage rate of Genesis II tray to that of I-B IItray(P<0.05).The coverage rate of Genesis II tray to the anteomedial quadrant of resected specimens is 82.09+11.42%, that of PFC tray to the anteomedial quadrant of resected specimens is 80.81 + 8.23%, that of I-B II tray to anteomedial quadrant of resected specimens is 75.04?3.66%. Bypaired -t test ,the coverage rate of Genesis II tray to the anteomedial quadrant resected specimens is compared to that of PFC tray(P<0.001).The coverage rate of Genesis II tray to that of I-B II tray(P<0.05).Conclusion: the coverage rate at which the resected proximal tibia and anteomedial quadrant of it are covered by a asymmetric prothesis is much higher than that of a symmetric prothesis.