Finite Element Analysis And Testing For The Mechanical Properties Of Tibial Tray In A PEEK Total-joint Prostheses

Objective:The purpose of this study was to preliminarily predict and evaluate PEEK tibial tray for total knee arthroplasty,and to provide theoretical basis for the further biomechanical test of prosthesis.Methods : The flexural modulus and bending strength of PEEK standard sample produced by injection molding following irradiation sterilization were measured by bending test(ISO 527).Tensile modulus,strength at yield and fracture,and elongation at break were measured by tensile test(ISO 178).Results were compared with the ISO standard.Besides,three-dimensional finite element analysis was used to simulate the loading of the PEEK tibial tray,to predict the size of the tibial tray in the fatigue test,and to determine the mechanically worst size of the FEEK tibial tray for further biomechanical testing.Results:Tensile strength at break(?s)is 91.68 ± 0.31 MPa,tensile strength at yield(?b)is 77.16 ± 0.67 MPa,tensile modulus(Et)is 305.27 ± 19.27 MPa and median(quartile)of the elongation at break was 42%(18%),which were all significantly higher than the minimum requirement in ISO 527.Bending modulus(E)is 3135.67 ± 11.41 MPa,bending strength(P)is 142.86 ± 0.63 MPa,which were alos significantly higher than the minimum requirements in ISO 178.The analysis of stress and strain in the finite element analysis using the equivalent stress-strain criterion of the plastic material shows that the stress and strain concentration are consistent in all different sizes,focusing on the load-bearing structure in the tibial tray structure design,where the smallest size 1L in laterally bearing condition had the largest maximum stress values among all sizes.Conclusion:The parameters of the PEEK standard sample,produced by injection molding following irradiated sterilization,can meet the ISO standard in the tensile test and the bending test.The minimum size 1L tibial tray in the existing design is most likely to occur destruction under specific loading,which can be produced as the worst size for subsequent biomechanical evaluation.