Paper—Finite Element Analysis of Contact Stress Distribution on Insert Conformity Design of Total… Finite Element Analysis of Contact Stress Distribution on Insert Conformity Design of Total Knee Arthroplasty https://doi.org/10.3991/ijoe.v18i05.29355 Techin Seechaipat, Supakit Rooppakhun () , Chotchuang Phombut Suranaree University of Technology, Nakhon Ratchasima, Thailand supakit@sut.ac.th Abstract—The tibial insert conformity is one of the essential parameters con- cerned with the contact stress distribution of biomechanics characteristics in total knee arthroplasty (TKA). This study aimed to evaluate the effect of tibial insert conformity design on contact stress distribution using Finite Element (FE) anal- ysis. The three-dimensional (3D) FE model of the posterior stabilized type of TKA was analyzed according to the standard knee implant loading. The 3 k fac- torial experimental design was performed for the response surface of different insert curvatures consisting of the curve, partial flat, and flat insert conformity in sagittal and coronal planes. According to the result, the coronal and sagittal plane conformity displayed the effect of the change on the contact stress, including the contact area for the flexion angle of the knee joint. The maximum contact stress increased while the contact area value decreased during the flexion angle of the knee joints raised. The changing insert conformity value in the sagittal plane dis- played higher sensitivity to contact stress than the changing conformity in the coronal plane. The relationship between the contact stress and tibial insert con- formity under knee flexion angle indicates highly regression suitable for the pre- diction. In addition, the FE simulation result was then verified by compared to mechanical testing using the Fujifilm technique. The result of FE analysis exhib- ited similar to that of the mechanical test. The study indicated that the different geometric designs of the insert conformity played a crucial role that influenced and relationship to the contact stress of TKA. Keywords—insert conformity, total knee arthroplasty, contact stress, finite ele- ment analysis 1 Introduction Total knee arthroplasty (TKA) is an orthopedic surgical procedure widely used to treat osteoarthritis to relieve pain by repairing the weight-bearing surfaces of the knee joint. However, there are still reports of complications from patients after surgery due to problems, such as implant loosening, pain, and weight-bearing surface wear [1]-[3]. The surface wear of the insert component is an essential factor for the shortening life- time included the loosening of TKA [4]-[7]. In extreme situations, revision surgery may be required because of material damage, which generally uses Ultra-High Molecular Weight Polyethylene (UHMWPE) material. Previous studies have found that the wear 96 http://www.i-joe.org