Abstract—The objective of this study was to identify the biomechanics of commercial total knee arthroplasty in kneeling position by Finite Element Method (FEM). Two commercial total knee arthroplasties were created on a 3D Finite Element model of both knee implants at 0, 30, 60, 90, and 120 degrees of knee implant flexion. To identify the contact area and pressure on polyethylene component of both knee implants by Finite Element Method, the largest contact pressures on polyethylene of LPS-Flex and Genesis II are 2.909 and 3.910 MPa presented at 120 degrees on knee implant flexion. The fewest contact pressures on polyethylene are 0.1596 and 0.6389 MPa presented at 0 degree on knee implant flexion. In the same way, the largest contact area of LPS-Flex and Genesis II are 309.786 and 368.68 mm2 presented at 0 degree on knee implant flexion. The fewest contact area of LPS-Flex and Genesis II are 96.2699 and 129.027 mm2 presented at 120 degrees on knee implant flexion. The Finite Element Analysis (FEA) was an effective method to identify contact pressures and contact areas of 3D Finite Element model of both knee prostheses.