In this study, six virtual models of the prosthetic human knee joint are developed and analyzed with the finite element method (FEA). The study is based on the virtual model of the human knee joint, as well as that of an existing knee prosthesis, often used in total knee arthroplasty, virtual models developed and presented in other previous works. Based on FEA, the effects of varus angle and antero-posterior tibial inclination (a-p.t.i) on the stresses developed in the components of the knee prosthesis are studied. Using AnsysWorkbench software, von Mises stress maps and maximum stress values are obtained for the six prosthetic knee assemblies and for each of the three components of the prosthesis: polyethylene insert, tibial component and femoral component. For each case of prosthesis-knee assembly (corresponding to a varus angle of 176o, 182o and 188o, two variants were considered: an a-p.t.i of 00 and 50 respectively. The results show that as the varus angle increases, the von Mises stresses increase in all prosthesis components, and for an a-p.t.i of 5o, the von Mises stresses decrease in all three components of knee prosthesis. The results, confirmed by clinical observations, suggest that the a-p.t.i  of 5 0 is favorable.

Full Text:



Be’ery-Lipperman M, Gefen A., A method of quantification of stress shielding in the proximal femur using hierarchical computational modelin, Computer Methods in Biomechanics and Biomedical Engineering, 9(1), pp. 35–44, 2006.

Papini, M., Zdero, R., et al., The biomechanics of human femurs in axial and torsional loading: comparison of finite element analysis, human cadaveric femurs, and synthetic femurs, J Biomech Eng, 129(1), pp. 12–19, 2007.

Tarnita, D., Popa, D., Tarnita, D.N., Grecu, D., CAD method for 3D model of the tibia bone and study of stresses using the finite element method, Rom J Morphol Embryol, 47(2), pp. 181-186, 2006.

Taddei, F., Cristofolini, L., Martelli, S., Gill, H.S., Viceconti, M., Subject-specific finite element models of long bones: An in vitro evaluation of the overall accuracy, J Biomech, 39(13), pp. 2457–2467, 2006.

Tarnita, D., Tarnita, D.N., Popa D., Grecu, D., Niculescu, D., Numerical simulations of human tibia osteosynthesis using modular plates based on Nitinol staples, Romanian Journal of Morphology and embryology, 51, pp. 145-150, 2010,

Tarnita, D., Catana, M., Dumitru, N., Tarnita, D.N, Design and Simulation of an Orthotic Device for Patients with Osteoarthritis, 38, pp. 61–77, 2016.

Penrose, J.M.T., Development of an accurate three dimensional finite element knee model, Comp. Meth. In Biomech. and Biomed. Eng. 5, pp. 291-300, 2002.

Tarnita, D., Tarnita, D.N., Bolcu, D., Orthopedic implants based on shape memory alloys. In: Fazel-Rezai R (ed). Biomedical Engineering – From Theory to Applications, InTech, Viena, pp. 431-468, 2011.

Donahue, TLH., Hull M., Rashid M., Jacobs C., A finite element model of the human knee joint for the study of tibio-femoral contact, J.Biomech.Eng., pp. 273-280, 2002.

Tarnita, D., Catana, M., Tarnita, D.N., Modeling and Finite Element Analysis of the Human Knee Joint Affected by Osteoarthritis, Key Engineering Materials, pp 147-150, 2014.

Wilson, W., van Donkelaar, C.C., van Rietbergen, B., Huiskes, R., The Role of Computational Models in the Search for the Mechanical Behavior and Damage Mechanisms of Articular Cartilage, Med. Eng. Phys., 27(10), pp. 810-826, 2005.

Kubicek, M., Zdenek, F., Stress strain analysis of knee joint, Engineering Mechanics, 16(5), pp. 315–322, 2009

Tarnita, D., Catana, M., Tarnita, D.N., Contributions on the modeling and simulation of the human knee joint with applications to the robotic structures, In “New Trends on Medical and Service Robotics: Challenges and Solutions”, Mechanisms and Machine Science, 20, Springer Verlag, pp. 283-297, 2014.

Bae, J.Y., Park, K.S., Biomechanical analysis of the effects of medial meniscectomy on degenerative osteoarthritis, Med Biol Eng Comput., 50, pp. 53–60, 2012.

Tarnita, D., Tarnita, D.N., Bizdoaca, N., Popa, D., Contributions on the dynamic simulation of the virtual model of the human knee joint. Materialwissenschaft und Werkstofftechnik, 40(1-2), pp. 73-81, 2009

Yang, N.H., The effect of the frontal plane tibiofemoral angle on the contact stress and strain at the knee joint, Mechanical Engineering Dissertations Department of Mech. and Ind. Engineering, Northeastern University, 2009.

Matsuda, S., Miura, H., Nagamine, R., Urabe K., Ikenoue, T., Okazaki, K., Iwamoto, Y., Posterior tibial slope in the normal and varus knee, Am J Knee Surg, 12(3), pp. 165–168, 1999.

Szivek, J., Anderson, P., Benjamin, J., Average and Peak Contact Stress Distribution Evaluation of Total Knee Arthroplasties, The Journal of Arthroplasty, 11(8), pp. 952-963, 1996.

Vidal, A., Lesso, R., Rodrighez, R., Garcia, S., Daza, L., Analysis, simulation and prediction of contact stresses in articular cartilage of knee joint, WIT Transactions on Biomedicine and Health, 12, pp. 55-64, 2008.

Chantarapanich, N., Nanakorn, P., Chernchujit, B., Sitthiseripratip, K., A finite element study of stress distributions în normal and osteoarthritic knee joints, J Med Assoc Thai, 92 (Suppl 6): S97-103, 2009.

Tarnita, D., Boborelu, C., Popa, D., Rusu, L., The three-dimensional modeling of the complex virtual human elbow joint, Romanian Journal of Morphology and embryology, 51(3), pp 489-495, 2010.

Speirs, A.D., Heller, M.O., Duda, G.N., Taylor, W.R., Physiologically based boundary conditions in finite element modelling, J Biomech, 40(10), pp. 2318–2323, 2007.

Tarnita, D., Tarnita, D.N., Bizdoaca, N.C Tarnita, C. Berceanu, C. Boborelu, Modular adaptive bone plate for humerus bone osteosynthesis, Romanian Journal of Morphology and embryology, 50(3), pp. 447-452, 2009.

Tarnita, D., Berceanu, C., Tarnita, C., The three-dimensional printing – a modern technology used for biomedical prototypes, Materiale plastice, 47(3), pp. 328-334, 2010.

Godest, A.C., de Cloke, C.S., Taylor, M., Gregson, P.J., Keane, A.J., Sathasivan, S., Walker, P.S., A computational model for the prediction of total knee replacement kinematics in the sagittal plane, J Biomech 33(4), pp. 435–442, 2000.

Tarnita, D., Pisla, D., Geonea, I., et al., Static and Dynamic Analysis of Osteoarthritic and Orthotic Human Knee, J Bionic Eng, 16, pp. 514-525, 2019.

Yang R.S., Lin H.J., Contact stress on polyethylene components of a new rotating hinge with a spherical contact surface, Clin Biomech 16(6), pp. 540–546, 2001.

Tarnita, D., Calafeteanu, D., Catana, M., Geonea, I., Tarnita, D.N., Development of a Three-Dimensional Finite Element Knee Prosthesis Model, Applied Mechanics and Materials, 822, pp. 150-155, 2016

Halloran, J.P., Explicit finite element modeling of total knee replacement mechanics. J.Biomech. 38, pp. 323-331, 2004.

Calafeteanu, D., Tarnita, D., Catana, M., and D.N. Tarnita, Influences of Antero-Posterior Tibial Slope on the Prosthetic Knee Contact Stresses, Applied Mechanics and Materials, 823, pp. 137-142, 2016.

Shen, Y., Li, X., Fu, X. et al., A 3D finite element model to investigate prosthetic interface stresses of different posterior tibial slope, Knee Surg Sports Traumatol Arthrosc 23, pp. 3330–3336, 2015.

Calafeteanu, D., Tarnita, D., Tarnita, D.N., Numerical simulations of 3D model of knee-prosthesis assembly with antero-posterior tibial slope, IftoMM Congress, Taiwan, 2015.

Calafeteanu, D., Tarnita, D., et al., Influences of Varus Tilt on the Stresses in Human Prosthetic Knee Joint, Applied Mechanics and Materials, 823, pp. 143-148, 2016.42

Lee, H.Y., Kim, S.J., Kang, K.T., Kim, S.H., Park, K.K., The effect of tibial posterior slope on contact force and ligaments stresses in posterior-stabilized total knee arthroplasty-explicit finite element analysis, Knee Surg Relat Res, 24(2), pp. 91–98, 2012.

Panni, A.S., Cerciello, S., Vasso, M., Tartarone, M., Stiffness în total knee arthroplasty, J Orthop Traumatol, 10(3), pp. 111–118, 2009.

Gherman, B., Birlescu, I., Plitea, N., et al., On the singularity-free workspace of a parallel robot for lower-limb rehabilitation, Proceedings of the Romanian Academy, 20(4), pp. 383-391, 2019.

Dollar, A.M., Herr, H. Lower Extremity Exoskeletons and Active Orthoses, Challenges and State of the Art. IEEE Trans Robot, 24, pp. 144–158, 2008.

Lui, Z. W., Awad, M. I., Abouhossein, A., Dehghani-Sanij, A. A., Messenger, N., Virtual prototyping of a semi-active transfemoral prosthetic leg, Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 229(5), pp. 350–361, 2015.

Savu S. V., Savu I. D., Benga G. C., Ciupitu I., Improving functionality by laser technology surfacing, Optoelectronics and Advanced Materials, Rapid Communications, 10(9-10), 752-760, 2016.

Weiguang, H., Samer, M., Juan, C. M., Yacine, A., Lower limb wearable robots for assistance and rehabilitation: A State of the Art, IEEE Systems Journal, pp. 1- 14, 2014.

Pisla, D., Plitea, N., Gherman, et al., Kinematics and Design of a 5-DOF Parallel Robot Used in Minimally Invasive Surgery, Advances in Robot Kinematics: Motion in Man and Machine, 2, pp. 99-106, 2010.

Vaida, C., Birlescu, I., Pisla, A., et al., Systematic Design of a Parallel Robotic System for Lower Limb Rehabilitation, IEEE Access, 8, pp. 34522-34537, 2020.


  • There are currently no refbacks.