Research On Biomechanical Responses Of The Human Lower After Tumor Artificial Knee Replacement

Osteosarcoma is a malignant tumor originated in the bone tissue, occured around the most complex knee joint which has an important biomechanical function, especially the distal femur. About the treatment of the malignant bone tumors, prosthetic replacement recognized by domestic and foreign medical experts in limb salvage reconstruction. But the perforation injury of anterior femoral cortical bone make a great impact to the knee function after the artificial prosthesis, but few studies analyze the problem. Therefore, the biomechanical response analysis of the femur-prosthesis-tibia complex has important significance after the knee arthroplasty of tumor type.The study bases on the lower limbs CT scan data of a distal femur osteosarcoma line tumor resection patient after tumor total knee replacement and corresponding tumor type knee prosthesis building the patient’s femur prosthesis-tibia finite element model, and using reverse engineering software for further relaxation and smoothing to make the finite element model closer to the actual state, and validated regarding its availability. Secondly, there is a medical biomaterials bone cement with self-curing properties filled in between the femur and prosthesis marrow needle in the proposed model. The paper selects polymethylmethacrylate bone cement used in hospitals commonly for compression test, and obtaining the corresponding bone cement material parameters by experiments which used in further research and analysis.Finally, to study biomechanical responses of the femur-prosthesis-tibia complex in the normal standing state and loading gait knee flexion state after hinged knee arthroplasty of tumor type, and analyze the stress distribution and stress shielding phenomenon of the complex. To investigate occurring reasons of postoperative femoral perforation of patients, so as to provide a theoretical basis for optimal design and manufacture of hinged artificial knee prosthesis of tumor type. During standing gesture, the femur stress is significantly larger than the tibia and presents evident concentration phenomenon. The proximal 1/3 of femoral shaft presents larger stress and shows stress shielding effect. Simultaneously comparing the bone cement filled or no, analysis of the femur stress concentration is more obvious in the absence of bone cement filling situation. In the course of gait,consider the impact of muscle and reverse gait loading conditions, and in knee flexion state, analysis the femoral stress distribution of flexion state in three different angle. Since the model is based on the geometry and bone characteristics of a clinical patient, the stress distribution diagram shows that the location of femur stress concentration is close to the location of patient femur perforation. It indicates that the consistent femur injury behavior comparing with the clinic patient could occur under its own gravity.The contents of this paper for avoiding patients bone injury phenomenon after the artificial prosthesis has practical significance, and at the same for tumor type knee prosthesis design has some reference, with great engineering significance.