The Design And Application Of Custom-made Artificial Double-action Semi-knee Prosthesis

Knee jiont is not only a vital organs to maintain the standing, weight-bearing, walking and other basic living requirements ,but also is a usual site which is happened the malignant bone tumors. With the support of gradual improvement treatments of Chemotherapy and Radiotherapy in the current, the survival time of patients is prolonged significantly, so artificial prosthetic knee replacement surgery has become the main method of a reconstruction of malignant bone tumors around the limb.The limb salvage treatment of children's patients with malignant bone tumors is a problems in the treatment of of bone tumors. Children's patients whose long segmental bone defects around the knee, as the epiphysis has not been completely closed, can be used a limb prosthesis implantation which could play the role of physical balance in a short term.But, if the patient has a long-term survival, his limb will be shortening>3cm, the patient who has a noticeable limp need to extend the limbs through the reoperation.The malignant bone tumors which is located in metaphyseal and epiphyseal side, because the articular cartilage is a barrier of tumor invasion, therefore we can retain the articular cartilage of the relative bone surface,when excluded from the intra-articular tumor pollution.We can take semi-joint replacement as a treatment for children patients whose knee joints with malignant bone tumors have issues of both lower un equal-length after surgical.. In the previous study,research group use modern computer and engineering knowledge to raise a customiz-made artificial semi-knee prosthesis composite bone limb salvage program to treat the malignant bone tumors childhood knee which is a durable and economical small painful trauma treatment.But, through a long-term animal experiments in the previous study shows after a simple semi-knee replacement, the metal prosthesis will wear and tear with varying degrees on the tibial articular cartilage: less contact part with two-condylar with light wear and tear, more contact part with the two-condylar wear severity - - appear bone defects, wear empty hole.This study which raised a new double-action custom-made semi-knee prosthesis based on a computer-aided design-based (CAD) and Rapid Prototyping (RP) to solved the wear problem of semi-knee prosthesis femoral condyle on the tibial plateau.Study from the design principles of Bipolar artificial femoral head, we designed the structure of double-action in the custom-made semi-knee prosthesis femoral condyle ;The double-action of internal structure can reduce the friction frequency between prosthesis and articular cartilage of the opposite side so as to minimize their wear and tear.The research group has set up the project of custom-made semi-knee joint by"CT/RP/QC"; in the previous study use "Mimics & ImageManager / Surfacer / UG" core technology for the design of programs, pre-data processing result from the loss of surface data; therefore, learn from their predecessors group of three-dimensional reconstruction of mandibular experience, to build and explore "Mimics / Geomagic / Pro-E" at the core of double-action semi-custom knee prosthesis design ---- deal the processing data fast, to complete the joint surface reconstruction of high-quality and physical design.With vitro knee jiont as the subject in vitro experiments, use the dynamic X-ray to observate the knee was sets of before implantation of prosthesis implanted ,double-action semi-knee prosthesis and total knee prostheses in vitro of three respectively, study III group of subjects in the femur when the knee flexion, the lateral condyle of the tibia and femur of the lower end of range of motion of tibial rotation relative to study the double-action semi-knee prosthesis prosthesis in reducing friction with the tibia at the same time the frequency of their movement patterns than total knee replacementDuring the vitro experiments the prosthesis existenced the problem of stability, so research team learn from the tendon fixation device in the privious study, based on the design of customized double-action semi-knee joint prosthesis preliminary, discussed the reconstruction cruciate ligament on the prosthesis ,in order to resolve the stability of semi-knee prosthesis.At present, both at home and abroad there is no coverages about the concept of custom-made double-action semi-knee, also have no research basis of predecessors can be learn from.This study raised the design of custom-made double-action artificial semi-knee prosthesis inorder to solve the wear problem of the custom-made semi-knee prosthesis. This study aim to fill gaps in this field both at home and abroad ,which has important practical significance for the limb salvage therapy of children with malignant bone tumor.