Design and manufacture of knee prosthesis wear simulator

Nowadays, knee joint prostheses are used extensively in surgical operations as a result of traffic accidents and sports injuries, especially the cartilage structure that occurs in the knee joints of individuals. However, the life span of the used knee prosthesis is unknown. For this reason, knee simulators are needed. In this study, the design and manufacture of a knee simulator, which can simulate knee movements in order to observe erroneous conditions in the UHMWPE (ultra high molecular weight polyethylene) component, which is one of the knee joint prosthetic components during use, has been realized. The design was implemented so as to be able to apply the motion variations specified in the ISO 14243 standard. In the study, the parts modeled in the CAD environment were produced on the machining machines. After completing the assembly phase of the produced parts, control works were carried out with PLC and motor driver cards for the used motors. In the final phase of the work, three different cycle counts were performed, 100x103, 200x103 and 300x103 and microscope images and surface roughness measurements were taken from the sample as a result of the tests. As a result of the study, it was seen that the servomotors provided their positions with a maximum deviation of 1% from the baseline value. Since the linear actuators used are DC motors, the device is operated with the distances determined by limit switchers instead of the standard values. The motor used for axial force was operated at 800 N load and the motor used for anterior / posterior movement was operated at the maximum stroke of 5.2 mm. In addition, it has been observed that the increase of the number of cycles in the taken microscope images causes an increase in surface defects and surface roughness.