Investigation of different loading effects on lower extremity prosthesis

In this study, total ankle prostheses which are used for damaged ankles have been examined. In the first section of the study, the anatomy and biomechanical properties of ankle-foot complex have been described. Then, ankle prostheses which are widely used today and investigation results about these prostheses have been investigated. In the second part of the study the effects of total ankle replacement systems on the behaviors of ankle-foot complex have been investigated numerically and experimentally. At the numerical investigation part of the study, solid models of the normal and prosthetic ankle-foot complex bones, soft tissues and components of prosthesis have been generated by using CT images and MIMICS (Materialise) software and SOLIDWORKS software. Then these models have been transformed into ABAQUS codes. In the FEM models for normal ankle, interactions between bones to cartilages, and soft tissues to ground supports have been considered as sliding contact parts while interactions between the soft tissues and bone surfaces have been defined as tied contacting parts. In addition, for prosthetic ankle between the components of prosthesis and tibia and talus, sliding contacts have been defined. For balanced standing position numerical static analyses of models have been carried out and stress, strain and plantar pressure distribution of the normal and prosthetic ankles have been compared. At the experimental investigation part of the study, force displacement values of a normal and prosthetic cadaver foot for different standing positions have been investigated by using an experimental setup. Finally, obtained numerical and experimental results for normal and prosthetic foot-ankle complex have been compared.