Design and evaluation of a new short stemmed hip implant using porous titanium material to diminish stress shielding

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Standard treatment of hip arthritis is Total Hip Arthroplasty (THA). Although THA is a successful surgical intervention, failures in younger patients have led to search for alternative solutions which may be more durable and may conserve femoral bone stock for future revision. The increasing popularity of minimally invasive surgery had led to the development of conservative implants. Short stem has the advantage of preserving femoral bone stock for future revision. It is well known that the implantation of a metallic device inside the femur modifies the load transfer to the surrounding bone. Shorter femoral stem may load the femoral bone in a more physiological way and so reduce the risk of stress shielding. This phenomenon, caused by the difference in rigidity between the metal and the bone, leads to bone resorption or decrease of bone density. With the advancement of rapid manufacturing processes, complex structural materials can now be designed such as porous microstructures. Porous metallic materials promote bone cells to grow inside the structure, leading to better osseointegration, consequently better fixation of the implant to the surrounding bone. The aim of this research project is to design and evaluate a short stemmed hip implant made of a new biomimetic material to improve long-term survivorship of the arthroplasty, using biomechanical modeling and finite element analysis. The project foresees two parts. Part 1 consists in evaluating a new short stem implant by investigating the effect of stem length on primary stability and the femoral stresses. Part 2 consists in optimizing the microstructure of the porous titanium material to obtain mechanical properties similar to femoral cancellous bone properties, and investigate bone stress distribution and stress shielding of the short stemmed implant proposed with this material. The proposed program will be based on the previous modeling works of the candidate's group.