الفهرس 
SummaryOnly 14 pages are availabe for public view
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Abstract
Patients with diseased or damaged hip joints need to undergo a total or partial hip arthroplasty to improve their quality of life.Traditionally, hip implants are comprised of dense solid components manufactured of heavy biocompatible alloys. Once implanted in the femur bone, traditional implants cause a transformation in the natural load distribution through the human bone. Since bones consist of an adaptive living tissue, they modify their regeneration model according to the new load distribution. The new regeneration model develops a problem known as stress shielding in which bones are no longer properly loaded, so they adapt themselves to a lower growth rate. This phenomenon causes the bone to gradually resorb around the implant leading finally to an implant failure due to bone resorption. One of the main components of the mechanical hip joint is the hip stem that is fixed inside the femur bone canal. The hip stem can be fixed with or without using bone cement. In this research, the design of cementless hip stems is improved based on two trends. First, the hip stem solid design is replaced by another porous design. The new porous design is engineered so that the stem starts with a solid neck section where the applied stresses are highest.The solid neck is followed by a porous section in the middle to promote bone ingrowth. Lastly, the end of the stem is designed as a hollow shell since it is functioning under low-stress values. The proposed design provides drug delivery channels which are suitable for injecting antibiotics, growth factors, or even biodegradable cement. Samples of the proposed porous design were manufactured of Ti6Al4V using electron beam melting additive manufacturing approach. These samples were experimentally tested under compression and flexural loading scenarios. The full stem design was tested using finite element analysis and proved capable of withstanding the applied loads while improving the load distribution within the femur bone. The second development trend is incorporating new biocompatible alloys for the implant. Second-generation titanium alloys have mechanical properties that are closer to the properties of natural human bone when compared to the traditional materials. Additionally, these alloys were presented to prevent the adverse tissue reactions related to aluminum and vanadium elements of the famous Ti6Al4V alloy. A finite element model was developed to study the influence of using second generation titanium alloys on the distribution of stresses and strains through the femur bone.