The PhD thesis by Assistant Professor Saif Mohamed Abbas at the Department of Prosthetics and Orthotics Engineering was defended on Sunday, February 23, 2025. The thesis focused on "Osseointegrated Prosthetics," a surgical implant that is inserted into the remaining bone of different amputation levels, where the bone implant is connected to the external prosthetic limb, enhancing comfort, mobility, and the quality of life for patients.

The study explored the mechanical, chemical, and microstructural properties of the Ti-13Nb-13Zr alloy as an osseointegrated prosthetic implant. The results showed good corrosion resistance, bacterial resistance, and acceptable adhesion strength. Live rabbit tests were also conducted to measure the removal torque two weeks and six weeks post-implantation. The results showed a significant improvement in torque for the samples coated with Hydroxyapatite (HAp) by 50%. Furthermore, histopathological tests confirmed that HAp-coated screws showed better osseointegration and less inflammation compared to uncoated screws, with significant bone formation observed after 6 weeks.

The study also involved the design, manufacturing, and analysis of an advanced prosthetic foot, specially tailored for amputees with osseointegrated implants. Additionally, it included the design of a hip joint and four types of connectors (slanted and sliding) to improve alignment, balance, and walking for the amputee, with numerical analysis performed as well.

The numerical simulations using ANSYS for the osseointegrated implant with leg and thigh bones at various amputation levels demonstrated successful safety factors in all cases. The implant designs for three patients (below-knee, above-knee, and hip-level amputations) showed favorable results when compared to yield stress, which was lower than the stress on the implant material, bone, and foot. These findings suggest the potential application of Ti-13Nb-13Zr alloy in osseointegrated prosthetics, opening new avenues for enhancing prosthetic design and its use in biomedical engineering.