The current approach to research and design of the artificial hip prosthesis: a review

One of the most successful techniques in restoration of degenerated joint functions is total hip replacement. This surgical approach includes removal of diseased cartilage and bone parts, and replacement by the corresponding joint prostheses. By using metal alloys, high quality plastic and polymer materials, orthopedic surgeons can reconstruct hip fractures, or replace a painful, dysfunctional joint with highly functional, long-lasting prostheses, enabling hundreds of thousands of people to live a more fulfilling and active life. However, most of these implants only last for 10-15 years, and one of the most common problems for both patients and doctors is implant failure. Observed in long-term, implant loosening is the main cause of failure. Occasionally, dislocation or bending of implants may occur. Fatigue fracture and wear were identified as the main problems related to loosening of implants, stress shielding, and final implant failure. There are several factors which contribute to implant integrity, including material and design, implant positioning, cementing technique and patient characteristics. To improve integrity and life of hip implant by using finite element analysis, two major factor should be considered, design and biomaterial. By using this method there are various parameters that should be define, including complex geometry of the bone and an implant, biomaterial properties, and specifics boundary conditions, i.e. contact between the hip prosthesis and the bone depending on fixation method. In orthopedic biomechanics finite element method was first used for the purpose of determining the stresses in human bones. Since then, this method has been more and more frequently applied in determining of stress state in bones and prostheses, as well as fracture fixation devices, including hip implants. This paper presents a review study of factors influencing design process and structural integrity of the hip implant. Correspondence to: K. Colic, University of Belgrade, Innovation Center, Faculty of Mechanical Engineering, Kraljice Marije 16, 11 000 Belgrade, Serbia, E-mail: [email protected]