Papers by Keyword: THR

Abstract: Orthopedic cement is an essential component of cemented Total Hip Replacements (THR). It must ensure three essential functions: very good implant-cement adhesion, good bone-implant load transfer, and good antibiotic transport. The main objective of the present work is to study the fracture behavior of orthopedic cement in total hip replacements. The analysis is performed using the submodel technique. Two cases are being considered. The first case involves ordinary cracks, while the second case involves cracks emanating from cavities in the cement of the THR acetabular part. The effects of crack position and implant orientation on the variation of stress intensity factors (SIF) in the three failure modes are discussed. It has also been shown that the circumferential positions of cracks present a major risk of loosening of the prosthesis, especially when the defect is aligned with its axis.

Abstract: The UHMWPE acetabular cups are the most popular joints for joint prostheses after Charnley introduced UHMWPE for the acetabular component in 1962. It has been demonstrated that polyethylene wear remains the main source of particles in the THR and therefore requires particular attention. The paper presents a series of theoretical and practical aspects regarding the wear of acetabular cups (made of UHMWPE) from the total hip prosthesis component. At the same time, the other tribological phenomena that occur in these MoP (metal on polyethylene) combinations are treated, such as lubrication and friction. Total Hip Replacement & Hip Resurfacing A hip replacement involves replacing the hip joint with a mechanical bearing system which is comprised of a femoral component and an acetabular component. During a hip replacement the acetabulum is reamed and the acetabular component is fitted into the cavity and the femoral component can either be placed over a reamed femoral head, in a procedure referred to as hip resurfacing, or positioned inside the femoral shaft during a total hip replacement [1]. Fig. 1. Total Hip Replacement (a) and Hip Resurfacing Replacement (b) [2].