A Study for The Conformity Between Polyethylene Liner and Metal Backing Cup in THR

Ryu, Jei Cheong; Kim, Gyoo Suk; Cho, Hyun Suk; Mun, Mu Seong; Yoo, Myung Chul; Cho, Yoon Je

Abstract

Wear of polyethylene liner and osteolysis appear to be topical problems after long-term follow-up in total hip arthroplasty(THA). Age and activity of patients, manufacturing procedure of polyethylene liner, thickness of the liner, position of acetabular cup, and material of artificial femoral head have of effects on the degree of wear. In addition, conformity, congruency and micromotion between liner and metal cup are likely to be related to the wear. The purpose of this study is 1) to determine the stress caused by contact between metal and polyethylene components, 2) to evaluate the effects of conformity, congruency, and fixation between metal and polyethylene components, on contact stress in acetabular cups and 3) to identify the design parameters of the commercial acetabular cup within the constraints imposed by the overall functional requirements of total joint replacement. The specimens applied to six different commercial cups made in five companies. The methods was performed on dynamic test and static test to rely on load conditions, estimated the gap between the components through LM. The results showed H-G II cup had the most excellent congruency because of the narrowest interval between two components.