Bond strength analysis of the bone cement- stem interface of hip arthroplasties.
OBJECTIVE
To study and establish the preliminary linear and modified models for the interface shear mechanics performance between implant and bone cement and to explore its damage significance.


METHODS
The loosening research between artificial hip joint prosthesis stem and bone cement interface performance can be evaluated by the push-in test. Based on the debonding performance test, the analytical expressions of the average load and displacement from the debonding failure and splitting failure process were deduced and determined. The correlations of the expressions of the average load-displacement and statistical experimental data were analyzed.


RESULTS
It demonstrated that the interface debonding failure mechanical model could be characterized as interface bond strength mechanical performance. Based on analysis of models and experimental data by the three statistical analysis methods, the results indicated the modified model could be better represented by the interfacial debonding strength properties. The bond stress τ and relative sliding s distribution along the embedment regional were coupling affected by both pressure arch effect and shear lag effect in bone cement. Two stress peaks of implant have been found at the distance from 0.175La loading tip to 0.325La free tip, which also verified the early loosening clinical reports for the proximal and latter region. As the bone cement arch effect, the bond stress peak tend to move to the free tip when the debonding failure would be changed into the splitting failure, which presents a preliminary study on the mechanism of early debonding failure for the stem-cement interface.


CONCLUSIONS
Functional models of the stem-bone cement interfacial debonding failure are developed to analyze the relevant mechanism. The different locational titanium alloy stress, and the interfacial bond stress and the relative slides are evaluated to acquire a guide of the different positions of interfacial damage. The coupling effect which is original from the pressure arch and the interfacial shear hysteresis cumulative effect has influence on the interfacial debonding and damage process.
Institute of Tribology and Reliability Engineering, School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China. Electronic address: zhanglf@cumt.edu.cn.
Lan-Feng
LF
Zhang
Institute of Tribology and Reliability Engineering, School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Shi-Rong
SR
Ge
Institute of Tribology and Reliability Engineering, School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Hong-Tao
HT
Liu
Department of Surgery, the Second Xu-zhou Hospital, Xuzhou Medical University, Xuzhou, Jiangsu 221000, China.
Kai-Jin
KJ
Guo
Institute of Tribology and Reliability Engineering, School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Shu-Yang
SY
Han
Institute of Tribology and Reliability Engineering, School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Juan-Yan
JY
Qi
D001843:Bone Cements / Q000737:chemistry*; D006622:Hip Prosthesis; D008422:Materials Testing; D015233:Models, Statistical; D033081:Shear Strength; D014025:Titanium / Q000737:chemistry*
D001843:Bone Cements; D014025:Titanium
Bone cement mantle; Stem-cement debonding; Titanium; Total hip arthroplasty