Effect of Physiological Fluids Contamination on Selected Mechanical Properties of Acrylate Bone Cement

Robert Karpiński; Jakub Szabelski; Jacek Maksymiuk

doi:10.3390/ma12233963

Effect of Physiological Fluids Contamination on Selected Mechanical Properties of Acrylate Bone Cement

Materials (Basel). 2019 Nov 29;12(23):3963. doi: 10.3390/ma12233963.

Authors

Robert Karpiński¹, Jakub Szabelski², Jacek Maksymiuk³

Affiliations

¹ Department of Machine Design and Mechatronics, Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland.
² Section of Biomedical Engineering, Department of Computerization and Production Robotization, Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland.
³ Orthopaedic Department, Łęczna Hospital, Krasnystawska 52, 21-010 Łęczna, Poland.

Abstract

This study analyses the degradation rate of selected mechanical properties of bone cement contaminated with human blood and saline solution. During the polymerisation stage, the PMMA cement specimens were supplemented with the selected physiological fluids in a range of concentrations from 0% to 10%. The samples were then subjected to the standardised compression tests, as per ISO 5833: 2002, and hardness tests. The obtained results were analysed statistically to display the difference in the degradation of the material relative to the degree of contamination. Subsequently, numerical modelling was employed to determine the mathematical relationship between the degree of contamination and the material strength degradation rate. The introduction of various concentrations of contaminants into the cement mass resulted in a statistically significant change in their compressive strength. It was shown that the addition of more than 4% of saline and more than 6% of blood (by weight) causes that the specimens exhibit lower strength than the minimum critical value of 70 MPa, specified in the abovementioned International Standard. It was further revealed that the cement hardness characteristics degraded accordingly. The mathematical models showed a very good fit with the results from the experiments: The coefficient of determination R² was 0.987 in the case of the linear hardness model for blood and 0.983 for salt solution; secondly, the values of R² for the third-degree polynomial model of compressive strength were 0.88 for blood and 0.92 for salt. From the results, it can be seen that there is a quantitative/qualitative relationship between the contamination rate and the drop in the tested mechanical characteristics. Therefore, great effort must be taken to minimise the contact of the bone cement with physiological fluids, which naturally occur in the operative field, particularly when the material cures, in order to prevent the cement material strength declining below the minimum threshold specified in the ISO standard.

Keywords: biodegradation; bone cement; compressive strength; contamination; hardness; human blood; mechanical properties; saline solution.

Grants and funding

This research project was financed in the framework of the Lublin University of Technology-Regional Excellence Initiative project, funded by the Polish Ministry of Science and Higher Education (contract no. 030/RID/2018/19)./Lublin University of Technology