The Analysis of Polyethylene Hip Joint Endoprostheses Strength Parameters Changes after Use inside the Human Body.

Katarzyna Mordal,Piotr Paszta,Arkadiusz Szarek,Bożena Gzik-Zroska,Dariusz Rydz,Aleksandra Kalwik,Małgorzata Łągiewka,Kamil Joszko,Tomasz Stachowiak,Marek Gzik,Joanna Redutko,Justyna Łukomska-Szarek,Przemysław Postawa

doi:10.3390/ma14227091

Abstract

The influence of dynamic loads resulting from human motor activity and electrocorrosion inside the human body on the strength parameters of artificial joint elements has not yet been investigated. Hip joint arthroplasty is the most common surgical procedure in the world that allows doctors to remove pain and restore motor skills in people with severe hip diseases, after accidents, and in the elderly. Based on the reports, this article assesses changes in the number of implanted endoprostheses in the years 2005–2019 and determines the trends and estimated changes in the number of implanted hip prostheses in the following decades. The study assesses changes in selected strength parameters of UHMW-PE polyethylene inserts of hip joint endoprostheses during their use in the human body. The research was carried out on appropriately collected samples from UHMW-PE cups removed from the human body with a known history and lifetime from 4 to 10 years. Patients’ body weight ranged from 735 [N] to 820 [N], and the declared physical activity was similar in the entire research group. As part of the research, the values of changes in dynamic modules and the mechanical loss coefficient were determined in relation to the share of the crystalline and amorphous phases of artificial UHMW-PE cups, removed from the human body after different periods of exploitation under similar operating conditions. The analysis of selected strength parameters was performed at a temperature of 40 °C, which corresponds to the working conditions inside the human body. On the basis of numerical studies, the influence of changes in material parameters on the deformation of the artificial acetabulum during the patient’s motor activity, which is one of the causes of fatigue destruction, was determined.

Highlights

Bone and joint dysfunctions are the primary cause of social and work absence of people all over the world
The period and intensity of using polyethylene cups inside the human body affects the changes in the strength parameters of UHMW-PE
Two load variants were analysed for the extreme values of the body weight of patients who underwent reimplantation of the damaged artificial joint, i.e., BW1 = 735 [N] oraz BW2 = 820 [N]

Summary

Introduction

Bone and joint dysfunctions are the primary cause of social and work absence of people all over the world. Joint arthroplasty is an expensive procedure, depending on the area of operation, age and weight of the patient, the extent of the procedure, type of prosthesis and components used, in most cases it is the only way to effectively and completely cure disability in millions of people around the world [3,4,5]. Despite the dynamic development in the field of materials engineering, it was not possible to develop an artificial friction node that would be universal and sufficiently failure-free to be implanted in all patients. Research is constantly being carried out on the introduction of modern materials for the components of artificial joints and the improvement of the lifetime of endoprostheses, with particular emphasis on the friction node [6,7]. The second main current of engineering research is the analysis of the state of stresses and strains in the elements of artificial joints and their impact on tissues [8,9]

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