Non-destructive and non-invasive observation of friction and wear of human joints and of fracture initiation by acoustic emission

Abstract

Quality control in orthopaedic diagnostics according to DIN EN ISO 9000ff requires methods of non-destructive process control, which do not harm the patient by radiation or by invasive examinations. To obtain an improvement in health economy, quality-controlled and non-destructive measurements have to be introduced into the diagnostics and therapy of human joints and bones. A non-invasive evaluation of the state of wear of human joints and of the cracking tendency of bones is, as of today's point of knowledge, not established. The analysis of acoustic emission signals allows the prediction of bone rupture far below the fracture load. The evaluation of dry and wet bone samples revealed that it is possible to conclude from crack initiation to the bone strength and thus to predict the probability of bone rupture.

Three-point bending and acoustic emission study of adult rat femora after immobilization and free remobilization

“…2) is typical of crack initiation and propagation in bone (Schwalbe et al, 1999;Jonsson and Eriksson, 1984). In our tests AE signals were recorded almost exclusively during the nonlinear deformation similarly to results reported by others (Fischer et al, 1986;Jonsson and Eriksson, 1984;Wright et al, 1981).…”

“…Several attempts have been made to study processes of cortical bone fracture using measurements of acoustic emission (AE) from bone during mechanical testing (Fischer et al, 1986;Jonsson and Eriksson, 1984;Netz et al, 1980;Schwalbe et al, 1999;Wright et al, 1981). AE signals were usually recorded in the nonlinear region of the tests and were attributed to microcracks formation and/or propagation.…”

Fracture monitoring by acoustic emission: recent applications of parameter-based characterization

“…For specimens fractured near the fix point, both sensors registered average value of RT higher than 30 μs, (31.5 μs to 82.5 μs) while for specimens broken at the head the average value was always lower than 30 μs (3.6 μs to 28.4 μs). In a previous study of combined bending and torsion load in femur bones RT has been used to distinguish between nucleation or propagation of cracking and friction of the existing crack sides [21]. In similar fashion the RA value for dominant torsion cracking was between 1745 μs/V and 14544 μs/V, while for bending fracture of the head it varied between 720 μs/V and 2397μs/V exhibiting limited overlap.…”

Biomarkers for knee osteoarthritis: new technologies, new paradigms

“…In recent years there has been increasing interest in translational applications of acoustic science to inform the diagnosis and management of several different health [31][32][33][34][35][36][37][38][39] and dental conditions [40,41]. In this context, the development of techniques to measure highfrequency AE in knee joints [16][17][18][19] offers the potential to develop a biomarker reflecting the integrity of interactions between knee joint components during weightbearing movement.…”