The acoustic emission technique in orthopaedics - a review

Abstract

Traditionally, orthopaedic research has focused upon the assessment of individual components in an implanted construct. A great deal of research has investigated the durability of the metallic stem, even though this is the most robust component in the implanted system. Standards have been developed for the structural assessment of the implant and even the bone cement which holds the implant in place in the bone. However, the construct as a whole, and its short-and long-term structural integrity, are rarely assessed, and few methods have been established to monitor and predict the mechanisms leading to failure. These are necessary to ensure that any new implants entering the market will perform satisfactorily and prevent premature revision surgery.The acoustic emission (AE) technique offers the capability of monitoring structural degradation passively and in real time, and can distinguish failure mechanisms and their location through the analysis of AE parameters. In the present paper, the use of acoustic emission in orthopaedics, in particular for the evaluation of hip replacement constructs, is reviewed. Following this, three case studies undertaken at the University of Southampton are presented, in which acoustic emission on-line monitoring has been used to evaluate the performance of simulated artificial hip replacement constructs and their constituents during static and fatigue testing. In Case Study 1, the fatigue behaviour of bone cement is characterized; in Case Study 2, the residual stresses induced in the construct as a result of bone cement cure are investigated; in Case Study 3, the mechanisms leading to failure of a carbon fibre reinforced plastic hip stem during fatigue testing are characterized.

Rupture of anterior cruciate ligament monitored by acoustic emission

“…[1][2][3] The above studies, among others, have been conducted mostly on engineering materials; however, the usefulness of AE has been demonstrated in certain cases of biological materials like tissues or bones. [4][5][6] AE enhances the understanding of the fracture mechanisms of materials with engineering significance, something crucial for construction and repair purposes. The motive for biological tissues monitoring and specifically the anterior cruciate ligament (ACL) is similar.…”

Acoustic Emission Studies in Hip Arthroplasty – Peak Stress Impact In Vitro Cemented Prosthesis

“…Sir John Charnley revolutionized the field of joint arthroplasty in the 1960s with the development of the total hip replacement. He replaced the diseased hip joint with a steel femoral component and a plastic acetabular socket cup combination, both fixed into the bone using a self-curing acrylic cement, polymethylmethacrylate (PMMA) (Browne et al, 2005). That way, he has restored some of the most problematic joints in the human body.…”

“…The growing importance of different Total Hip Arthroplasty (THA) studies is due to increased life expectancy of the population and its social and clinical relevance. Interdisciplinary THA studies such as: biomechanics (Bergmann et al, 2001;Fonseca et al, 2010;Nabais, 2006;Ramos et al, 2005; Stolk et al, 2006;Teixeira et al, 2008; Vieira, 2004); finite element analysis (Bachtar et al, 2006;Nizam Ahmad et al, 2006;Ridzwan et al, 2006) and acoustic emission monitoring (Browne et al, 2005;Cristofolini et al, 2003;Davies et al, 1996;Franke et al, 2004;Gueiral, 2008;Qi et al, 2005;Qi, 2000;Rowland et al, 2004) have been published. Research has been done to improve the performance of artificial implants, addressing factors such as geometry, materials, cements, and other surgical techniques that directly or indirectly, might influence the performance and success of cemented arthroplasty.…”

“…It's important to have a technical solution capably reliable to indicate the time to have a replacement surgery. In this context the Acoustic Emission (AE) has a major role because it allows to determine and analyze cracks, microcracks and defects which can lead to delamination of cement and/or rupture of the connection implant/bone (Browne et al, 2005). The monitoring of the structural integrity of cement and interfaces (implant and bone) by detection of acoustic emission waves, represents a significant advance in the assessment and inspection of the performance of cemented prosthesis, in relation to usual practice, which is the patient operation for prosthesis inspection.…”

“…So, AE monitoring better allows to understand the orthopaedic construction mechanisms and in focusing other mechanisms that were not detected by conventional ways. According to Browne (Browne et al, 2005), signals of AE allows to study the fatigue behaviour of the cement that holds the implant to the bone in orthopaedic implants. With the fatigue test the mechanisms leading to the failure of an hip prosthesis are characterized.…”