title: Development of a non-invasive diagnostic technique for acetabular component loosening in total hip replacements.
abstract: Current techniques for diagnosing early loosening of a total hip replacement (THR) are ineffective, especially for the acetabular component. Accordingly, new, accurate, and quantifiable methods are required. The aim of this study was to investigate the viability of vibrational analysis for accurately detecting acetabular component loosening. A simplified acetabular model was constructed using a Sawbones(®) foam block. By placing a thin silicone layer between the acetabular component and the Sawbones block, 2- and 4-mm soft tissue membranes were simulated representing different loosening scenarios. A constant amplitude sinusoidal excitation with a sweep range of 100-1500 Hz was used. Output vibration from the model was measured using an accelerometer and an ultrasound probe. Loosening was determined from output signal features such as the number and relative strength of observed harmonic frequencies. Both measurement methods were sufficient to measure the output vibration. Vibrational analysis reliably detected loosening corresponding to both 2 and 4 mm tissue membranes at driving frequencies between 100 and 1000 Hz (p < 0.01) using the accelerometer. In contrast, ultrasound detected 2-mm loosening at a frequency range of 850-1050 Hz (p < 0.01) and 4-mm loosening at 500-950 Hz (p < 0.01).
authors.affiliation: The Centre for Orthopaedic Biomechanics, Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, United Kingdom. Electronic address: A.Alshuhri@bath.ac.uk.
authors.forename: Abdullah A
authors.initials: AA
authors.lastname: Alshuhri
authors.affiliation: The Centre for Orthopaedic Biomechanics, Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, United Kingdom. Electronic address: T.P.Holsgrove@bath.ac.uk.
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Holsgrove
authors.affiliation: The Centre for Orthopaedic Biomechanics, Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, United Kingdom. Electronic address: A.W.Miles@bath.ac.uk.
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Miles
authors.affiliation: The Centre for Orthopaedic Biomechanics, Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, United Kingdom. Electronic address: J.L.Cunningham@bath.ac.uk.
authors.forename: James L
authors.initials: JL
authors.lastname: Cunningham
mesh_terms: D061725:Accelerometry / Q000379:methods*; D019644:Arthroplasty, Replacement, Hip; D019544:Equipment Failure Analysis / Q000379:methods*; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008954:Models, Biological; D011475:Prosthesis Failure; D013057:Spectrum Analysis; D014463:Ultrasonography; D014732:Vibration
keywords: Accelerometer; Acetabular cup loosening; Loosening diagnostic; Total hip replacement (THR); Ultrasound; Vibrational technique