title: Vibroacoustography for the assessment of total hip arthroplasty.
abstract: OBJECTIVE
  This paper proposes imaging with 3-dimensional vibroacoustography for postoperatively assessing the uncovered cup area after total hip arthroplasty as a quantitative criterion to evaluate implant fixation.
  
  
  METHODS
  A phantom with a bone-like structure covered by a tissue-mimicking material was used to simulate a total hip arthroplasty case. Vibroacoustography images of the uncovered cup region were generated using a two-element confocal ultrasound transducer and a hydrophone inside a water tank. Topological correction based on the geometry of the implant was performed to generate a 3-dimensional representation of the vibroacoustography image and to accurately evaluate the surface. The 3-dimensional area obtained by the vibroacoustography approach was compared to the area evaluated by a 3-dimensional motion capture system.
  
  
  RESULTS
  The vibroacoustography technique provided high-resolution, high-contrast, and speckle-free images with less sensitivity to the beam incidence. Using a 3-dimensional-topology correction of the image, we accurately estimated the uncovered area of the implant with a relative error of 8.1% in comparison with the motion capture system measurements.
  
  
  CONCLUSIONS
  Measurement of the cup coverage after total hip arthroplasty has not been well established; however, the covered surface area of the acetabular component is one of the most important prognostic factors. The preliminary results of this study show that vibroacoustography is a 3-dimensional approach that can be used to postoperatively evaluate total hip arthroplasty. The favorable results also provide an impetus for exploring vibroacoustography in other bone or implant surface imaging applications.
authors.affiliation: Department of Physiology and Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Hermes A S
authors.initials: HA
authors.lastname: Kamimura
authors.forename: Liao
authors.initials: L
authors.lastname: Wang
authors.forename: Antonio A O
authors.initials: AA
authors.lastname: Carneiro
authors.forename: Randall R
authors.initials: RR
authors.lastname: Kinnick
authors.forename: Kai-Nan
authors.initials: KN
authors.lastname: An
authors.forename: Mostafa
authors.initials: M
authors.lastname: Fatemi
mesh_terms: D019644:Arthroplasty, Replacement, Hip; D054459:Elasticity Imaging Techniques / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008488:Medical Illustration; D019047:Phantoms, Imaging; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D013499:Surface Properties