title: Inter-observer validation study of quantitative CT-osteodensitometry in total knee arthroplasty.
abstract: BACKGROUND
  Proximal tibial bone quality is an important factor in implant mechanical stability following total knee arthroplasty. Quantitative computed tomography (CT) osteodensitometry has been used to measure the change in bone density post-operatively. We sought to validate the inter-observer reliability of these measurements.
  
  
  METHODS
  Sixteen CT scans were obtained on cadaveric lower limbs. Two observers independently obtained cortical and cancellous bone mineral density measurements from these scans. Eight CT scans were performed with prosthesis in situ and eight without. Results were compared using correlation coefficient and Bland-Altman analysis.
  
  
  RESULTS
  The study showed a high correlation coefficient of greater than 0.990 for all slices. The mean difference between observers falls within two standard deviations of the mean as seen on a Bland-Altman plot.
  
  
  CONCLUSIONS
  Quantitative CT-osteodensitometry is a reproducible method to measure bone mineral density changes about the knee and shows little variation between observers.
authors.affiliation: Department of Orthopaedic Surgery, University of Auckland, Auckland, New Zealand.
authors.forename: Keryn
authors.initials: K
authors.lastname: Reilly
authors.forename: Jacob
authors.initials: J
authors.lastname: Munro
authors.forename: Salil
authors.initials: S
authors.lastname: Pandit
authors.forename: Alexander
authors.initials: A
authors.lastname: Kress
authors.forename: Cameron
authors.initials: C
authors.lastname: Walker
authors.forename: Rocco Paolo
authors.initials: RP
authors.lastname: Pitto
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D015519:Bone Density / Q000502:physiology*; D002102:Cadaver; D006801:Humans; D007720:Knee Prosthesis; D015203:Reproducibility of Results; D013977:Tibia / Q000000981:diagnostic imaging* / Q000502:physiology; D014057:Tomography, X-Ray Computed