title: Spectrocolorimetric evaluation of human articular cartilage.
abstract: OBJECTIVE
  The aim of this study was to investigate whether human articular cartilage can be quantitatively evaluated using a spectrocolorimeter.
  
  
  METHODS
  Human articular cartilage specimens were analyzed using a spectrocolorimeter after macroscopic evaluation using the Outerbridge classification. The cartilage characteristics were examined, the L*, a*, b* colorimetric system, the spectral reflectance distribution and the yellow/red spectral reflectance percentage (Y/R SRP). Moreover, the results of the spectrocolorimetric evaluation were compared with the histological score described by Mankin et al.
  
  
  RESULTS
  There were significant differences among the macroscopic four grades in the L*, a* and Y/R SRP values. The spectral reflectance distribution of grade 1 cartilage exhibited a gradual increase in the spectral reflectance ratio as the wavelength increased. The spectral reflectance curves of grades 2 to 4 cartilage had dips at a wavelength of around 580 nm. Across all the measured wavelengths, there were lower reflectance ratios with the progression of cartilage degeneration. Moreover, correlations were observed between the spectrocolorimetric values and Mankin score. A strong relationship existed between Mankin score and he Y/R SRP values.
  
  
  CONCLUSIONS
  The present study is the first to clearly demonstrate the relationship between spectrocolorimetric evaluation and the degeneration of human articular cartilage. The spectrocolorimeter may be a new quantitative evaluation tool for articular cartilage with clinical potential.
authors.affiliation: Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ishimoto
authors.forename: K
authors.initials: K
authors.lastname: Hattori
authors.forename: H
authors.initials: H
authors.lastname: Ohgushi
authors.forename: K
authors.initials: K
authors.lastname: Uematsu
authors.forename: Y
authors.initials: Y
authors.lastname: Tanikake
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Y
authors.initials: Y
authors.lastname: Takakura