title: Reproducibility assessment of different descriptions of the Kellgren and Lawrence classification for osteoarthritis of the knee.
abstract: OBJECTIVE
  To assess the inter- and intraobserver reproducibility of the original version and different descriptions of the Kellgren and Lawrence classification used in epidemiological studies for osteoarthritis of the knee.
  
  
  METHODS
  The study included 72 patients with osteoarthritis of the knee. Three medical members of the Brazilian Society of Knee Surgery were invited to evaluate the images. An intra- and interobserver analysis was conducted, with an interval of one month. The intraobserver agreement was analyzed using the weighted Cohen's Kappa coefficient. The interobserver agreement was analyzed using the Krippendorff alpha coefficient (α).
  
  
  RESULTS
  The intraobserver assessment indicated conflicting results. In the interobserver analysis, the level of agreement was superficial.
  
  
  CONCLUSIONS
  The classification of Kellgren and Lawrence and its variants generated a low reproducibility between observers. The intraobserver analysis showed a lack of uniformity in the use of this classification and its variants, even among experienced observers.
authors.affiliation: Instituto Nacional de Traumatologia e Ortopedia, Centro de Cirurgia do Joelho, Rio de Janeiro, RJ, Brazil.
authors.forename: Felipe Borges
authors.initials: FB
authors.lastname: Gonçalves
authors.affiliation: Instituto Nacional de Traumatologia e Ortopedia, Centro de Cirurgia do Joelho, Rio de Janeiro, RJ, Brazil.
authors.forename: Felipe Almeida
authors.initials: FA
authors.lastname: Rocha
authors.affiliation: Instituto Nacional de Traumatologia e Ortopedia, Centro de Cirurgia do Joelho, Rio de Janeiro, RJ, Brazil.
authors.forename: Rodrigo Pires E
authors.initials: RP
authors.lastname: Albuquerque
authors.affiliation: Instituto Nacional de Traumatologia e Ortopedia, Centro de Cirurgia do Joelho, Rio de Janeiro, RJ, Brazil.
authors.forename: Alan de Paula
authors.initials: AP
authors.lastname: Mozella
authors.affiliation: Instituto Nacional de Traumatologia e Ortopedia, Centro de Cirurgia do Joelho, Rio de Janeiro, RJ, Brazil.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Crespo
authors.affiliation: Instituto Nacional de Traumatologia e Ortopedia, Centro de Cirurgia do Joelho, Rio de Janeiro, RJ, Brazil.
authors.forename: Hugo
authors.initials: H
authors.lastname: Cobra
keywords: Classification; Knee; Radiography