Reproducibility assessment of different descriptions of the Kellgren and Lawrence classification for osteoarthritis of the knee()

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.