Kellgren-Lawrence grade: Meaning in a Radiology Report

Also written as: K-L grade, Kellgren-Lawrence classification, Kellgren and Lawrence score

The Kellgren-Lawrence grade rates osteoarthritis on X-ray from 0 (none) to 4 (severe), based on bone spurs and joint space narrowing.

What it means

The Kellgren-Lawrence grade describes how much osteoarthritis, the wear-related joint condition, shows on an X-ray, most often of the knee. It looks at four things. Osteophytes are bony spurs at the joint edges. Narrowing of the joint space is a sign of thinning cartilage. Sclerosis is denser bone under the cartilage, and the bone ends can also change shape. Grades run from 0 to 4.

When it matters

Grade 0 means no osteoarthritis and 1 doubtful changes. Grade 2 shows definite spurs with possible narrowing (mild), 3 definite narrowing with several spurs (moderate), and 4 marked narrowing with bone deformity (severe). Grade 2 or higher usually counts as osteoarthritis. The grade does not always match how much a joint hurts. Your doctor weighs it with your symptoms, and higher grades may come up when joint replacement is discussed.

Questions to ask your doctor

Which part of my joint shows the most change?
Does my grade match my symptoms, or could something else cause the pain?
Has the grade changed compared with my earlier X-rays?

General information, not medical advice. What a finding means for you depends on your symptoms, your history and the images themselves, so talk your results through with a doctor.