Kellgren and Lawrence system for classification of osteoarthritis

The Kellgren and Lawrence system is a common method of classifying the severity of osteoarthritis (OA) using five grades. 

The original paper ¹ graded OA at the following sites and projections:

• hands: posteroanterior
• cervical spine: lateral
• lumbar spine (facet joints only): lateral
• hips: anteroposterior
• knees: anteroposterior
• feet: anteroposterior

Classification

Numerous variations of the Kellgren and Lawrence classification system have been used in research ³. Below is the original description ^1-3:

• grade 0 (none): definite absence of x-ray changes of osteoarthritis
• grade 1 (doubtful): doubtful joint space narrowing and possible osteophytic lipping
• grade 2 (minimal): definite osteophytes and possible joint space narrowing
• grade 3 (moderate): moderate multiple osteophytes, definite narrowing of joint space and some sclerosis and possible deformity of bone ends
• grade 4 (severe): large osteophytes, marked narrowing of joint space, severe sclerosis and definite deformity of bone ends

Osteoarthritis is deemed present at grade 2 although of minimal severity ¹. 

History and etymology

This classification was proposed by Kellgren and Lawrence in 1957 ¹ and later accepted by the World Health Organization (WHO) in 1961 as the radiological definition of OA for the purpose of epidemiological studies ^3,4.