Kellgren and Lawrence system for classification of osteoarthritis
Citation, DOI and article data
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
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.
- 1. Kellgren J & Lawrence J. Radiological Assessment of Osteo-Arthrosis. Ann Rheum Dis. 1957;16(4):494-502. doi:10.1136/ard.16.4.494
- 2. Kohn M, Sassoon A, Fernando N. Classifications in Brief: Kellgren-Lawrence Classification of Osteoarthritis. Clinical Orthopaedics & Related Research. 2016;474(8):1886-1893. doi:10.1007/s11999-016-4732-4
- 3. Schiphof D, Boers M, Bierma-Zeinstra S. Differences in Descriptions of Kellgren and Lawrence Grades of Knee Osteoarthritis. Ann Rheum Dis. 2008;67(7):1034-1036. doi:10.1136/ard.2007.079020
- 4. Sangha O. Epidemiology of Rheumatic Diseases. Rheumatology. 2000;39(suppl_2):3-12. doi:10.1093/rheumatology/39.suppl_2.3