Which feature is characteristic of Kellgren-Lawrence grade 4?

Which feature is characteristic of Kellgren-Lawrence grade 4?

• A. Large osteophytes
• B. Definite joint space narrowing
• C. Severe sclerosis and definite deformity of bone ends
• D. Moderate osteophytes

Answer: (C)

In Kellgren-Lawrence grading, the most advanced stage shows marked structural changes in the joint, especially severe sclerosis of the subchondral bone and a definite deformity of the bone ends. This combination reflects end-stage osteoarthritis with irreversible remodeling of the joint surfaces. While osteophytes and joint space narrowing can appear in earlier grades, the key feature that distinguishes the highest grade is the clear deformity of the bone ends paired with severe sclerosis. Therefore, this description best matches grade 4.

In Kellgren-Lawrence grading, the most advanced stage shows marked structural changes in the joint, especially severe sclerosis of the subchondral bone and a definite deformity of the bone ends. This combination reflects end-stage osteoarthritis with irreversible remodeling of the joint surfaces. While osteophytes and joint space narrowing can appear in earlier grades, the key feature that distinguishes the highest grade is the clear deformity of the bone ends paired with severe sclerosis. Therefore, this description best matches grade 4.