Table 1.

Kellgren-Lawrence grading scale

Standard	Performance
Grade 0	No obvious irregular changes on X-ray
Grade l	Suspected joint space narrowing or suspicious osteophyte formation
Grade II	Obvious osteophytes with mild joint space narrowing
Grade III	Moderate osteophytes, narrow joint space, mild subchondral sclerosis, and small extent of bone changes
Grade IV	Extensive osteophytes, severely narrowed joint space, obvious bone sclerosis, widespread subchondral changes, and marked joint hypertrophy and deformity