Currently, the Kellgren-Lawrence (KL) grading scheme is the most- widely used and accepted standard for diagnosis of radiographic OA

• Grade 0: No radiographic features of OA are present
• Grade of 1: Doubtful joint space narrowing (JSN) and possible osteophytic lipping.
• Grade of 2: The presence of definite osteophytes and possible JSN on anteroposterior weight-bearing radiograph.
• Grade 3: Multiple osteophytes, definite JSN, sclerosis, possible bony deformity
• Grade 4: Large osteophytes, marked JSN, severe sclerosis and definitely bony deformity