Radiographic classification of osteoarthritis

Radiographic Classification of Osteoarthritis

Healthy hip joint

The radiographic classification of osteoarthritis (OA) is a crucial aspect of diagnosing and assessing the severity of this degenerative joint disease. Osteoarthritis is characterized by the breakdown of articular cartilage and changes in the underlying bone, leading to pain and stiffness in the affected joints. Radiographic imaging, particularly X-rays, is commonly used to evaluate these changes and classify the severity of the disease.

Kellgren and Lawrence System

The Kellgren and Lawrence (K&L) system is one of the most widely used methods for classifying osteoarthritis on radiographs. It was developed in the 1950s and provides a standardized way to assess the presence and severity of OA based on specific radiographic features.

Grading System

The K&L system classifies osteoarthritis into five grades:

• Grade 0: No radiographic features of osteoarthritis are present.
• Grade 1: Doubtful narrowing of joint space and possible osteophytic lipping.
• Grade 2: Definite osteophytes and possible narrowing of joint space.
• Grade 3: Moderate multiple osteophytes, definite narrowing of joint space, some sclerosis, and possible deformity of bone contour.
• Grade 4: Large osteophytes, marked narrowing of joint space, severe sclerosis, and definite deformity of bone contour.

Tönnis Classification

Severe osteoarthritis of the hip

The Tönnis classification is specifically used for assessing osteoarthritis of the hip joint. It is based on the degree of joint space narrowing and other radiographic changes.

Grading System

The Tönnis classification includes the following grades:

• Grade 0: No signs of osteoarthritis.
• Grade 1: Mild narrowing of the joint space, slight lipping at the joint margins.
• Grade 2: Moderate narrowing of the joint space, moderate loss of sphericity of the femoral head.
• Grade 3: Severe narrowing of the joint space, severe deformity of the femoral head and acetabulum.

Other Radiographic Features

In addition to the grading systems, several specific radiographic features are commonly assessed in osteoarthritis:

• Osteophytes: Bony projections that form along joint margins.
• Joint Space Narrowing: Reduction in the space between the bones of a joint, indicating cartilage loss.
• Subchondral Sclerosis: Increased bone density beneath the cartilage.
• Subchondral Cysts: Fluid-filled sacs within the bone beneath the cartilage.

Radiographic Assessment of Other Joints

Osteoarthritis of the ankle

While the K&L and Tönnis classifications are commonly used for the knee and hip joints, osteoarthritis can affect any joint in the body. Radiographic assessment of other joints, such as the ankle joint, shoulder joint, and spine, involves evaluating similar features such as joint space narrowing, osteophyte formation, and subchondral changes.

Related Pages

• Osteoarthritis
• Radiography
• Joint space narrowing
• Osteophyte