Can rheumatoid arthritis (RA) show degenerative changes on x-ray?

Rheumatoid Arthritis Shows Characteristic Degenerative Changes on X-ray

Yes, rheumatoid arthritis (RA) shows specific degenerative changes on x-ray that are characteristic of the disease and help distinguish it from other forms of arthritis. 1, 2

Radiographic Hallmarks of Rheumatoid Arthritis

• The hallmarks of rheumatoid arthritis on radiography include periarticular osteopenia, uniform joint space narrowing, and osseous erosions 1
• Radiographic progression appears to be most rapid in the first 2 years of disease, with 75% of all damage seen in the first 5 years of a 10-year study 1
• The unique combination of osteoporosis, marginal erosions, and relatively minimal reactive bone formation helps distinguish rheumatoid arthritis from other inflammatory arthritides 2

Progression of X-ray Changes in RA

Early Changes

• The earliest abnormalities consist of synovial proliferation, soft tissue swelling, and periarticular osteoporosis 3
• In early disease, radiographs of the hand joints are characterized by soft tissue swelling and mild juxtaarticular osteopenia 4
• Although erosions occur later in the disease course, radiography remains important to identify possible erosions and provide an overview of distribution of disease 1

Advanced Changes

• At a slightly later stage, the inflamed synovial tissue ('pannus') extends across the cartilage surface, leading to chondral erosions and small bone erosions at the joint margin (bare areas) 3
• Marginal and central erosions follow in advanced stages 3
• Finally, fibrous ankylosis, joint deformities (subluxations and dislocations), fractures, and fragmentations are typical findings of more advanced RA 3

Limitations of X-ray in RA Diagnosis and Monitoring

• Plain radiography only visualizes the late signs of preceding disease activity 5
• MRI is much more sensitive than radiographs for identifying erosions in RA 1
• MRI detection of new erosions preceded conventional radiography by a median of 2 years 1
• Ultrasound is more effective for erosion detection than conventional radiography, with comparable efficacy to MRI 1

Clinical Implications and Monitoring

• The periodic evaluation of joint damage, usually by radiographs of the hands and feet, should be considered for monitoring disease progression 1
• With CT as the reference technique, conventional radiography was shown to have an accuracy of 81% for detecting erosions, compared to 89% for MRI and 80% for ultrasound 1
• Radiographic progression in established RA gives an objective measure of anatomical damage that defines the course of the disease and the long-term effects of treatment 6
• Between 60-73% of hospital-based RA cases develop one or more erosions in the hands and wrists within 12 months of developing RA 6

Advanced Imaging Techniques for RA

• MRI with intravenous gadolinium has been shown to be more sensitive compared with ultrasound and has a higher diagnostic performance, especially in the early stages of rheumatoid arthritis 1
• The finding of enhancing bone marrow "edema" (osteitis) on MRI studies in patients with early RA is proving to be the best single predictor of future disease progression and functional deterioration 1
• Ultrasound outperforms clinical evaluation in detection of inflammation and structural damage of rheumatoid arthritis 1
• CT, although more sensitive in detection of erosions compared with radiography and MRI, is not routinely used and is limited in the ability to show synovial hypertrophy and other soft tissue abnormalities 1

Pitfalls and Caveats

• Joint involvement patterns must be carefully evaluated as rheumatoid arthritis characteristically affects metacarpophalangeal, proximal interphalangeal and wrist joints, while distal interphalangeal joints are typically spared 7
• Conventional radiography remains the standard imaging technique for joint studies in patients with suspected RA, but may miss early disease 3
• When evaluating a patient with chronic wrist pain and normal or nonspecific findings on radiographs, MRI should be considered if inflammatory arthritis is suspected 1
• Joint aspiration may be necessary to exclude infection when evaluating chronic wrist pain with nonspecific arthritis findings on radiographs 1, 8