Rheumatoid arthritis

Question 1

Radiologic findings of AR

Answer 1

• Periarticular soft tissue swelling.
• Juxta-articular osteoporosis progressing to generalized osteoporosis.
• Uniform loss of joint space.
• Lack of bone formation.
• Marginal erosions progressing to severe erosions of subchondral bone.
• Synovial cyst formation.
• Subluxations.
• Bilateral symmetrical distribution
• Distribution: Hands, feet, knees, hips, cervical spine, shoulders and elbows.

Question 2

Early changes on hands and wrists of AR

Answer 2

• Symmetrical soft tissue swelling, juxta-articular osteoporosis.
• Early marginal erosions: Heads of the MC, PIP, waist of escaphoid, capitate, articulation of the hamate with the base of the 5° MC, and 1° with trapezium, radial and ulnar styloids.

Question 3

Late changes on hands and wrists of AR

Answer 3

• MCP and/or PIP are uniformly involved.
• All the carpals are affected as a unit.
• Uniform joint loss.
• Soft tissue atrophy.
• Diffuse osteoporosis.
• More articular surface with erosions and large subchondral erosions.
• Reductible subluxations at MCP joints.
• Swan neck and boutonniere deformities.
• Subcutaneous rheumatoid nodules.
• Arthritis mutilans.

Question 4

Feet involvement in AR

Answer 4

• 90% of patients with AR.
• Juxta-articular osteoporosis and erosion of the bare areas on the heads of the metatarsals.
• Erosions of bare areas of the heads of the metatarsals.
• Uniform loss of cartilage in MTF joints.
• Progressive erosive changes.
• Erosions: 5° MTC lateral, 1-4° medial.
• Subluxations of the proximal phalanges in a fibular direction.
• Dorsiflexion deformities of the PIP and hallux valgus.

Question 5

Hips involvement in AR

Answer 5

• 50% of patients with AR.
• Uniform loss of the cartilage and axial migration of the femoral head.
• Protrusion acetabulae.
• Symmetrical.
• Osteoporosis.
• Notable abscense of reparative bone and osteophyte formation.

Question 6

Knees involvement in AR

Answer 6

• 80% of patients with AR.
• Bilateral and symmetrical.
• Uniform loss of cartilage in all three compartments.
• There is no reparative response.
• Notable lack of subchondral bone and ostephytes.
• Intraosseous synovial cysts (may form geodes or baker cysts).

Question 7

Ankles involvement in AR

Answer 7

• Bilateral and symmetrical.
• Uniform loss of cartilage.
• Lack of reparative response.
• Erosive changes do not play a prominent role.
• Synovial cysts may be present.
• Periosteal reaction along the posteriorshaft of the tibia.
• DD: Secondary stress fracture or osteomyelitis.

Question 8

Shoulder involvement in AR

Answer 8

• 60% of patients with AR.
• Uniform narrowing of all compartments of the shoulder joint.
• Humeral head migrates proximally and superiorly.
• Generalized osteoporosis.
• No evidence of bone repair or osteophyte formation.
• Synovial cysts may be present, may be mistaken with chondroblastoma.
• Erosion at the distal or proximal end of the clavicle.

Question 9

Elbow involvement in AR

Answer 9

• 34% of patients with AR.
• Bilateral symmetrical involvement.
• Uniform loss of joint space.
• Generalized osteoporosis.
• Lack of reparative bone and osteophyte formation.
• Synovial cysts may be present.

Question 10

Spine involvement in AR

Answer 10

• Cervical spine is affected in 50% of patients with AR.
• Laxity of the transverse ligament of the atlas.
• This becomes apparent in a flexed view.
• Laxity may be so severe as to require posterior fusion.
• > 8 mm of altantodental interval requires surgery.
• More severe: Vertical subluxation of the dens.
• Erosive changes in apophyseal joints.
• Osteoporosis, disk space loss and subluxation at multiple levels.

Question 11

Sarcoiliac joints involvement in AR

Answer 11

• Uniform narrowing of the joint space without evidence of bone repair or osteophyte formation.

Question 12

ATM involvement in AR

Answer 12

• 80% of patients with AR.
• Osteoporosis, joint space narrowing, decreased range of motion, erosions and flattening of the temporomandibular fossa.