Lecture 8: RA and juvenile arthritis

Question 1

RA radiographical manifestations

Answer 1

Bilateral symmetry

Periarticular soft tissue swelling; fat lines displaced, soft tissue density increases.

Juxtaarticular osteoporosis: inflammatory hyperemia causes epiphyseal and metaphyseal osteopoenia.

Uniform loss of joint space

Marginal erosions (rat bite erosions); loss of cortex at bare areas, no sclerotic border

Juxtaarticular periostitis (occasional), solid or single lamination

Pseudocysts: frequently 4-6 cm in diameter; intraosseous pannus and synovial fluid; simulate subarticular neoplasm or infection.

Articular deformity: joint destruction, ligament laxity, altered muscle function, leads to subluxation or dislocations, ulna Deviation common.

Question 2

RA articular manifestations

Answer 2

Insidious onset of pain, tenderness, swelling and stiffness of joints.

Symptoms worse in the morning.

Bilateral symmetric peripheral joint involvement is hallmark.

Interphalangeal and metacarpophalangeal joints initially affected, with disease progressing proximally.

80% of cases eventually end in the Cx. Spine

Haygarth’s nodes: Rheumatoid soft tissue nodules at MCP joints

Arthritis mutilans: Severe polyarticular destruction and joint deformities.

Baker’s cyst: Fluid filled gastrocnemius-semimembranosus bursa.

“Button Hole”: rupture; rupture of extensor digitorum tendon at PIP joint.

Boutonniere deformity: PIP flexes, DIP extends as extensor digitorum tendon ruptures at PIP joint

Swan Neck deformity: PIP extends, DIP flexes

Mallet finger: DIP fixed in flexion; when extensor digitorum communis tendon ruptures at base of distal phalanx.

Hitchhikers thumb: Boutonniere at thumb.

Question 3

General radiological findings in RA

Answer 3

• Bilateral symmetry
• Periarticular soft tissue swelling; fat lines displaced; increased soft tissue density
• Juxta articular osteoporosis
  
  • • early = demineralisation of bone next to articular surface
  • • late = widespread osteopenia due to
      
      • cortiocosteroid use
      • disuse
• Uniform loss of joint space
• Marginal erosions (rat bite)
  
  • loss of cortex at base of bare areas (areas within synovium but not covered with articular cartilage)
  • no sclerotic border
• Juxtaarticular periostitis; solid or single lamination
• Pseudocysts
  
  • frequently 4-6 cm in diameter, intraosseous pannus and synovial fluid
  • simulate subarticular neoplasm or infection
• Articular deformity: joint destruction, ligamentous laxity, altered muscle function, leads to subluxation of dislocations, ulnar deviation is common

Question 4

Describe this image

Answer 4

Geographic lytic lesion with a narrow zone of transition. Pseudocysts in calcaneus.

Juxtaarticular osteopenia

Entheseal sites also have RA

• Soft tissue swelling under calcaneus
• not an osteophyte, its calcification of soft tissue

Question 5

What is the hallmark sign of RA in the feet?

Answer 5

Lanois deformity (lateral deviation of the toes)

Question 6

RA in the hand

Answer 6

PIP and MCP involved (DIP spared)

First articular sign: Marginal erosion

i) at radial margins of 2nd and 3rd metacarpal heads
ii) Norgaard view (ball catcher) display lucent clefts.
iii) irregular, poorly defined defects, no sclerotic borders.

Early bone sign: juxtaarticular osteoporosis,

i) Epiphyseal and metaphyseal osteopoenia
ii) “dot-dash” interruptions of articular cortex caused by bone mass loss.
iii) Later, osteopoenia extends into diaphysis

Periosteal new bone sees solid or single laminated.

Ivory phalanx: homogenous sclerosis of terminal phalanx (not specific to RA)

Characteristic digital deformities:

Boutonniere deformity

Hitchhikers thumb

Swan neck deformity

Ulnar deviation (ulnar drift)

Zig zag deformity (digital ulnar drift with carpal radial deviation)

Question 7

RA in the wrist

Answer 7

May be first site

60% of cases (wrists can be more severe than hands)

Ulnar styloid erosions (pannus causes subperiosteal resorption)

Carpus: Multiple carpals show erosions, esp. Triquetrum, pisiform

Question 8

RA in the feet

Answer 8

• Feet show initial involvement in 15% of cases
• Big toe interphalangeal joint and all MTP joints involved.
• Fifth MTP most common (then 4th to 1st)
• Marginal erosions more common at medial surfaces
• Lanois deformity: toe flexion deformities with fibular deviations
• Hallux valgus
• May have rheumatoid nodules adjacent to Achilles tendon.

Question 9

RA in the spine

Answer 9

Cx = 80%, Tx = 5%

Cx. usually follows extremity

• AO: Erosions, sclerosis, joints space loss common here.
• AA: 30-50% show atlanto-odontoid involvement
• Atlanto-axial instability: transverse ligament disruption leads to atlas displacement (most common anterior)
• Flexion lateral will show ADI > 3mm

Instability is a late development (usually 10 – 20 yrs.)

Erosions: pannus from adjacent synovium.

• Dens narrowed and vulnerable to #

Intravertebral vacuum cleft sign: gas in vertebral body with osteopenic # or Avascular necrosis caused by corticosteroids.

Question 10

Sub axial RA

Answer 10

• C3- C7
• C2-4 subluxation most common
• Invariably anterolisthesis
• Apophyseal joint erosions, joint space diminution, instability.
• Occasional ankylosis
• Loss of disc height.
• Endplate erosions
• Cortical contour disruptions, except posterior margin.

Bone: Generalized osteopoenia, predisposed to pathological #

Sharpened pencil appearance of lower SP’s.

Question 11

RA in the Hip

Answer 11

35% of patients

In 15% results in protrusio acetabuli (often bilateral)

Axial migration of femoral head.

Secondary degeneration: subchondral sclerosis, osteophytes, femoral head erosions

Prominent generalized osteopoenia

Question 12

RA in the SIJ

Answer 12

Less that 35% of RA patients

Iliac erosions, slightly reduces joint spaces

Little or no sclerosis

Will be unilateral or asymmetrical

Question 13

What condition is this?

Answer 13

Ra, Not OA

• sclerosis is in OA but on the left we can see a slight widening which is indicative of a destructive process

Question 14

RA in the shoulder

Answer 14

Bilateral symmetrical GH and AC involvement

Prominent bursa involvement with increased swelling

Rotator cuff rupture common

Humeral head/ acromial proximity leads to sclerosis, cysts on articulating surfaces and concavity on inferior acromion

Inflammatory synovial erosions near greater tubercle

Resorption of the distal clavicle

Question 15

RA in the elbow

Answer 15

Rheumatoid nodules protrude on forearms extensor surface

Olecranon bursa involvement

Displaced anterior and posterior fat pads

Eventually joint compression undergo osteolysis

Question 16

RA in the Knee

Answer 16

Frequently involved

Prominent suprapatellar and popliteal synovial effusion

Large bakers cyst

Uniform bicompartmental joint space loss (hallmark or RA)

Tibial and femoral peripheral erosions early sign

Frequently see large subchondral cysts

Question 17

RA in the ankle

Answer 17

Mortise and tarsals involved

Swelling, osteoporosis and erosions

Possible ankylosis end stage

Question 18

What are the changes seen in this image? What condition and how old is the pateint?

Answer 18

Juveline Arthritis

Epiphyseal growth plates = child

Swelling around DIP’s

Juxta-articular osteopenia

Cortical thinning

Laminated periosteal response (can see small line between periosteal response and bone/cortex