Imaging (arthritis)

Question 1

What joints are affected in osteoarthritis?

Answer 1

Joint involvement often assymetrical
(eg right hip, left knee)
Usually affects weight bearing or active joints
(spine, hip, knee, thumb base, DIP)
Sometimes affects other joints where:
    overuse
    previous injury
    previous arthritis

Question 2

What does loss of joint space on imaging show?

Answer 2

Osteoarthritis

Question 3

How are cysts in bone formed?

Answer 3

Synovial fluid dissects into bone, forming cysts

Question 4

What leads to marginal osteophyte formation?

Answer 4

Periosteal stimulation

periostium causes more bone to form at joint margin

Question 5

What joints are affected in rheumatoid arthritis?

Answer 5

Joint involvement usually symmetrical

Can affect any synovial joint but commonly:
    MCP, MTP
    PIP (not DIP)
    Wrists, hips, knees, shoulders
    Atlantoaxial joint (C1/2)

Question 6

What radiological features are seen of rheumatoid arthritis?

Answer 6

Synovial proliferation and reactive joint effusion causes soft tissue swelling

Hyperaemia causes bone demineralisation resulting in periarticular osteoporosis

Inflammatory pannus destroys bone, initially at the joint margins

Capsular and ligamentous softening allows joint subluxation and deformity

Exposed eroded bone ends may fuse (ankylosis) (rare)

Question 7

What radiological features are seen of seronegative arthritis?

Answer 7

Sacroiliac joint and spine involvement

Ill-defined periarticular bone formation

Tendency to joint ankylosis

Question 8

What is “ankylosis”?

Answer 8

Abnormal stiffening and immobility of a joint due to fusion of the bones

Question 9

What scan shows increased vascularity around joints (accompanies synovitis)?

Answer 9

Isotope bone scan

Question 10

Thickening of synovium and increased blood flow within it can be demonstrated by:

Answer 10

Colour Doppler ultrasound