Osteoarthritis

Question 1

What is the epidemiology of OA?

Answer 1

• Most common arthropathy
• F>M
• 80-90% in hips by 80y

Question 2

Which joints are commonly affected by OA?

Answer 2

Main weight bearing joints (spine, hips, knees). Rare in ankle.
DIPs not spared DIP, PIP, 1st CMC).
Asymmetric joint involvement.

Question 3

What is the pathophysiology of OA?

Answer 3

Deterioration of articular cartilage due to local biomechanical factors and release of proteolytic and collagenolytic enzymes. Catabolism > anabolism. Loss of water and proteoglycans exposes bone -> change to bone metabolism.

Question 4

What are the RFx OA?

Answer 4

• Female gender
• Obesity
• Increasing age
• Trauma
• Genetics

Question 5

What are the signs of OA?

Answer 5

• Joint line tenderness
• Bony enlargement at joints
• Deformity
• Limited ROM
• Crepitus on passive ROM
• Inflammation
• Periarticular muscle atrophy

Question 6

What are the symptoms of OA?

Answer 6

Joint pain with motion; relieved with rest. Short duration of stiffness after immobility. With joint instability/locking.

Question 7

What are the radiographic signs of OA?

Answer 7

1) Joint space narrowing
2) Subchondral sclerosis
3) Subchondral cysts
4) Osteophytes

Question 8

Describe OA of the hand.

Answer 8

• DIP (Heberden’s nodes = osteophyts)
• PIP (Bouchard’s nodes - Bouchard’s closer to the BODY)
• CMC (usually thumb sparing)
• 1st MCP (others spared).

Question 9

Describe OA of the hip.

Answer 9

Presents as dull groin pain +/- trochanteric area pain. Internal rotation and abduction lost first. May radiate to anterior thigh.

Question 10

Describe OA of the spine.

Answer 10

Common esp L4/5, L5/S1.
Degeneration of discs and facet joints.
Reactive bone growth may lead to neurological impingement.

Question 11

Rx of OA?

Answer 11

Non pharm: weight loss, rest, PT/OT

Pharm: NSAIDs, glucosamine + chondroitin, injections (steroid/hyaluronic acid), topical NSAIDs.

Question 12

Surgical Mx of OA?

Answer 12

Joint debridement, osteotomy, replacement.

Question 13

Ix in OA work up?

Answer 13

• Bloods (FBE, ESR, CRP): NAD
• ve RF and ANA
• Radiography
• Synovial fluid: non-inflamm

Question 14

Key issues to elicit in ?OA Hx?

Answer 14

• Age
• Time frame: chronic
• Distribution of pain
• Presence of low back pain
• Presence of any neuro symptoms
• Previous injury
• FHx arthritis

Question 15

Red flag conditions relating to hip pain?

Answer 15

Infection, fracture, malignancy

Question 16

Causes of low back pain?

Answer 16

• Facet joint OA
• Disc degeneration/herniation
• Inflammatory back pain: ankylosing spondylitis, psoriatic arthritis, reactive arthritis
• Fractures: osteoporosis, malignancy, trauma
• Infection: discitis, osteomyelitis, epidural abscess
• Intra-abdo pathology: AAA, renal, pelvic

Question 17

Summation shadow of overlapping lumbar vertebrae appearance?

Answer 17

Summation shadows of 2 overlapping lumbar vertebrae in oblique view plain XR said to resemble scotty dog outline.

Question 18

Common cause of spinal canal stenosis?

Answer 18

Usually caused by combination of:

• facet joint OA
• ligamentum flavum hypertrophy
• disc herniation

Question 19

Clinical syndrome caused by spinal canal stenosis?

Answer 19

Lumbar claudication:

• lumbar/buttock/thigh pain
• usually uni- may be bi-lateral
• NOT present at rest
• comes with exercise
• reproducible walking distance
• nerve roots become compressed

Question 20

Back pain Hx features?

Answer 20

1. Site: localised or diffuse
2. Radiation: consider referred (MSK, visceral) and radicular (nerve root irritation).
3. Timing: onset, progression
4. Aggravators and Relievers
   Exclude infection, malignancy, trauma (?#)

Question 21

How do degenerative back conditions usually start?

Answer 21

Traumatic/degenerative disc pathology with vertebral changes developing thereafter (i.e. facet joint OA).

Question 22

What is most recent onset MSK pain due to?

Answer 22

Self limiting musculoligamentous origin