Osteoarthritis & joint replacement

Question 1

what is osteoarthritis?

Answer 1

A degenerative joint disease of the cartilage (not the joint).
• Limited to the joint itself (no systemic effect).
• It may involve any synovial joint but most common in the hip, knee & hands.

• Most common form of arthritis.

Question 2

types

Answer 2

1) Primary osteoarthritis:
Mainly affects: distal interphalangeal, first carpometacarpal, hips, knees & apophyseal joints of the spine.

Etiology unknown!
Women are more affected.
There may be a hereditary component.

2) Secondary osteoarthritis:
Affects previously damaged joints, more common in weight-bearing joints.
Both sexes are equally affected.

Etiology: fractures, acquired / congenital deformities, joint injury (chondral lesions), diabetic neuropathy (Charcot joints) & avascular necrosis.

Question 3

Clinical presentation

Answer 3

• Characteristic pain, swelling & deformity.
• Dull, aching pain with morning stiffness of the affected joint.
• Pain becomes steadily worse throughout the day & may disturb sleep.
• Acute onset: swollen, hot & painful joint with raised inflammatory markers.
• Look for Heberden’s nodes at the distal & Bouchard’s nodes at the proximal interphalangeal joints.
• Physical symptoms may not correlate with the severity of the radiographic changes so judge each patient on an individual basis.

Question 4

x ray changes

Answer 4

• Loss of joint space.
• Subchondral bone sclerosis.
• Cyst formation (especially at the hip).
• Osteophyte formation.

Question 5

treatment

Answer 5

Relieve pain, improve mobility & correct deformity.
Medical:
• Simple analgesics (paracetamol, codeine) in combination with NSAID’s helps control symptoms & increase mobility.
• Beware of GI bleeding, especially in the elderly & worsening of asthma (drug side effects).
• Radiant heat (infrared light / hot water bottle) frequently helps.
• Weight loss, physiotherapy & aids to daily living (walking sticks, heel raises, raised chair) & household aids should all be in place before contemplating surgery.

Surgical:
This is indicated for pain relief, improved mobility & correcting deformities only when conservative measures have failed.
• Osteotomy: realignment of a joint to unload an arthritic area.
• Arthrodesis: permanent fusion of a joint by excision & fusion, to stop pain.
• Excision: removal of the joint without fusion.
• Arthroplasty: replacement of all / part of the joint surface by an artificial material.