Osteoarthritis

Question 1

What is osteoarthritis?

Answer 1

• result of mechanical + biological events that destabilise normal process of degradation + synthesis of articular cartilage chondrocytes, extracellular matrix and subchondral bone
• >10% of people >60years; more common in women
• usually primary (generalised) or secondary to joint disease or other conditions (eg. occupation, obesity, haemochromatosis)
• risk factors → inc age / obesity / genetics / manual occupation / knee malalignment

Question 2

What are the clinical features of osteoarthritis?

Answer 2

• joint pain / stiffness / swelling
• joint pain is usually worse w/ activities + weight-bearing
• pain and crepitus on movement, with background ache at rest
• not present at rest or at night except in advanced OA
• morning stiffness should be present <30 mins

OA most commonly affects the knee, hip, small hand joints (PIPs + DIPs) and spine (lumbar + cervical).

Question 3

What investigations are done for osteoarthritis?

Answer 3

• X-ray of affected joint
• Serum CRP + ESR → exclude inflammatory arthritis
• Serum RF + Anti-CCP → exclude RA

Question 4

What does X-ray show for osteoarthritis?

Answer 4

‘LOSS’

• Loss of joint space
• Osteophytes forming at joint margins
• Subchondral sclerosis
• Subchondral cysts

Question 5

What are conservative and non-pharmacological treatments for osteoarthritis?

Answer 5

• Weight loss
• Local muscle strengthening exercises
• General anaerobic fitness
• Supports + braces
• TENS
• Shock absorbing insoles/shoes

Question 6

What is the medical treatment of osteoarthritis?

Answer 6

• Paracetamol + topical NSAIDs first-line analgesics
• Topical NSAIDs indicated only for OA of knee or hand
• Second-line → oral NSAIDs/COX-2 inhibitors, opioids, capsaicin cream + intra-articular steroids
• PPI should be prescribed w/ NSAIDs + COX-2 inhibitors (these drugs should be avoided if pt takes aspirin)

Question 7

Joint replacement (arthroplasty) remains the most effective treatment for osteoarthritis patients who experience significant pain. 25% of joint replacements are done on under 60s.

What are the surgical techniques, specifically for the hip?

Answer 7

• cemented hip replacement (most common) → metal femoral component cemented into femoral shaft, this is accompanied by a cemented acetabular polyethylene cup
• uncemented hip replacements → becoming more popular, particularly in younger more active pts - they are more expensive
• hip resurfacing → also sometimes used when metal cap is attached over femoral head - often used in younger patients + has advantage that femoral neck is preserved wich may be useful if conventional arthroplasty is needed later in life

Post-operative recovery: Pts receive both physio + home-exercises; walking sticks or crutches used up to 6wks after hip or knee replacement surgery

Question 8

What basic advice should be given to patients who have had a hip replacement operation, to help minimise the risk of dislocation?

Answer 8

• avoid flexing hip >90 days
• avoid low chairs
• do not cross legs
• sleep on back for first 6 weeks

Question 9

What are complications of joint replacement?

Answer 9

• would + joint infection
• thromboembolism → NICE recommend pts receive LMWH for 4wks following hip replacement
• dislocation

Question 10

Osteoarthritis (OA) of the hip is the second most common presentation of OA after the knee. It accounts for significant morbidity and total hip replacement is now one of the most common operations performed in the developed world.

What are risk factors for OA of the hip?

Answer 10

• increasing age
• female gender (x2)
• obesity
• developmental dysplasia of the hip

Question 11

What are features of OA of the hip?

Answer 11

• chronic history of groin ache following exercise relieved by rest
• red flag features suggesting alternative cause include: rest pain, night pain + morning stiffness >2hrs
• Oxford Hip Score is widely used to assess severity

If features are typical then clinical diagnosis can be made, otherwise plain XR is first-line

Question 12

What is the management of OA of the hip?

Answer 12

• Oral analgesia
• Intra-articular injections → provide short-term benefit
• Total hip replacement remains definitive treatment

Question 13

What are complications of total hip replacement?

Answer 13

• VTE
• Intraoperative fracture
• Nerve injury

Question 14

What are the reasons for revision of total hip replacement?

Answer 14

• aseptic loosening (most common reason)
• pain
• dislocation
• infection

Question 15

What are the differences between OA and RA?

Answer 15

Aetiology

Mechanical - wear & tear*

• localised loss of cartilage
• remodelling of adjacent bone
• associated inflammation

Autoimmune

Gender

Similar incidence in men and women

More common in women

Age

Seen most commonly in the elderly

Seen in adults of all ages

Typical affected joints

Large weight-bearing joints(hip, knee)
Carpometacarpal joint
DIP, PIP joints

MCP, PIP joints

Typical history

Pain following use, improves with rest
Unilateral symptoms
No systemic upset

Morning stiffness, improves with use
Bilateral symptoms
Systemic upset

X-ray findings

Loss of joint space
Subchondral sclerosis
Subchondral cysts
Osteophytes forming at joint margins

Loss of joint space
Juxta-articular osteoporosis
Periarticular erosions
Subluxation