Osteoarthritis

Question 1

Define Osteoarthritis

Answer 1

Asymmetrical degenerative disease due to wear and tear of heavily used joints

Question 2

Aetiology of Osteoarthritis

Answer 2

Unknown aetiology

Primary (idiopathic): no preceding injury to the joint

• Localised: hands, knee, hip, foot
• Generalised: hands and another joint

Secondary: antecedent insult to the joint e.g. congenital abnormality (hip dysplasia), trauma, inflammatory arthropathies, strenuous physical activity

3 components:

1. Cartilage degradation/degeneration
2. New bone formation
3. Inflammation - synovitis/effusion

Question 3

Risk factors for Osteoarthritis

Answer 3

>50
Female
Obesity 
Genetics
Manual occupation
Knee malalignment

Question 4

Symptoms of Osteoarthritis

Answer 4

Joint pain on movement (weight-bearing joints e.g. knee, hip, hand, lumbar, cervical spine | associated with activities | worse after use | better on rest)
Early morning stiffness (<30 minutes)
Functional difficulties e.g. knee giving way or locking
Swelling, synovitis
Bony deformities on the hand

Question 5

Signs of Osteoarthritis

Answer 5

Bony deformities:

• Bouchard’s nodes: enlargement of the proximal interphalangeal (PIP) joints
• Heberden’s nodes: Enlargement of the distal interphalangeal (DIP) joints
• Squaring at the thumb base

Limited range of joint motion
Malalignment, esp. in the knee (knock-knees/genu valgum or bow-legs/genu varum)
Tenderness
Crepitus 
Antalgic gait (limping due to pain)

Hand osteoarthritis often spares the MCP and involves the PIP and DIP joints

Question 6

Investigations for Osteoarthritis

Answer 6

Clinical diagnosis

X-ray: Loss of joint space, osteophytes, subchondral cysts, subchondral sclerosis (LOSS)

CRP/ESR: normal
Rheumatoid factors and Anti-CCP: exclude RA

MRI: cartilage loss, bone marrow lesions, meniscal tears