Osteoarthritis

Question 1

Define osteoarthrisis

Answer 1

Progressive disorder of the joints caused by gradual loss of cartilage and resulting in the development of bony spurs and cysts at the margins of joints

Question 2

Changes to joint structure in arthritis:

Answer 2

• Thickened capsule
• Cyst formation
• Sclerosis in subchondral bone
• Shelving ‘fibrilated’ cartilage
• Osteophytic lipping
• Synovial hypertrophy
• Altered contour of bone

Question 3

Changes to articular cartilage in osteoarthritis

Answer 3

Increased swelling
Change in colour
Cartilage fibrillation - fraying and splitting of cartilage
Cartilage erosion down to subchondral bone

Question 4

Molecular changes in articular cartilage:

Answer 4

Water content decreases
Decreased proteoglycan synthesis
Decreased collagen x-linking
Decreased size of aggrecan, GAG and hyaluronic acid
Traumatic damage

Question 5

Pathogenesis of osteoarthrisis

Answer 5

Changes in articular cartilage
Bone remodelling: bone cells cause further degeneration of cartilage though the proteins RANKL, OPG and sclerostin
Inflammation: immune system recognises damage, release of MMPs, viscious cycle causing chondrocytes to break down cartilage

Question 6

Types of osteoarthrisis

Answer 6

Primary: degenerative
Secondary: caused by trauma, hip dysplasia, infection, diabetes

Question 7

Risk factors of osteoarthristis:

Answer 7

Systemic:
- Age: increased risk at older age
- Genetics
- Gender: men less than 50 at higher risk, women at higher risk over 50
- Nutrition: low vitamin C and D intake
Joint Biomechanical Risk factors:
- Joint trauma
- Obesity
- Occupation
- Abnormal joint mechanics
- Knee extensor weakness
- Sports with risk of joint injury

Question 8

Key symptoms of OA

Answer 8

• Pain (especially during load-bearing activities such as walking)
• Short-lived stiffness in morning
• Difficulty moving affected joints or doing certain activities

Question 9

Diagnosing Osteoartritis

Answer 9

Clinical history
- Pain
- Decreased walking distance
- Sleep disturbance
- Limp
- Stiffness
X-ray
- narrowing joint space
- osteophytes (remodelling of bone)
- subchondral sclerosis (increased whiteline in X-ray as cartilage is being worked away)
- cyst formation (cracks in bone leading to synovial fluid penetrating into bone and causing cysts)

Question 10

Management of OA and goals

Answer 10

Slow progressive illness with no cure, so treatment is directed at symtoms and slowing progression
Goals:
- Decrease pain
- Increase range of motion
- Increase muscle strength

Question 11

Non-operative treatments for OA (4)

Answer 11

Medications: pain management (paracetamol, Non steroidal anti inflammatory drugs aka NSAID), alternative medication (drugs used for cartilage repair)
Physiotherapy: increases range of motion, strengthens muscle, aerobic conditioning, weightloss, helps with future surgical outcomes
Walking aids: transfers load to unaffected side
Joint injections: cortisone/ corticosteroid to reduce inflammation more radidly than NSAIDs, viscous supplement to replace synovial fluid. limited effect

Question 12

Surgical treatment for OA

Answer 12

Arthroscopy: inserting camera, limited results
Cartilage transplantation: rarely used, only success in small cases
Joint replacement: partial or full, removes worn cartilage and replaces it with synthetic material, mainly to reduce pain and increase range of motion, improve activities for daily living