Osteoarthritis

Question 1

What are the types of arthritis?

Answer 1

Question 2

What is osteoarthritis, and what are its main features?

Answer 2

Chronic, progressive joint disease characterised by:
- Cartilage breakdown –> joint pain & stiffness
- Inflammation of synovium, worsening joint damage
- Bone remodeling (osteophyte formation & sclerosis)
- Reduced joint mobility & function over time

Common in older dogs/cats but can occur due to trauma, joint instability, or developmental disorders (e.g. hip dysplasia)

Question 3

What are the step-by-step key mechanisms involved in osteoarthritis?

Answer 3

1. Cartilage Breakdown
   - Enzymes (MMPs, aggrecanases) degrade collagen & proteoglycans, weakening cartilage
2. Inflammatory Response
   - Prostaglandin E₂ (PGE₂) increases pain & reduces new cartilage formation
   - Cytokines (IL-1, TNF-α) trigger synovial inflammation & fibrosis
3. Bone Remodeling & Osteophyte Formation
   - Osteoclasts increase bone turnover
   - Osteophytes (bone spurs) develop, restricting joint movement
   - Pores form in subchondral bone, weakening joint structure
4. Chondrocyte Dysfunction & Death
   - Chondrocytes (cartilage cells) become hypertrophic & eventually die
   - Apoptosis accelerates cartilage loss, making OA worse

Question 4

What are the common clinical signs of osteoarthritis in dogs?

Answer 4

Stiffness, especially on rising

Lameness (often shifting or worse after exercise)

Reduced range of motion, joint pain

Muscle atrophy around affected joints

Behavioral changes (e.g. reluctance to play, aggression due to pain)

Question 5

What are the common clinical signs of osteoarthritis in cats?

Answer 5

Reduced jumping ability (struggles to reach higher surfaces)

Grooming changes (over-grooming or poor coat maintenance)

Litter box issues (defecating outside tray)

Subtle behavioral signs (hiding, less interaction)

Question 6

What diagnostic tests can be used to confirm osteoarthritis?

Answer 6

Physical exam: Check ROM, pain, muscle atrophy, joint swelling

Radiographs: Look for osteophytes, joint effusion, sclerosis & cartilage loss

Arthrocentesis: Helps rule out septic or immune-mediated arthritis

MRI/CT: Advanced imaging for soft tissue & early bone changes

Bloodwork & Urinalysis: Assess kidney/liver function before NSAIDs

Question 7

What are the key components of a comprehensive osteoarthritis treatment plan?

Answer 7

Pain Management:
- NSAIDs (meloxicam, carprofen, firocoxib, grapiprant)
- Adjuncts: Gabapentin, tramadol, amantadine, anti-NGF monoclonal antibodies

Weight Management & Diet:
- Target weight loss of 1-2% per week
- Omega-3 supplements (improves joint health)

Exercise Modification:
- Controlled walks, swimming, hydrotherapy
- Avoid high-impact activities

Environmental Adaptations:
- Soft bedding, ramps, non-slip flooring, raised food bowls

Surgical Options (for severe cases):
- Total hip/elbow replacement

Question 8

What are the key considerations when prescribing NSAIDs for osteoarthritis?

Answer 8

Pre-treatment bloodwork: Check liver & kidney function

Monitor for side effects:
- GI signs
- Renal issues (PU/PD, dehydration)
- Hepatotoxicity (jaundice, lethargy)

Alternatives: If NSAIDs are contraindicated, consider grapiprant (EP4 receptor antagonist) or adjunct analgesia

Question 9

How should osteoarthritis patients be monitored over time?

Answer 9

Regular follow-ups (every 4-6 weeks initially)

Pain assessment tools

Adjust treatment if needed:
- Increase/decrease NSAIDs
- Introduce anti-NGF monoclonal antibodies
- Consider physiotherapy or acupuncture

Question 10

Label the OA radiograph

Answer 10