Osteoarthritis

Question 1

Fill in the blanks describing the different types of of arthritis

Answer 1

Question 2

Why is radiographic imaging useful if osteoarthritis is suspected?

Answer 2

to rule out more serious bone conditions
toallow thoroughexamination
to stage the disease radiographically

Question 3

What considerations are there for anaesthetising a fat dog?

Answer 3

Extra fat makes auscultation difficult & palpation of pulses
Longer needles for IM premed
Subcut fat – poor perfusion of adipose tissue
Use lean bodyweight esp for the IV drugs to avoid overdose
Obesity is an inflammatory state.. (ASA II)
Heat stress, pulmonary problems during anaesthesia
Respiratory obstruction – so use a ‘light’ premed

Question 4

If osteoarthritis is suspected, what tests can be done to confirm the diagnosis?

Answer 4

Further manipulation of joints
Diagnostic imaging
Arthrocentesis
Intra-articular or regional blocks (not in smallies)
Arthroscopy
Exploratory arthrotomy

Question 5

What radiographic features will be seen in osteoarthritis?

Answer 5

Joint effusion
Osteophytes
Enthesiophytes
Sub-chondral sclerosis
Sub-chondral cyst
Intra-articular mineralisation

Question 6

Describe the use of ultrasound in osteoarthritis

Answer 6

Good for peri-articular soft tissue structures, e.g bicipital tendon
Can be used for detection of meniscal tears but requires a very skilled operator

Question 7

Describe the process of arthrocentesis

Answer 7

Single or multiple joints (multiple for detection of polyarthritis)
Aseptic technique
Collection in plain, EDTA and blood culture medium if likely to be infected
Smears for cytology

Question 8

Describe the pathological changes that occur in osteoarthritis

Answer 8

Vascular infiltration and increased osteoclast activity => bone turnover
Cartilage erosion and fissure formation => rough joint surface
Macrophage activation => inflammation
Hypertrophic activation => indicates abnormal cartilage remodelling
Fibrosis and osteophyte formation => stiffness and pain
Protein Activation => cartilage degradation
Prostaglandin E2 (PGE2) increase => pain, lameness and cartilage degradation

Question 9

Describe protein activation in osteoarthritis

Answer 9

• Enzymes (e.g., MMPs/matrix metalloproteinases and aggrecanases) break down collagen and proteoglycans => cartilage degradation

Question 10

Describe the role of PGE2 in osteoarthritis

Answer 10

• levels increase in inflamed joints
• associated with lameness and pain
• contributes to further proteoglycan degradation and inhibits its synthesis=> worsening cartilage damage

Question 11

Describe the treatment of osteoarthritis

Answer 11

Analgesia (NSAIDs)
Lifestyle management: weight loss (if needed), maintaining mobility and exercise, home modifications (e.g., ramps), trim nails etc
Omega 3 supplements (reduce inflammation and cartilage breakdown)

Question 12

What are the 4 options for treating chronic pain?

Answer 12

Physical therapy
Diet, exercise and motivation
Licensed Drugs
Unlicensed drugs

Question 13

Describe anti-NGF (never growth factor) therapy as a treatment for osteoarthritis

Answer 13

NGF is a key player in pain signaling and inflammation in osteoarthritic joints.
It binds to TrkA receptors on nociceptors (pain-sensing neurons), leading to increased pain sensitivity and inflammation.

Monoclonal antibodies (mAb) against NGF bind to NGF, preventing it from interacting with TrkA receptors.
This disrupts the pain pathway, reducing pain perception and inflammation in osteoarthritic joints.