Degenerative joint disease

Question 1

How frequent is DJD in cats

Answer 1

DJD is very common in cats
- up to 90% in one study of cats aged > 12 years

Question 2

What is the main risk factor for the development of DJD in cats

Answer 2

The main risk factor for the development of DJD in the cat appears to be advancing age

Obesity will make the clinical manifestations of joint disease by providing a mechanical overload but there is no evidence that it contributes to the development of the condition in cats

Question 3

Are there any breed predisposition for DJD in cats

Answer 3

Certain breeds appear to be predisposed
- Burmese and elbow arthritis

Question 4

What are the main clinical manifestations of DJD in cats

Answer 4

Overt lameness is very uncommon
- the majority of cats with DJD will alter their lifestyle and behavior to cope with the condition

Main clinical manifestations of DJD:
- reluctance to jump
- problems going up and down stairs
- reduced activity levels
- reduced grooming activity
- over-grooming in certain areas due to pain
- difficulties in using litter tray
- playing/hunting less
- less scratching behavior and overgrown claws
- may become less interactive
- may resent handling

Question 5

What are the radiographic evidence of DJD in cats

Answer 5

Osteophytes
- especially where the joint capsules attaches

Osteochondromas
- either free within the joint or attached to the synovium

Possible reduction in joint space due to loss of artiular cartilage

Sub-chondral bone sclerosis beneath the ulnar notch

Soft tissue mineralization, especially around the elbow joint and within the stiffle

Question 6

What are the goals of treatment for cats with DJD

Answer 6

The goals of treatment for cats with DJD include:
- reduction of pain and inflammation
- improvement in joint function
- slowing the disease process if possible

Question 7

What would be your general multimodal approach to treat a cat with DJD

Answer 7

A multimodal approach should consist of:
- Nonpharmacologic therapies:
- nutritional therapy and nutraceuticals
- environmental modification (i.e., providing opportunities for expression of species-specific behaviors)
- other nonpharmacologic therapies (e.g., physiotherapy, laser therapy, …)

- Pharmacologic therapies
    - analgesic and anti-inflammatory drugs
    - chondroprotectants
    - emerging pharmacologic therapies (e.g., anti-NGF antibodies, cannabinoids)

Question 8

Explain how oral or parenteral chondroprotectants may help a cat with DJD

Answer 8

Chondroprotectants have a potential beneficial effect in three primary ways:
- by stimulating and enhancing the metabolism of chondrocytes and synoviocytes, including the provision of substrate to produce cartilage matrix and synovial fluid

- by inhibiting degradative enzymes and other entities, including prostaglandins, complement, and free radicals that play a role in the osteoarthritic destruction of the joint

- by inhibiting the production of thrombi in the microvasculature of the synovium and subchondral bone, which has been shown to play a role in osteoarthritis