You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Arthritis is a common disease of the joints which can affect individuals of any age. At the present time there is no cure.

The term "arthritis" literally means joint ("arthr..") inflammation ("..itis). However, there is often confusion because people use different terminology to describe the same condition, for example :the terms "osteoarthritis" (literally means inflammation of bones ("osteo..) and joints) and more recently a new term - "degenerative joint disease" (or DJD) are both in common use. To save further confusion we shall called the disorder "arthritis" throughout this article.

Several tissues in and around joints are involved in "arthritis" including cartilage, bone and the soft tissue joint capsule. These tissues react very differently to an insult - for example, because cartilage does not have a very good blood supply it can not respond to injury in the same way as other tissues when it is damaged, and the cartilage degenerates. The inner lining of the joint capsule (called the synovial membrane) on the other hand can develop typical inflammation (with movement of fluid and blood cells into the tissue) because it has a good blood supply..

Damage to the cartilage (the white knuckle part that you will see on the ends of bones)  is extremely serious because it is designed to allow free movement between the bones in the joint, and if damaged (as it is in arthritis)  it will eventually lead to loss of function in the joint. But this disease is not new - fossil evidence tells us that serious joint disease has plagued living creatures for a very long time because it was present in reptiles as long ago as the Mezozoic period - but why does it occur ?

There are basically two types of arthritis :

• Primary. Deterioration of the cartilage occurs with advancing age. Signs occur in older animals
• Secondary. There is an insult on the joint of some type and clinical signs can occur at any age :
  • Local insult - eg trauma or rupture of a ligament, introduction of infection
  • A generalised disease condition which involves the joints eg immune disorders such as SLE.

There can be both inflammatory and non-inflammatory causes of arthritis :

• Inflammatory causes
  • Infections (bacteria, viruses, fungi, protozoa)
  • Non-infectious causes
    • Immunological causes (rheumatoid arthritis, SLE)
    • Non-immunological causes (bleeding into the joint)
• Non-inflammatory causes
  • Trauma
  • Abnormal biomechanics on the joint (eg hip dysplasia, ruptured ligaments)
  • Others (eg neoplasia, aseptic necrosis eg Legg Calve Perthes disease)

The signs of arthritis include :

• Lameness
• Abnormal gait
• Stiffness for hours after exercise
• Inability to perform usual activities - eg climbing stairs, jumping up into the car
• General reluctance to exercise
• The joint may show - swelling, local pain and increased temperature to the touch.
• If the joint is moved grating can sometimes be felt, and sometimes there is a loud crack or click
• With advancing arthritis the range of movement in the joint is reduced

The changes that occur within the joint can progress quite rapidly, some of the changes being seen only 7 days after injury to a joint. Evidence of arthritis can be seen after only 5 weeks on XRays.

This dog has severe hip dysplasia with secondary arthritic changes- some of which are described below 

A  Abnormal, square shaped head to the femurs with a broader than normal neck. The head "ball" is not lying properly in the acetabular fossa

B There is a lot of "new" bone around the joints such as this osteophyte lying in front of the acetabulum

C There is a loss of cartilage on the surface of the joint resulting in a loss (or narrowing) of apparent joint space between the head of the femur and the acetabulum

D There is an increase in the radiodensity of the bone lying under the acetabulum articular surface. This gives the bone a very white colour - and is called sclerosis. In addition, the joint space (darker line)  appears to be wider because the head of the femur is partially lifted out of the socket created by the acetabulum.

E New bone can be deposited all around the joint, including along the neck of the femoral head.

There is no cure for arthritis - although there are hopes for new treatments such as gene therapy.

Treatment is aimed at :

• Reducing inflammation
• Removing pain
• Slowing progression of the disease
• Assisting repair of damaged tissues
• Maintain joint function

Treatment usually involves the long term administration of drugs, and in some cases surgery to correct biomechanical problems. If long term drug therapy (for example with non-steroidal anti-inflammatory drugs (NSAIDs) is needed it is important to minimise the dosage and frequency to reduce the risk of side-effects developing. Patients often have recurrent episodes even if they do respond to initial medical treatment

If normal function cannot be maintained surgery is sometimes performed to stabilise or fuse the joint (called arthrodesis), and so remove the discomfort associated with movement.

The signs of arthritis can be much worse in obese animals, and there are excessive forces on joints in animals that are obese so weight loss is a priority in these patients.

Nutritional Supplements There is some  evidence to support the use of nutritional supplements including  the Omega-3 (n-3) polyunsaturated fatty acids such docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) which are found in marine fish oil, in the management of arthritis. These are thought to have an anti-inflammatory effect, and possibly delay the progression of osteoarthritis by inhibiting the action of local enzymes released into the joint - the so-called matrix metalloproteases or MMPs. A combination of glucosamine and chondroitin is also widely used in the management of osteoarthritis. These are both important structural components of the joint, and their concentrations increase in the joint tissue when dietary intake is increased.

Exercise is important for joint function to be maintained - so regular walks are important. But excessive exercise must be avoided as this can increase damage within the joint. Each individual should be managed differently ...but some lead exercise periods are necessary or the muscles will waste (atrophy) around the joint making return to function unlikely.

Last updated : September 2013