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Overview of Canine Arthritis
Osteoarthritis (OA), the most common type of canine arthritis, is also commonly known as “old dog arthritis” or “Degenerative Joint Disease” (DJD). Osteoarthritis in dogs is a chronic, progressive, degenerative disease of the synovial joints which results in damage to the articular cartilage and other changes to the joints. Osteoarthritis can occur at any time of life, but incidence tends to increase with age.
Dogs with osteoarthritis typically present with a limp, which is often more pronounced in cold or damp weather and will tend to deteriorate over time. The following signs also suggest that your pet may have arthritis and warrant a trip to the local vet: • Reluctance to walk, run, climb stairs, jump, or play
The Synovial Joint
The Synovial JointWhen trying to understand how any disease is affecting an animal, it is vital that one first understands what is “normal”. This section looks in reasonable depth at the normal structure and function of synovial joints in the dog.The body contains 3 main types of joints. These are:
Synovial joints are the most common and most moveable types of joints in the canine body. The main distinguishing feature of a synovial joint is a capsule which surrounds the joint and is filled with a straw coloured, viscous fluid called synovial fluid. Synovial fluid functions to lubricate the joint, making normal movements smooth and pain-free.
There are 3 components of a synovial joint: Common examples of synovial joints include the knee (stifle), the hip, the elbow and the shoulder. It is these synovial joints that are affected by osteoarthritis. Articular CartilageArticular cartilage is a durable, rubbery substance that covers and cushions the ends of bones in the body.The main functions of articular cartilage are to facilitate the movement of one bone against another and to act as a ‘shock abosorber’. It has a very low friction co-efficient and has properties that make it able to withstand enormous forces. It is a smooth, white with a bluish tinge, glistening tissue and is also commonly known as hyaline cartilage. Osteoarthritis causes the progressive degradation of this cartilage cushion on the ends of bones, leading to pain, stiffness and sometimes inflammation when the joint is moved, as the bones begin to grind on each other.
Causes (Aetiology) and Disease Process (Pathogenesis) of OsteoarthritisAs with many disease processes, osteoarthritis can be classified as primary or secondary.Primary osteoarthritis occurs independently in the body; that is, there are no predisposing events which cause the onset of the disease. Primary osteoarthritis is often referred to as “old-age arthritis” or “wear and tear arthritis” Secondary osteoarthritis occurs as a result of another change within the body. Causes of secondary osteoarthritis include obesity, injury, infection of the joint, congenital abnormalities (present from birth) and joint surgery. Diagnosis of Canine OsteoarthritisDiagnosis of canine arthritis is usually made on the basis of clinical examination findings, radiographic appearanceof the joint, other laboratory tests and individual case history, therefore it is virtually impossible to make a positive diagnosis of osteoarthritis without your dog being examined by a qualified veterinarian.When a vet does a clinical examination on your dog, he or she will be looking for signs of the following: Pain – this is present in nearly all cases of canine arthritis. A vet can manipulate joints that are suspected to be affected in order to elicit a painful response. The most obvious way of telling that your dog has a painful leg is when he or she is limping. Stiffness – often a dog with canine arthritis will be stiff after getting up in the morning. This can be particularly noticeable in cold or damp weather Swelling – swelling of the joint can come and go in osteoarthritis, when it is present, the affected joint will often be warm to the touch from the increased blood flow to the area. Crepitus – whilst moving the joint through its normal range of motion, a vet will be able to feel for crepitus in animals afflicted with canine arthritis. Crepitus is a grating feeling or crackling sound which is caused by one bone grinding on another or on roughened cartilage. Deformity – in advanced cases of cartilage loss, there may be changes in the overall appearance the affected joint. This is due to the growth of bony processes as the body attempts to stabilise the unstable joint and to the loss of articular cartilage. This section outlines the following:
Treatment of Canine OsteoarthritisThere currently is no cure for canine arthritis, however there are a range of therapeutic options available to slow the disease progression and to alleviate much of the pain and disability caused by the disease. Before treatment begins, it is important that you have the correct diagnosis. This will invariably mean a trip to the vet if you believe your dog may have osteoarthritis. The choice of treatment will depend on the severity and nature of your dog’s arthritis, so will be different for each patient.As with many canine illnesses, treatment falls under 3 main umbrellas. These are: • Conservative Treatment– this type of treatment does not involve the use of any drugs or surgery. It generally revolves around diet, exercise and lifestyle alterations to treat the disease. Other conservative treatment includes the use of dietary supplements containing active ingredients such as glucosamine and also the use of specially designed elevated dog bowls • Medical Treatment – this type of treatment involves using drugs to cure, halt the progression of, or alleviate symptoms of the disease. Common medical treatments include the use of pain relievers such as paracetamol, non-steroidal anti-inflammatories such as Aspirin, Rimadyl (carprofen), Zubrin (tepoxalin) and Metacam (meloxicam) and corticosteroids such as Prednisone. • Surgical Treatment– this type of treatment uses surgery to actively try and fix mechanical problems associated with the disease process
Predisposition to Canine OsteoarthritisOne of the major preventable factors which may predispose your dog to developing canine arthritis is being overweight or obese. Obesity leads to far greater than normal forces being applied to joints during periods of moderate to intense exercise. Actions such as jumping out of the car boot for fat dogs can lead to severe joint trauma. Obesity is particularly problematic in larger breeds of dogs, as the weight their joints have to bear is already so high. For more information on obesity and its role in canine arthritis, have a look at the section on conservative treatment on the treatment page.Genetics can also play a part in the development of canine osteoarthritis, but it is a polygenic trait, so modes of inheritance are not as straightforward as they are with many other diseases.
FAQ's about Canine Arthritis
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