Osteoarthritis

What is osteoarthritis?

Osteoarthritis (OA), also known as degenerative joint disease, involves progressive damage to the joints. The cartilage lining the joint erodes away and the bone proliferates in response to the damage (similar to the way scar tissue sometimes proliferates in wounds). The joint capsule surrounding the joint can also become thickened and stiff. OA is very common in older dogs, and can also have an early onset in dogs with congenital or traumatic joint abnormalities.

What are the signs of osteoarthritis?

Osteoarthritis tends to be a slowly progressive disease, though signs can occasionally appear to come on suddenly. Affected animals may show the following signs:

• Mild intermittent lameness that slowly becomes more frequent and severe
• Stiff movement
• Difficulty rising and difficulty going up stairs
• Worsening of signs in cold weather, after prolonged rest or after high-impact exercise

Though these signs are common in older animals, they are not 'normal' and we should make an effort to identify and treat them.

What causes osteoarthritis?

Osteoarthritis often results from abnormal stresses within the joint. The most common example of this is hip dysplasia (See Hip Dysplasia Information Sheet), where the 'ball' of the hip does not fit properly into the 'socket'. Trauma can alter the conformation of a joint and lead to progression of osteoarthritis. Obesity can also place undue stress on joints. However, even animals with normal joints can eventually develop osteoarthritis, particularly if they are very active.

How is osteoarthritis diagnosed?

Osteoarthritis is often a 'presumptive' diagnosis, based on history and clinical signs. We will check for joint pain, crepitus (a 'crackly' feeling within the joint that results from bone rubbing on bone), reduced range of motion (resulting from thickening and stiffness of the joint capsule) and any other joint abnormalities. The only way to definitively diagnose osteoarthritis is to take x-rays of the involved joints and identify associated changes, usually under general anaesthesia. However, often we will just treat symptomatically unless we have a reason to suspect that a condition other than osteoarthritis may be causing the clinical signs we are seeing.

How is osteoarthritis treated?

There are several aspects to a successful osteoarthritis management plan. It is important to realise, however, that we are not curing the problem – we are just trying to slow down its progression and provide pain relief.

• Diet: It is important to maintain a healthy weight to minimise pressure on the joints. If your dog is overweight, we will need to formulate a weight loss plan (see Obesity Information Sheet).
• Environment: Be aware that cold weather exacerbates osteoarthritis. Provide warm bedding and consider keeping your dog indoors at night, particularly in winter.
• Exercise: Frequent or high-impact exercise can speed up the progression of osteoarthritis. You should limit off-leash exercise and establish a suitable distance for walks. Start with 20 minute walks and gradually increase the distance you cover. When your dog starts to become lame or tired, you will know you have passed the threshold of how much exercise he or she can handle. Swimming is a great form of exercise, as it uses the muscles without stressing the joints.
• Joint supplements: Adding glucosamine, chondroitin and/or fish oil to the diet helps slow the progression of osteoarthritis by maintaining the cartilage inside the joint and providing a natural anti-inflammatory effect. Alternatively, you can consider feeding Royal Canin Mobility Support diet, which contains these supplements as well as other ingredients to support the joints.
• Pentosan polysulphate: This is a series of four weekly injections followed by three-monthly booster shots. It works in a similar way to glucosamine and chondroitin, by maintaining cartilage health and increasing joint fluid quantity and quality to cushion the joint. It also has a natural anti-inflammatory effect, which provides some pain relief.
• Pain relief medication: We may prescribe an anti-inflammatory medication for your dog to provide pain relief – similar to Nurofen in people (but not the same – do not give your dog Nurofen!). If this is still not enough, there are additional pain relief medications we can try.

If all this is not enough and your pet is still unacceptably painful, there may be surgical options. This will depend on the joints involved and any underlying musculoskeletal disease.