Osteoarthritis is a progressive deterioration within joints (also called degenerative joint disease (DJD) in veterinary medicine). There is degeneration of the cartilage lining the ends of bones, changes of the underlying bone at joints and changes of the joint capsule that secretes the joint fluid. These changes are seen in most older patients at some stage and can also be seen in young animals associated with inherited or growth disorders (e.g. hip dysplasia, patella luxation), or resulting from trauma (e.g. fracture, dislocation or ligament injury).
SIGNS OF OSTEOARTHRITIS
Intermittent lameness that slowly becomes more frequent and severe is the usual sign. Stiff movement, difficulty rising and difficulty going up and down stairs are also common signs. Exercise can result in increased lameness, as can lying down for long periods and cold weather. As these signs develop gradually it is often easy to accept them as signs of old age (when seen in older patients), rather than as signs of our pet suffering treatable pain associated with osteoarthritis.
CAUSES OF OSTEOARTHRITIS
Causes of osteoarthritis in young patients include inherited or growth disorders (e.g. hip dysplasia, patella luxation, OCD), or trauma (e.g. fracture, dislocation or ligament injury). In older patients, long term exercise and ageing are the cause, therefore working, athletic and overweight pets are more likely to suffer osteoarthritis at a younger age.
The history of signs seen by you are important in diagnosis of osteoarthritis in your pet. Other possible causes of this type of lameness are immune-mediated arthritis (e.g. rheumatoid arthritis), infectious arthritis or a tumour. X-rays are often taken, and in most cases a general anaesthetic is required to allow the proper positioning for good quality diagnostic radiographs to be produced. In some cases, analysis of fluid from within a joint or biopsy of tissues within the joint may be needed.
TREATMENT OF OSTEOARTHRITIS
Treatment of osteoarthritis is palliative i.e. designed to relieve the clinical signs, and in some cases, slow the progression of osteoarthritis, but the degeneration within the joint is permanent and will continue. Many owners find it difficult to remember how their pet was before arthritis set in because it happens so gradually. We are often asked how to assess pain because our pets don’t complain by vocalising (yelping, crying etc.). Your pet is definitely in pain if they are showing the signs of arthritis: limping, sore after exercise, getting up or down gingerly (slowly), or won’t (can’t) climb steps to do something you know they would like to e.g. greet you or get to their food. This pain is constant and our pets very stoic, so these signs are the only way to assess how painful the arthritis is, and if seen the pain should be treated. Response to medication in most cases is excellent, and many owners are quite surprised at how much more active and mobile their pet becomes.
Two types of medical treatment exist.
(i) Reactive treatment - Non-steroidal anti-inflammatories (pain relief) is available in oral tablets or liquid form. This type of medication gives very good results but has the disadvantage of needing daily or twice daily dosing, and not having long term effect.
(ii) Proactive treatment - This type of medication aims to improve the function of the joint for longer periods. There are two main types:
- Pentosan is frequently used as a course of 4 injections given at 7 day intervals. These injections treat the pain of osteoarthritis, but also slow the ongoing degeneration by protecting the cartilage, and improving the quality and amount of joint fluid (which provides lubrication and nutrition to the tissues of the joint) in all the joints of the body. An excellent response in usually seen with this medication. Duration of effect is variable, often related to the initial severity of signs. Further treatment is tailored to the individual, some patients may be extremely comfortable for 6-12 months before requiring a repeat course of injections, others may deteriorate after 1 to 2 months and require a single injection to be given every 1-2 months. Some animals need ongoing pain relief as well as the injections.
- Neutriceuticals (dietary additives) - typically extracts of shark cartilage and green-lipped mussel. Green-lipped mussel (GLM), has been traditionally used in treatment of arthritis for the past 25 years. GLM has been proven to reduce pain and swelling, with visible improvement in daily activity evident after feeding the diet for only 6 weeks. It also has glycosaminoglycans - which is a vital joint nutrient and is also what Pentosan (see above) is designed to enhance and stimulate, so often both these 2 treatments are used together.
- Improvement with these treatments is usually gradual over several weeks, so additional pain relief may also be given at first. However, we often find that dogs that required pain medication daily, are able to reduce the dose required, and sometimes come off the medication altogether with long term treatment.
Sometimes when the diagnosis of osteoarthritis is made an underlying cause is also diagnosed, such as hip dysplasia, cruciate ligament rupture or patella instability, which may need surgical treatment.
HOME CARE OF ARTHRITIC PATIENTS
Activity should be restricted to a level that doesn’t aggravate the condition. If your pet is sore after a walk you should try shorter walks or if chasing the ball makes things worse play for less time or not at all. Swimming is an excellent form of exercise as it is non-weight bearing, and puts less stress on joints, but cold aggravates osteoarthritis so a warm pool is needed.
Cold should be avoided as much as possible. Arthritis will always be worse in winter. If your pet can sleep inside especially overnight this will help. Otherwise, try to minimise exposure to cold by providing thick warm bedding (ideally not on concrete), a warm sheltered area (e.g. kennel or shed), even consider a warm dog coat for winter.
Being overweight puts added pressure on joints, increasing pain and degeneration. It is very easy for an arthritic patient to become overweight as their activity levels decrease due to their pain and ageing. Overweight pets need to be dieted - please talk to us for advice about this. If you need advice on any of the above topics please call our clinic.