ABOUT ARTHRITIS

Performance limiting, career ending or a manageable condition?

by Dr Kirsten Neil
BVSc (Hons) MACVSc MS Diplomate ACVIM
Specialist in Equine Medicine

Equine Veterinarians Australia

Although we often think of arthritis in human terms, it is a leading cause of lameness and poor performance in horses. Arthritis or degenerative joint disease (DJD) as it is otherwise known, is a disease of normal joints that may have been damaged by a number of factors, such as trauma or the more common “wear and tear” associated with use repetitive concussion. Put simply, arthritis means inflammation of a joint.

A horse’s joint functions to provide mobility and flexibility and is composed of a number of structures – the bone ends, the overlying joint capsule, the synovial or joint fluid which has a lubricating and
shock-absorbing function, and of particular importance the articular cartilage which overlies the ends of the bones within the joint. Although arthritis can affect any and all of these structures, it is primarily a disease of the articular cartilage with the hallmark of the disease process being the progressive, and permanent loss and damage of this specialised cartilage.

The disease is not limited to the elderly or a certain breed, with any breed, age, sex and type of horse susceptible, although it is certainly more common in the middle aged to older horse. Conformational faults can predispose a horse to arthritis in particular joints – bone spavin is often more prevalent in horses with straight hocks or excessively angled hocks. If not attended to correctly, bent legs in a foal will put more strain on that horse’s joints as an adult and can predispose it to arthritis. A horse’s use can also be a factor, with hock arthritis more common in western pleasure horses, dressage horses, showjumpers and eventers. Although the conditions under which a horse is kept will not influence whether a horse gets arthritis or not, they should be considered in a management program.

Arthritis describes a variety of joint conditions ranging from a swollen joint with excessive joint fluid (synovitis) to bone spavin (arthritis of the lower hock joints) to juvenile arthritis (early onset arthritis) to osteoarthritis (OA), the end stage of arthritis where cartilage is destroyed and bone changes occur. Other joint conditions such as osteochondrosis (OCD) and infected joints (septic arthritis) differ from the arthritis referred to in this article, and horses don’t get the true rheumatoid arthritis like people can. Although arthritis is more common in larger joints such as the fetlock, stifle and knee, it can occur in any joint in the body including low motion joints such as the lower hock joints, small joints such as the coffin joint, and even in the back.

IDENTIFYING AND DIAGNOSING
Although lameness is the most common reason why an owner would seek veterinary attention, horses affected with arthritis are not always overtly lame nor do they always have an easily recognisable joint swelling to pinpoint the exact location of the problem. A common history is of a horse with a chronic intermittent low grade lameness or ‘stiffness’. The horse may warm out of this initially but usually the lameness worsens with increasing duration and intensity of exercise. The lameness may improve with rest but recur once training is recommenced. A horse may be worse on one rein or be reluctant to take a particular lead, refuse jumps or have difficulty performing manoeuvres such as flying changes or lateral work that was not previously a problem. Some horses with chronic low grade hock arthritis will present with sore backs. The lameness may also not be obvious when a horse is affected in more than one joint, and in more than one leg.

A complete and thorough veterinary examination is required to diagnose the problem. The horse should be examined at rest to check for swollen joints, reduced range of motion, pain on flexion of the joint or other less specific signs such as muscle atrophy or abnormal hoof wear. A lameness examination follows with the horse examined at the walk, trot and on the lunge in both directions. Flexion tests are often useful – horses with bone spavin usually have no appreciable joint effusion but will have a lameness that is worse after flexion of the hock. An examination with the horse under saddle may also be required. Nerve blocks, including intra-articular blocks, may be necessary to isolate the lameness. Diagnosis of arthritis is based on examination findings and radiographic examination of the affected joints. Radiographic lesions may include narrowing of the joint space, bone spurs, lysis or bone absorption and new bone production.

HEALTHY JOINT	UNHEALTHY JOINT

Early in the disease, there may be no radiographic changes evident – this does not mean arthritis is not present as degeneration of cartilage can still have occurred, it’s just that cartilage doesn’t show up on an xray. Although xray findings will worsen as the disease increases in severity, the severity of the lameness seen doesn’t always correspond with the xray findings. Further tests may be required in some cases to determine where the problem is coming from – in these cases a bone scan (scintigraphy) is extremely useful and can also point out other less clinically obvious joints where bone activity is increased.

In the advanced stages of arthritis, the diagnosis is often straight forward but there is also less that can be done at this stage in terms of treatment. Many high level performance horses will have arthritic changes evident on xrays, even when there has been no history of lameness.

TREATMENT AND MANAGEMENT
As in humans, there is no one treatment that will work for every horse, every time. Although the ideal treatment would provide both relief of the symptoms of lameness and pain and have a disease modifying effect by slowing down the progression of the disease, often a number of treatments and some trial and error are required to find what works for individual horses.

Whilst some horses with arthritis are ultimately retired to a life of paddock rest due to continued lameness, most performance horses can be managed to lead a useful, pain free and successful ongoing career. Of utmost importance is the horse’s comfort level - if it is persistently lame, and in particular this lameness cannot be alleviated with appropriate levels of medication, then retirement is going to be the best option, sooner rather than later. The progression of the disease depends not only on the type and amount of work performed, but also management practices and treatments employed. There are a myriad of treatment options available that can be tailored to suit the needs of an individual horse and the needs and expectations of the rider.

REST
Most horses with arthritis will respond to a period of rest; however, this is often not a practical option during the middle of the competition season. Selecting competitions where the going is good (easier said than done!) or if you don’t have much choice then limit the amount of competitions on hard ground, which increases the concussion on your horse’s legs. This may mean only competing every two to three weeks rather than jumping on hard ground every weekend. Decreasing the horse’s workload is often beneficial but is not useful as the only strategy employed.

CORRECTIVE SHOEING
Corrective shoeing may be helpful in the management of some arthritic horses to reduce stresses and concussive forces on affected joints. For example, for horses with arthritis of the lower hock joints (bone spavin), reestablishing lateromedial hoof balance (stand the horse squarely and look at the foot from behind – often one heel is higher than the other but to be balanced they should be at the same level) is important, as is easing breakover such as rolled toes.

PAIN RELIEF
Some horses require nonsteroid anti-inflammatories (NSAIDs) such as phenylbutazone for both pain relief and its antiinflammatory properties. For the competition horse, prolonged and continued use is not practical, both because of possible side effects (eg gastric ulcers) and the fact that these drugs can return a positive swab. Use of any NSAIDs should be in consultation with your veterinarian and your competition schedule.

Intra-articular medication Often medication is administered directly into the joint to help maintain the high level performance horse at its required level of competition. Which product is used, and how often, depends on the joint involved, the number of joints affected, the competition schedule and on the individual horse. A number of products are available including but not limited to corticosteroids (anti-inflammatory), and hyaluronic acid (HA - a component of normal joint fluid, used to improved viscosity) with these two products usually used in combination. Generally, benefits are seen within two to three weeks and can last for three to twelve months depending on the joint involved, the horse’s level of activity and severity of arthritis. Again, care should be taken as timing in relation to competition is important to prevent a positive swab.

Other injectable medications
There are a variety of medications available, which can be used alone or in combination with other therapies. Drugs administered via intravenous (IV) or intramuscular (IM) injections have the advantage of reaching all joints within the body. Products include those containing hyaluronic acid (HA), PSGAG (Adequan®) and Pentosan®. After the initial course of treatment, how often they are required as a maintenance therapy depends on the product, finances and the individual horse.

Oral medications and nutraceuticals
A number of oral nutraceuticals are available, which are safe and cost effective to use. Nutraceuticals are dietary supplements derived from food that may provide health benefits. They are different from herbs, for instance chondroitin sulphate is made from cartilage and other products are derived from shellfish. These products will not alleviate lameness in severe cases like phenylbutazone can, but are beneficial for many horses and in particular as a preventative and management strategy. Most contain glucosamine and chondroitin sulfate, both of which have antiinflammatory effects as well as helping the cartilage itself. Some new products also contain hyaluronic acid (HA).
A number of herbal products are marketed as a treatment for arthritis – while the oral nutraceuticals such as Cosequin® don’t swab, some herbal products such as those containing Devils Claw may.

ADAPTING TO ARTHRITIS
The prognosis for the horse affected with arthritis depends on a number of factors – how advanced the disease is, the number of joints affected, the horse’s intended use and in particular what you as the owner or rider expect. Most horses, especially in their teens, that have been out competing at high levels for a long time will have some degree of arthritis – it doesn’t mean their career is necessarily over but that careful management and planning is required in consultation with your vet to extend their competitive career. Regular monitoring by your vet is recommended – the treatment and management plan will need to be tailored based on how the horse is responding and its competition schedule. Sometimes a change in discipline or a reduction in exercise intensity is required - a high level three day eventer that can no longer stand up to the demands of the sport may excel as a schoolmaster, junior or pony club horse when the intensity and demands of exercise has been dropped.

NEW TREATMENT OPTIONS
Many products are currently being investigated overseas. Cosequin ASU® has been released overseas and contains glucosamine and chondroitin sulfate and an extract of avacodo that appears to be beneficial to reduce lameness severity (note this is not the same as feeding avacados as they are toxic to horses).

Other treatments including gene therapy are showing promising results. Diagnostic techniques, including those from blood tests, are also being developed which may aid in earlier diagnosis of arthritis before clinical signs are obvious. At present, such tests are costly and not available to the general horse public, only for research purposes.

In Australia new products are also being released.

Tildren®: Newly available in Australia, the active ingredient in Tildren® is tiludronate, a drug which acts by reducing bone resorption. Licensed for use in navicular disease and bone spavin, the product is often used for other conditions such as back pain, although how effective it is remains to be determined. Treatment is costly and it should be remembered that it usually takes two months after a course of treatment before its full benefits are seen.

IRAP®: IRAP is a unique treatment where, under sterile conditions, blood is taken from the horse and incubated to increase and isolate a high level of a protein that blocks inflammatory pathways that are in overdrive in the arthritic joint. The isolated protein can then be injected into affected joints. This treatment is proving to be useful in the treatment of joints that no longer respond to other intra-articular medications. Similarly, platelet rich plasma (PRP) has recently been introduced into Australia and may have similar effects.

About the Author
Dr Kirsten Neil is a specialist in equine medicine and an FEI veterinarian. She has a Masters in arthritis in horses and is currently working in Berwick in Victoria.
For information on Equine Veterinarians Australia (EVA) visit the web site: www.eva.org.au

READERS STORY - Celery Seed by Natalie Burwood, SA
When lameness affected our Thoroughbred mare Tangara, the vet diagnosed arthritis and suggested that, considering her grand old age of 25, we should make her comfortable and pain free with the use of a sachet of phenylbutazone (bute) powder each day. This treatment was successful and it was only on the odd few days in winter that we needed to increase her dosage to deal with pain or lameness.

After two years of this treatment we were concerned about the effects of the continual use of bute and the possibility of ulcers or other digestive upsets occurring. She didn’t appear to be ill but she was a little ‘depressed’ (if we can steal a human term) although she was eating reasonably well. Our long term farrier commented that he thought she was on her last legs and he offered to do her trims for free until she went.

Just after this we started investigating alternative treatments and were told that celery seed worked very well for arthritis sufferers.

As a trial, we purchased a 1 kilo bag of seeds and proceeded to prepare this to the receipe provided - one cup of celery seed and two cups of water, simmered until the liquid reduced to one cup and then strained so the final product was a bowl of cooked seeds and a bowl of celery ‘juice’.

The seeds were mixed into the feed on one night and the next night the juice was used - which was wonderful as it meant that it was only every second night the ‘pong’ of cooked celery permeated every room in the house.

We had been told that the celery took a while to take effect so we continued with the bute for a week and then over a two week period we gradually weaned her off this and watched for any return of the lameness. Nothing. So, for the next six years we lived with the smell of celery and watched our old mare enjoy her pain-free lifestyle. She had a healthy appetite - usually cantering up for dinner every night, a clear eye and a magnificent dappled coat. And, every six weeks the farrier arrived and gave her a free trim, despite being told that we didn’t expect him to continue doing this. He said it was teaching him a good lesson to keep his thoughts to himself.

Twice in those six years we had felt the need to use bute as well as the celery seed for a couple of weeks each time, but Tangara remained a pain free, healthy horse until the day she passed away at the grand old age of 34. We don’t know why celery seed worked on our mare or if it will work on others but we wouldn’t hesitate to use it again (in conjunction with bute if needed) if we had another horse diagnosed with arthritis.