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Bone Spavin Case Study - Rafiki

Rafiki
NAME:Rafiki
DATE OF BIRTH:1998SEX:MareHEIGHT:14.3 hBREED:HaflingerCOLOUR:Chestnut

Contributors

Mark Moseley BVSc MPhil MRCVS
Mark is a vet at Dukes Veterinary Practice in Aboyne, whom ARC uses as their vet. Mark has a wealth of experience in equine lameness and was responsible for the diagnosis and treatment of Rafiki. He has also been a great source of advice about her shoeing and future management.
Jason Sim AWCF
Jason owns his own farrier company and works in the Aberdeen area. He has been the yard farrier at ARC for five years, and has a wealth of experience shoeing both straightforward horses, and horses with lameness/health problems like Rafiki.
Kim Masson BDes (Hons)
Kim works at the club and has a keen interest in horses, having her own horse at livery with us. Kim created our website and has been working on developing video and animation tools to assist with learning in the equine industry.
Sally McCarthy BHS I.I.SM
Sally runs ARC and is experienced at managing both school and livery horses. Sally is responsible for the selection and purchase of school horses, and creating their individual workload. Sally is also hands on with the finances of the club, so is responsible for setting budgets for veterinary/farrier care and liasing with all suppliers.

Rafiki's Story (Sally McCarthy BHS I.I.SM)

Pre Injury Workload

Post Injury Workload

History

Story Behind Purchase

I bought Rafiki (real name Alea), when we needed a horse suitable of carrying beginner/novices in the riding school. She was bought from a dealer along with 2 other school horses and cost £1400. I decided to purchase Rafiki as she was forward and responsive without being "scary", was a nice size for adults and children and was extremely comfortable to ride. I was confident that she would settle well to riding school work and would suit the environment well, as she would live out, and was the type of horse that would thrive in a busy riding school with lots of attention from members. There were several risk factors with Rafiki.

Risk Factors

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Rafiki clearly has very small, straight joints compared to the size of her body. She is also built "downhill" onto her forehand.

When I took the risk factors into account, I still decided to buy Rafiki, as her temperament, way of going and type outweighed the risk factors.

Was the Risk Worth It?

In short, yes. Whilst Rafiki now has an arthritic condition, she has taught hundreds of people to enjoy riding, have their first canter and enjoy a more forward going horse. She is a real member of the team at ARC and is one of the most popular with our members, who still like to keep up to date with her progress and condition. She has earned in excess of £15,000 in lesson sales in her work with us over the years and whilst this is not pure profit, with overheads (wages/rent/shoeing/vets fees) to come off that figure, she has more than earned her keep and a home for life. She is now enjoying a quieter life, but is teaching a member family how to look after their own horse and giving them a huge amount of joy.

What Does the Future Hold for Rafiki?

Rafiki will have a home with us for life - in buying a "riskier" school horse, with her conformational problems, I committed to providing her with care for the rest of her days. I also believe strongly that horses of Rafikis type and conformation should not be bred from, nor would I ever loan her off site, as I wish to retain control over both her veterinary care and her management.

How did the Problem Present?

Rather than a slow, progressive problem, Rafiki suddenly went lame behind whilst in a lesson. She was in canter, suddenly pulled up on the left rein and did a small buck. This was extremely unusual behaviour for Rafiki and when she was trotted up in hand immediately afterwards, she was lame behind. Rafiki was box rested until the next day, when the vet was booked to come and assess her lameness.

Vet visit and treatment (Mark Moseley BVSc MPhil MRCVS)

Bone spavin is the common name for arthritis of the hock joint and is a common condition in middle aged to older horses. Horses that are overweight, or have bad conformation are more likely to develop bone spavin. Fortunately there are various treatments available to treat the condition.

We were asked to look at Rafiki because she had an abnormal hindlimb gait and on examination she showed moderate lameness in her left hindlimb which did not appear to be coming from her foot. She was overweight and had abnormal conformation in her hindlimbs and the lameness was made worse after a flexion test. A flexion test is done by holding the horse's leg up for at least 30 seconds. Flexion tests are a crude way of putting stress on the joints - if the lameness worsens after a flexion test it makes it more likely that degeneration of a joint is involved. The hock joint is the most commonly affected joint in the hindlimb and at this stage we strongly suspected that Rafiki had bone spavin.

Rafiki was due to have a few months rest over the winter so we made the decision not to give her any treatment but to rest her for three months and to try and reduce her weight. This was easier said than done as Rafiki seems to thrive on fresh air! Unfortunately the rest didn't seem to help much and in the early spring we decided further treatment was necessary.

Usually we would inject the joint with local anaesthetic to confirm that the hock is the source of the pain. In Rafiki's case we decided to go straight for an X-ray to save on costs and because we were very confident that she did have some degree of bone spavin based on her conformation and the clinical examination. X-rays are used to determine which part of the hock is worst affected as the hock is not one joint but a combination of four joints. The lower joints are low motion joints and the top joint is a high motion joint. Fortunately X-rays showed that there were no bony changes in the top two joints of Rafiki's hock as changes to these joints make the prognosis for return to work much worse. X-ray results always have to be interpreted quite carefully as studies have shown that the amount of pain is not necessarily related to the degree of change on X-ray. Some horses can have very dramatic bony changes but very little pain whilst horses that have relatively small changes can be very painful. Rafiki had massive changes to the two lower joints with one of the joints having effectively collapsed but only had a moderate level of pain when we examined her.

Rafiki's hockA "good" hock
Side view Side X-Ray Rafiki's Hock Side X-Ray Good Hock
Front view Front X-Ray Rafiki's Hock Front X-Ray Good Hock
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We made a decision to medicate the two lower joints with a steroid, which acts as a potent anti-inflammatory. Rafiki improved on this treatment plan which confirmed the diagnosis. At this stage we decided to change her shoeing to reduce the strain on the hock joint. Shoeing can help to reduce the amount of medication needed which is very important as the steroids do have side effects so we try to do everything to reduce the amount of medication we use.

Usually medication lasts 2-3 months, however we have had cases that need joint medication as little as once a year. It is important to realise that bone spavin is a degenerative condition and there is little we can do to reverse the changes, but we can manage the symptoms. There are various other medications that we commonly use alone, or in combination with steroids, to treat joint conditions. They act as lubricants for the joint, as mild anti-inflammatories, and some of them claim to regenerate some of the damaged cartilage. They are very expensive with a course of treatment costing up to £500.

Should more conservative treatments not work we can try to destroy the joint either chemically or surgically. This does have good long term results in 80% of cases but it is a drastic procedure and is used as a last resort because it is irreversible and can cause collateral damage. We usually use it in horses that have stopped responding to joint medication.

Skeletal anatomy of the hock

Farrier management for bone spavin (Jason Sim AWCF)

Shoeing Aims

The shoeing plan for any therapeutic case must complement the veterinary treatment and the conformation of the horse. Our aim is to make the horse as comfortable as possible increased comfort will help the horse to move more effectively and lay solid foundations for improvement or at least to slow down the disease progression.

To decide how best to shoe for spavin we have to look at both conformation and how the horse moves. In the case of spavin, shoe wear can also give us indicators of which type of shoe will give us the best results. It must be remembered that with bone spavin our aim is to manage the condition and increase comfort-we cannot repair the joint.

The vet will always deal with the clinical signs but there are a number of specific shoe wear patterns. The toe can be heavily scuffed as flexion in the hock is compromised. The lateral (outside) branch of the shoe is excessively worn out. This is due to the horse trying to unload the inner hock region to be more comfortable. In some cases the whole shoe is worn away very quickly because the horse is sliding its feet along the ground to try and reduce direct concussion up the leg.

Shoeing Options

Traditionally, there are three options available to the farrier.

  1. In mild cases with no specific conformational issues a normal shoe with a set toe will often suffice. It can be useful to use a shoe with less grip as this reduces the 'grabbing' effect as the foot naturally slides.
  2. For horses with base narrow, bow legs or cow hocks a lateral extension shoe can be useful. This can help centralise the forces exerted up the leg and reduce pressure on specific parts of the joints. This would also tend to be fitted with a set toe.
  3. Horses that have good alignment but poor angulation i.e. straight or sickle hocks can respond well to a heel elevation shoe. This is considered quite old fashioned but it still has a place in modern farriery. By raising the heels we change the way in which each joint interacts. This changes how each joint loads and can reduce pressure on any areas of pathology. A set toe is always fitted with this shoe to protect the toe and to increase stability if the shoe on the foot.

A set toe is when the toe of the shoe is turned up, this eases breakover and helps protect the hoof from excessive wear.

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Normal toe shoe Set toe shoe
Normal toeSet toe

Shoeing Rafiki

Rafiki's hind legs are quite straight in both planes so a raised heel shoe was seen as the best option. Initially, a pair of hand forged shoes were made with a 15mm lift. The front of the graduation is angled to reduce grip and increase comfort. Subsequent shoes have been fabricated i.e. cut and welded. This gives the same results but less time is needed to make the shoes. One side effect we must be aware of with any 'lift' shoe is the increased pressure on the heels due to the centre of gravity moving towards the heels. This can cause crushing or bruising of the heels. In Rafiki's case, she has very strong heels so we don't expect this to be a problem. With this in mind, I expect to keep Rafiki in these shoes ad infinitum. Obviously each case has to be judged on its own merits.

Shoeing is a small part of a bigger management plan, so for farriery to be effective it has to be combined with weight control, exercise regime and perhaps appropriate use of nutraceuticals.

Therapeutic shoeing can be quite costly and obviously prices can vary quite dramatically. For Rafiki's shoes there is a £20 surcharge to cover materials and manufacturing time.

Bone spavin is a progressive degenerative disease so there may come a point when we run out of options to keep Rafiki comfortable but so far the response has been very positive.

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How Rafiki moves now