Case Histories

CASE HISTORIES

1. "Little John" the foal

As a ten day old foal Little John had surgery for a severe valgus deformity of the right fore limb.

Born with severe angular limb deformities "Little John" was small and suffering from "windswept conformation" due to his position in the uterus and other congenital factors. Most severe was the toe-out conformation of the right foreleg (the off-fore). This case is an example of how good management combined with attention to farriery detail can be used to maximise the growth potential of a young horse in a successful attempt to normalise conformation. At 2 weeks of age surgery was performed to elevate the growth plates just above the fetlock and carpal joints. At this time Little John was trimmed for the first time and fitted with glue-on front shoes with medial extensions to increase the surface area to the inside of the leg. A severe deviation in the hock was also noted and trimming commenced on all 4 feet to minimise the conformation faults over time. John went home from hospital to a stable from which he did not leave, other than to go to a very small yard with his mother, when the stable was cleaned. He was placed on a low energy, low protein, mineral balanced diet, and mares milk of course. The mare retained good body condition but did not gain weight throughout this time as it is important not to push the growth rates of a foal with this problem. A rapid growth rate will exacerbate the conformation problems in foals. John was trimmed every 2 weeks until 3 months of age with a slow but steady rate of improvement. Further surgery or shoeing were beyond the owner's budget. At 3 months John was moved, with his mother, into a larger yard ( just big enough to move about) with grass and the trimming program was extended to every 3 weeks. At four and a half months the mare and foal graduated to a paddock. By 5 months trimming was extend to every 4 weeks. Improvement in conformation was very slow from 1 - 2 months. Between trims the right fore foot became noticeably longer to the outside (laterally) and the inside heel was shorter and folding under. Conformation began to improve noticeable between each visit from 2 - 4 months, and at 4 - 5 months the foot no longer distorted between trims and the conformation had significantly normalised. John was weaned between 5 and 6 months and shares a paddock with other weanlings. At his last trim his foot had not distorted since the previous trim and his conformation is continuing to improve. He will require monthly trimming by the farrier to minimise his conformation faults, up to and after 12 months of age. The hock and hindlimb conformation problems have also improved over 90% and the prognosis for a normal athletic career and future soundness is good.

Approaching 3 months of age and there is significant improvement. At this stage he graduated to a larger area and the trimming interval was extended to 3-4 weeks apart.

2. Hoof crack


An example of flared feet with many hoof wall cracks. The rasp marks and attempts to stop the cracks are ineffective because they do not address the cause of the cracks which is the flared foot. Until the flare is removed the feet will continue to crack.	This flared foot has mud packed into the white line and significant separation has occurred. The cracks you can see were the tip of the iceberg for this horse.	A draught horse with good hoof quality but long flared toes which have led to a single crack. Frequently removing the flare and relieving pressure from the base of the crack will restore this foot to normal over time.

Small surface cracks are usually seen in the first 1 - 2 mm of hoof wall running from coronary band to ground surface. They may begin at the top or the ground surface but often begin just below the coronary band and grown downward with the wall. These cracks don't do any serious harm; they are caused by a combination of genetic, dietary and environmental factors. When diet and environment are improved they usually grow out, but some horses have genetically poor quality hooves in both conformation and structure, requiring a high quality diet and regular farriery care to prevent them developing weak, flaking or cracked hooves.

A BALANCED DIET INCLUDES THE NECESSARY VITAMINS, MINERALS, AMINOACIDS, FATTY ACIDS AND ELEMENTS WHICH COMBINE TO PRODUCE STRONG, HEALTHY KERATIN (A PROTEIN) OF WHICH THE HOOF WALL AND SOLE ARE FORMED. FEEDING A TOTALLY BALANCED DIET IS BETTER THAN SUPPLEMENTING ONE MINERAL OR AMINO-ACID. OVER FEEDING SUPPLEMENTS DOES NOT INCREASE RESULTS AS THEY ARE ONLY OF BENEFIT IF THERE IS A DIETARY DEFICIENCY.

Deep cracks and flares

A most important concept of the horse's foot and farriery is that the hoof wall grows as a cone. The cone is smallest at the coronary band and larger at the ground surface. Therefore, the foot has a larger radius the further it is from the coronary band. This is why hooves grow over the shoes despite the fact that they fitted when they were put on. Six weeks later the hoof surface area at the ground is larger than it was when the shoes were fitted. The tiny tubules that make up the hoof wall are the same size at the top as they are at the ground surface. Therefore, as they are basically lifeless tissue they are unable to heal and are most easily pulled apart sideways close to the ground surface. The longer the foot is beyond its maximum length for soundness and hoof balance the more force is tearing the horn tubules apart. To demonstrate this concept take a handful of straws and keep them in your fist all lined up closely and with no spaces between them. Now stand them on a flat surface still bunched closely together and you will notice while holding them that you can place weight on them with your free hand and they will maintain their direction and strength as long as they are bound closely together in alignment. Now let them flare at the base so that they are a teepee shape. As you place weight upon them they will flare outward and easily collapse downward as the straws become further and further apart and the area on the table top they cover becomes bigger and bigger. This is the concept of a flared hoof with hoof cracks ascending from the ground surface towards the coronary band. Flares are the main cause of hoof cracks and are usually due to lack of regular farriery care. Most horses have some conformation faults and it the conformation of the distal limb and foot that determines where the flare will be. Flares usually form on the inside toe for toe-in and the outside toe for toe-out. Flares lead to imbalanced weight-bearing of the wall that exaggerates the flare and leads to hoof cracks. As the wall becomes warped, the horn tubules separate at the weakest point (ground surface). As the wall has no ability to repair itself the crack is forced apart with each step, traveling upward towards the coronary band. Mud, packed into the crack, is forced upward with each stride. This can result in pressure, infection and seedy toe.

Over time a flare usually develops an inward dish in the wall above it. Dishes and flares are usually seen on the same foot. The inward pressure is a result of the outward flare at the base and can result in permanent changes to the shape of the pedal bone. This makes it difficult - if not impossible to regain a normal pattern of hoof growth without flares if the feet are allowed to get too long or are neglected. After all, it was conformation of the foot that predisposed it to developing the flare in the first place. Flares occur on foal feet so start your hoof maintenance early. The best way to manage dishes and flares is to remove the flare from the outside of the hoof with a rasp and then dress the ground surface. This should be done at regular intervals 2 - 4 weekly for foals and 4 - 6 weekly for most adults. Some farriers advise unloading the flared wall and making the area non weight-bearing. I have found this is not always possible or practical even for shod feet. You may find that after you have removed the flared wall from a foot there is only a little heel left to remove and a bevelled edge will finish the trim. Do not shorten the foot from underneath until after the flares have been removed from the front. Otherwise you risk over-shortening the hoof and making the horse uncomfortable.

3 Navicular syndrome/disease (Podotrochlosis/Podotrochlitis).


The classic navicular syndrome shape is a long foot, wider at the toe than the quarter with narrow contracted heels and frog. The hoof wall angle at the quarters is upright and in this case the toe is long and the heels are short and so is the shoe. This is not how to shoe for a good result. This horse was very lame.		This horse has no heels at all! Ideally allowing for some decrease in tension on the deep digital flexor tendon will offer some relief from the pain of navicular syndrome. The low heels will make the problem worse.		After rebuilding some heel with Equithane and dressing the toe from the front of the foot to move the point of breakover back under the leg, shoes were fitted with a graduated heel, a thinned and bevelled toe and greater length under the heels. This horse improved.

It is important to mention that farriery trends vary throughout the world vary and that what is considered normal practice in one country or location may be considered very abnormal in another. For example contacted feet with long, upright heels may be common in Europe where horses are stabled during winter. In Australia most horses live in paddocks until 2 years of age and flat feet and underrun heels are common in many areas. These predisposing factors are due to a combination of genetically inherited foot conformation, breed, overall management, diet, exercise, stabling, frequency of farriery care and the skill of the farrier. Genetic and environmental variety is reflected in the varying causes of navicular syndrome. Farriery, breed and management are significant factors influencing whether a horse does develop navicular syndrome and just like laminitis the risk of a horse developing navicular syndrome is reduced by improved farriery and horse management practices.

A chronic degeneration of the navicular bone in which there is damage to its flexor surface and the overlying flexor tendon in the front feet of the horse. There may be an accompanying navicular bursitis and osteophyte (bony outgrowth) formation. The syndrome is characterised by intermittent lameness (Blood and Studdert, 1999).

Symptoms

It is common for the earliest symptoms of the disease to go unnoticed. The onset is slow and is usually diagnosed only when chronic changes have developed. Seventy percent of horses with confirmed navicular disease have a history of forelimb lameness. This includes shuffling gait and restricted stride for more than 3 month's duration. Pointing the toe is sometimes observed in paddocked or stabled horses. Digging the toes lower than the heels and pillowing bedding under the heels to gain relief can be symptoms in more advanced cases. Early diagnosis is vital for a prolonged, active career. The earlier the diagnosis, the better the chance of treatment providing long-term relief from lameness. The high risk groups are Quarter horses, Thoroughbreds and Warmbloods. The risk to these groups is greatly reduced when all the contributing factors are addressed. Proper equine management is the best preventive measure.

Chronic symptoms

In many cases no classic signs of navicular disease are observed and diagnosis is made when all other avenues for the cause and treatment of poor performance have been exhausted. Degeneration of the navicular bone results in a low-grade ache, particularly when standing about. The lame horse advances the affected hoof to rest it on the toe. If both front hooves are affected, the horse will point them alternately. During exercise the horse often improves once it has warmed up. These horses are usually better when ridden or exercised daily and worse when given time off. Because of pain in the posterior (back) half of the foot the horse tries to minimise pain by avoiding landing on the heel first, as a normal horse does. Navicular horses have a tendency to try to land on the toe, causing a stumbling, shuffling gait that kicks up small puffs of dirt and ultimately causes excessive wear on the toe of the shoe. Alterations to footfall and function lead to a contracted, upright hoof with a recessed frog. The hoof may also have a heavily worn toe in some cases. When turned out to pasture the foot may develop a club foot shape with a concave (dished in) wall at the toe.

Diagnosis

A diagnosis may require modern methods such as nuclear scintigraphy before an approximate area of the distal limb is isolated and a diagnosis is reached. Diagnosis can usually be confirmed by a combination of several of the following techniques: Flexion testing, blocking the nerves which supply the navicular bone, X-rays and palpation of the foot with hoof testers and observation of how the horse moves, how the feet land and of changes to the hoof capsule over time. These factors are combined with assessment of the hoof shape, size and angle, combined with movement and behaviour. one of the best clues is the history from the owner or rider. This gives valuable information and helps when trying to give an accurate diagnosis. Another important point in forming a long term prognosis for the horse owner is the response to treatment. Some horses respond very well to improved shoeing and little other medical treatment is required. Some horses don't respond significantly and medical therapy may form part of the long term management in these cases.

4. Club foot


Before surgery.	After sugery and toe extension with Equitane® and fitting a graduated toe shoe. An exercise program started 3 weeks after surgery. A normal hoof/Pastera angle is achieved over time.

This filly was presented to an equine surgeon for assessment at 18 months of age with a severely clubbed right front foot (broken forward hoof-pastern angle). The foot was short, contracted at the toe, wide at the heels and unable to be extended into a normal position. Therefore, shoeing alone was unlikely to offer any significant improvement over time and her foot was likely to cause her lameness problems and severely limit her future potential as a show or riding horse. The filly was given surgery to cut the check ligament of the deep digital flexor tendon (inferior check ligament desmotomy). Before discharge from hospital, 3 days post surgery it was decided to extend the toe of the clubbed foot with a hoof reconstruction material (Equithane) and to fit a graduated-toe shoe to prevent further toe wear and offer protection. At this time it was noted that an abscess had formed at the toe and the wall was separated. These are common findings in young horses with severely clubbed feet, and further contribute to the abnormal pattern of wear and chronic separation of the white line and dorsal wall (toe). The filly was initially given hand-walking as exercise and this was increased to include gentle lunging at the trot by 3 weeks post surgery. This was continued throughout the recovery period of 4 months. During this time the filly had the shoe removed and refitted at 4 weekly intervals. Improvement in the hoof-pastern angle was noted at each shoeing. It was advised to continue protecting the toe of this foot with either a shoe or tip until at least 6 months post surgery. After this the foot should be allowed to go unshod if possible, as this will maximise heel function and expansion of the foot while the filly is still growing. Regular trimming at monthly intervals is still required. If the toe should begin to shorten and the foot becomes more upright then fitting a shoe or tip will again be required. When I last saw this filly her owners were considering a riding career for her and her future looked much brighter. However, there is a genetic component to this condition and therefore, I would be unable to predict that this filly would, or would not, produce foals that were at risk of developing the same problem.

5. Bar shoe


Injury to the sole or wall can be protected by a bar shoe.	Many modifications can be made to machine or hand made bar shoes	A hospital plate offers maximum protection and access to the sole for treatment when combined with a bar shoe.

Case history: This is a machine made bar shoe that has been shaped to fit this horse's hind foot. The sole is exposed and needs protection and the shoe has been modified to take a hospital plate which is an aluminium plate bolted into the shoe. An old road sign was used to make the plate and the bolts and tapping tool are available from good hardware stores. The shoe is heated and allowed to cool slowly so that it does not become too hard and is then drilled, tapped and the bolts are cut to length and fitted. The plate forms a very strong barrier between the sole and ground surface and offers maximum protection to the sole and pedal bone. The continuous surface of the shoe prevents the sole filling with dirt and bedding and the wound can be covered with medication and dressings and changed frequently if needed. The bolts are undone and the plate lifted during treatment. Silicone sealer around the heels and Elastoplastâ tape around the sole and wall can be used to form an even better seal and keep the injury clean. This type of shoe is used for treatment of penetrating injuries of the sole, after surgery such as resection of infectious osteitis and other traumatic injuries to the sole.

For most injuries and pain in the back half of the hoof, long, underrun heels, corns or injury to the heel or quarter, bar shoes offer protection and a greater weight-bearing platform for the horse to stand on, shifting support further back under the leg, giving an instant improvement in many cases. The shoes offer protection while an area is resected or relieved from pressure due to an injury. A partial version of a bar such as a G, mushroom or V shoe is used to greatest effect for this purpose. After bar shoes are fitted to chronically sore horses they often looks relieved to finally have something under the foot for support. The difference between an egg and straight bar is that the straight bar can move more weight-bearing support onto the frog if desired and does not extend as far under the heels. A straight bar shoe with a small frog clip is often called an English bar shoe. All bar shoes have similar benefits and can be fitted with rolled or set under toes, fullered, plain stamped, concave, deep seated, clipped, side clipped or graduated in thickness from toe to heel, or heel to toe, as required for the individual. Many machine made varieties are available in aluminium or steel and are easily modified. Always address the basic principles of farriery before resorting to bar shoes. Although usually beneficial, bar shoes can also cause excessive frog or heel pressure. This is worse if the heels and frog have not been trimmed correctly and the heels are long and folded under. This will cause lameness in its own right which can easily be confused with the need to fit bar shoes in the first place. Many horses with bar shoes improve once they are removed and shod properly which indicates that all the horse needed in the first place was a balanced, well fitted set of shoes. Bar shoes may force the hoof to land earlier affecting the stride and are often used to improve gait problems. However, bar shoes can also cause gait problems and should be used therapeutically and are not usually recommended for the front feet of horses working at speed. Always remove bar shoes and return to standard shoes when they are no longer required. I avoid bar shoes unless they are strongly indicated for the horses problem and are showing a benefit once fitted.

Egg bar shoes

Egg bar shoes increase the weight-bearing surface and create a larger area of posterior support for the foot and leg, thus moving the center of gravity further backwards supporting underrun heels. Corns, contracted heels, navicular disease, laminitis, heel injuries, and race horses that go "down on the bumpers" may all benefit from these shoes if applied properly. Available in machine made varieties from steel through to aluminium alloys, many farriers hand make bar shoes for the individual horse.