Too much, too young: Splints

By Sally White

Many years ago, I used to run a lot. I pounded the streets for seven or eight miles at a time, convinced I was getting myself fit, but in fact I was slowly but surely jarring and bruising my shin bones until in the end they started, literally, cracking up with a stress fracture. It was sheer agony, and ironically ended up in my taking so much time off exercising that I was as unfit as I had been to begin with.

Why am I telling you this? Because something very similar can happen to young horses. The effect of long, hard training on bones which are still forming is similar to miles of jogging on hard surfaces, and young legs just can’t cope. Splints, as they are known, are the most common cause of lameness in young horses, and usually happen when the horse begins serious work.

What are splints?

The problem can arise on both forelimbs and hindlimbs. The splint bones flank each side of the cannon bones, and are long, thin, slightly curved bones which taper down towards the fetlock and end a little way above. They are attached to the cannon bones by very flexible ligaments in young horses, but as the horse grows older become unified with the bone.

Splints form when the tissue which lines the splint bones becomes damaged and inflamed. The body reacts by producing new bone to compensate, usually rougher and less dense than the original bone. There is also further swelling and pain around the formation of this bony lump. Eventually the new bone becomes visible under the skin of the leg, in a lump known as a splint. This lump, once it has formed, may change shape and become smoother, but it is permanent.

Splint bones can also fracture – much as my own shin bones did! – but this causes a widespread swelling and the horse is more lame, for a longer period.

Splints form in three ways, known as true, false and blind splints.

A true splint is when the ligament between the splint bone and cannon bone tears. The swelling will appear on the groove between the splint and cannon bones.

A false splint is caused by concussion or other trauma to the cannon bone, and is seen on the outside surface of the splint bone. This kind is usually caused by kicks.

A blind splint occurs on the inside surface of the splint bone, and is very difficult to detect as there is no outward swelling as there is with other splints.

Why do young horses get splints?

Young horses are the most susceptible to splints, particularly when they start training. The more intense the training is, the more vulnerable a young horse is to splints. Hard ground can also be a problem, as young legs are particularly prone to concussion.

Overfeeding also contributes to the process. Overweight youngsters, who are fed more hard rations than they need for the work they are doing, will have weaker bones which are under more strain than a horse fed in balance with the demands made on him. Imbalances in dietary calcium and phosphorus are particularly dangerous. Most feed manufacturers can give a detailed, tailored diet suitable for an individual horse, and unless you are extremely proficient at judging your horse’s dietary needs, it is well worth talking to their qualified nutritionists.

Bad or neglected shoeing and hoof care can also cause splint formation by putting the foot out of balance and placing stresses and strains on the lower legs.

You may also find that a young horse with certain problems in his conformation will get splints more easily. These faults include bandy legs, toed-out feet or top-heavy horses. The reasons are much the same as for all splints – an out-of-balance horse will put more strain on his legs.

And finally, splints can also be caused by kicks to the lower limbs from other horses. This is the most likely cause if you have ruled out all of the above, and, most tellingly, if there is any evidence of a wound near the area of the swelling.

How do I know my horse has a splint?

The first sign is usually when your horse goes moderately and persistently lame, most visibly at the trot and on hard ground, or when the horse is circled.

Splints can appear as a swelling anywhere along the splint bone, on the front or back legs. However, they are most commonly found on the inside of the leg, usually the foreleg (which normally bears more weight in exercise) and on the upper third of the splint bone (nearest the knee). The swelling will usually be hot and the horse will show signs of pain if you touch it.

What should I do if my horse develops splints?

The first thing to do if you suspect your horse has splints is to call the vet; the second thing to do is to stop working the horse in any way at all.

Your vet may use x-rays to confirm the diagnosis and find out how bad the damage is. The x-ray will tell you if the splint bone has fractured, and will also tell you if the damage extends up into the knee area (sometimes known as a “knee splint”), or affects the ligament running up the back of the leg. Both of these are rare, but they are serious complications, and your horse’s chances of making a full recovery will be reduced.

Further diagnosis can be made using ultrasound, which will tell you if the splint is affecting other soft tissues in the leg. Finally, a nerve block may be necessary, especially where a blind splint is suspected, to determine exactly where the lameness is located. Nerve blocks work on a system of elimination. They involve systematically numbing all areas of the leg except one, and then trotting up the horse; if the horse goes sound, the area of the leg which has been left unblocked can be ruled out as the area where the lameness is located.

A splint will require complete rest for your horse. He should be put on box rest, with some short walking in hand when the worst of the pain and swelling subsides. If the horse is not given a complete or long enough break from work, the splint may persist, becoming larger and more painful.

Your vet will probably prescribe anti-inflammatory drugs, and you will need to cold-hose the area for 15 minutes, twice a day. Support bandaging will also be helpful. Stable bandages need to be applied over a padding, such as gamgee, to eliminate any pressure points, and it is also a good idea to bandage both legs (either forelimbs or hindlimbs) so that the unaffected limb doesn’t bear a disproportionate amount of weight and suffer muscle damage.

For really serious cases, or if the splint is affecting the ligament at the back of the leg or the knee, surgery may be necessary to remove the bony growth. This may also be an option if your horse is used for showing, in which case a permanent splint would be undesirable and would limit his prospects.

Horses usually get over splints with nothing but an unsightly lump to show for it, and given the above treatment and enough rest time, will recover soundness and go on to start work again. But, if the splint has been caused by conformational problems, he may be unable to recover. Some conformation faults can be corrected, by remedial shoeing, for example. Should the conformation problem be a permanent one, the horse which develops splints because of it is likely to suffer from lameness for the rest of his life, and will probably be unfit for any kind of ridden work.

How can I make sure my horse doesn’t get splints?

The best cure for splints is, without doubt, prevention, and there are a number of things which the owners of young horses can do to protect them from harm:

• always wait until your horse is old enough before you ride him (see my previous article, The Great Age Debate)
• never work your horse too hard, too fast or on ground which is too hard
• consult a nutritionist to make sure you are feeding your horse a balanced diet which is suitable for his age, condition and work
• take action to correct any minor conformation problems early, in consultation with your vet and blacksmith.

• if you suspect your horse is starting to form splints, rest him well and long to prevent the condition from worsening

It is worth remembering that no horse has ever suffered from not working enough, so long as his diet is right. A little caution at this delicate stage in your horse’s life can pay dividends in ensuring that he stays sound, happy, pain-free and unblemished for a long and productive working life.

Article courtesy of Suite101.com.