Category: Clinical Directors

Joint pain can be mild to severe; even mild joint pain that is unnoticeable in terms of lameness to the rider can be performance limiting. A sore joint may stop a show jumper landing on the correct lead after the fence or it may cause the horse to roll unnecessary poles of higher fences. A dressage horse may show asymmetry of limb action during complex dressage movements. Polo ponies may find it difficult to stop and turn sharply and race horses with joint pain may be slower than their expected potential. Joint pain is as a result of joint inflammation, so left untreated some inflamed joints will settle down with rest. Some chronically inflamed joints go on to become osteoarthritic. Early identification of joint inflammation and appropriate treatment can reduce the chances of chronic joint pain and therefore poor performance and lameness issues.

 

Often riders will call and say they think there is a problem with a horse, and I now look at higher level competition horses on a regular basis to monitor for joint pain. The first thing is to ask the rider to describe the problems they think they are having. I then palpate the horse’s limbs for obvious filling of the joints, as in most cases an inflamed joint will have an effusion, which is where the inflamed lining of the joint produces an excess amount of fluid. Some effused joints can be identified by visual inspection as the joint bulges. In some instances, particularly with the fetlock joint, it is possible to feel a palpable thickening of the joint capsule. Some joints will feel warm to the touch.

 

The next step is to trot the horse up on a firm flat surface and see how it moves. One of the advantages of regular checks is the vet gets to know what it normal for the horse and is then able to spot subtle gait changes. Flexion tests are a valuable way of identifying a problem with a joint, most inflamed joints will result in lameness after flexion test. The horse will then be evaluated under saddle, on the lunge in a school and on a hard surface. The rider will be asked to demonstrate the problems they are having, this may be during complex dressage movements or jumping obstacles.

 

Often it is possible to identify a specific joint causing the problem by clinical examination, but a lot of the time it is necessary to anaesthetise or block sequentially joints on the limb in question. Once a joint is blocked the horse is put back in the situation that demonstrated the lameness the best, i.e. on the lunge, on the hard or flexion test. Often there is little for the vet to visually see and the response to blocking must be assessed by the rider.

Laminitis is a painful condition involving inflammation of the laminae. In severe cases the laminae become inflamed all around the hoof resulting in uniform separation, when the limb is loaded the whole pedal  bone then ‘sinks’ within the hoof. The prognosis following rotation is much worse; radiographs are useful to identify what had actually happened.

Causes

There are several reasons why laminitis occurs and it is important to identify the cause so treatment can be carried out accordingly;

1. Equine metabolic syndrome (EMS) which is effectively a form of insulin resistance.
2. Cushing’s disease which many older horses and ponies are now diagnosed with.
3. Some form of sepsis or infection that result in the release of toxins within the body, such as colitis, colic surgery or retention of a portion of the placenta after foaling. Grain overload also falls into this category as the change in diet results in abnormal toxin producing bacteria colonising the gut.
4. Excessive loading of one limb due to injury to the opposite limb. 
5. Excessive exercise on hard ground.

Clinical Signs

Laminitis affects the front limbs more commonly that the back limbs, but one foot can be affected or even just the hind feet. The typical signs of laminitis include;

1. Abnormal stance – usually with the weight rocked back onto the heels and toes out in front off-loading the weight from the more painful toe region.
2. Often cases look very awkward on their hindlimbs, but this is a result of more load being taken by the back end.
3. Walk is reluctant with a toe slapping gait, where the heel is loaded before the toe. There will often be stiff, stilted gait when turning sharply on a hard surface.
4. Often soft footing will be favoured by the patient. Severe cases will lie down and be reluctant to get up.
5. From a clinical point of view the hoof capsule may be hot with a strong pulse palpable in the palmar digital arteries at the back of the fetlock and there will be a pain response on hoof tester pressure in the toe region.

If laminitis is suspected, the first thing to do is make sure there is a deep soft bed, administer pain killers in the form of phenylbutazone if available and then contact a vet for assistance. Laminitis is in many cases an emergency.

Treatment

This will comprise of the following:

1. Removal of shoes, shortening the toe to reduce the rotating effect of the deep digital flexor tendon.
2. Some form of frog support will then need to be applied, and this is to off load the weight from the painful hoof wall. 
3. If we know there has been a toxic episode then icing the feet can reduce the blood supply and prevent further toxins from reaching and damaging the laminae further.
4. Over the years many products have been tried to affect blood flow to the laminae, such as ACP and an ointment form of trinitroglycerine.
5. Phenylbutazone or a derivative is the main pain relief used.
6. Appropriate levels of exercise depending on response to therapy, initially strict rest, then more comfortable turn out in a small paddock may be allowed.
7. Once the initial laminitic incident is under control, then there are a multitude of types of shoes that can be applied to the feet from egg and heart bar shoes, reverse shoes, four point shoes with rails to clogs. The clogs have saved many horses’ lives recently and again are my favoured transition from strap on pads to more normal shoes.