Could your horse have heel pain?

Helen Jacks-Hewett BSc(Hons) PGDip

McTimoney Animal Practitioner & Sports Massage Therapist

Horses evolved to be herd dwelling flight animals and by their nature they do not demonstrate pain in the same way as we humans do. In their original wild environment a horse outwardly showing pain or weakness would be an easy target for predators. Our domesticated horses haven’t changed markedly from their wild counterparts; in fact their genetic makeup is virtually identical. This is a vital factor to consider when evaluating pain in the horse. Just because the horse isn’t outwardly showing pain through lameness doesn’t mean to say they aren’t in pain. The signs of pain are very much more subtle than that and can be difficult to interpret. The range of behavioural changes that could indicate pain is vast and often complicated to understand. However, there may be some physical indicators of pain that could indicate the horse is utilising its coping mechanism to essentially mask a problem.

One such problem receiving plenty of recent attention is heel pain. Heel pain refers to pain in the back portion of the horse’s hoof. It may involve deep osseous structures such as the navicular bone, surrounding soft tissue, or more superficial structures such as the hoof capsule or dermis (Morrison, 2007).

So what are the physical signs of heel pain?

Hoof Deformation

Firstly the most obvious area to examine is the hoof itself. Signs of hoof deformation such as heel contraction and frog weakness can be an indicator the horse has dysfunction in the heel area (Morrison 2007). Normally the frog and heels should have contact with the ground in order to fulfil their role of stimulating circulation and dissipating force (Bowker et.al., 1998). In the shod or damaged hoof this is often impossible and so over time the frog and heels become weaker and more damaged. Raising these structures off the ground even by a ¼” shoe can render them useless. This becomes a vicious circle as the weaker and more contracted the heels and frogs are then the more painful this area becomes and the horse will try and avoid standing on it by taking more weight off the heel and onto the toe. This means there is even less stimulus going through the heel area and even more weakness occurs and so on.

Normal heel ground contact with healthy cartilages. / Abnormal heel ground contact due to ¼” raise from shoe. Heels and cartilages already showing signs of contraction (5 year old horse shod for 2 years).
Normal frog and heel. / Abnormal contracted frog and heel.

Hoof Landing

When moving in a straight line on a flat surface a normal hoof should land slightly heel first or quarters first (Chateau et al., 2004). Like every ungulate a heel first landing is required in order to engage all of the correct muscles involved in prolusion and move the entire body over the ground. Landing flat footedly or toe first creates a shorter stride and reduces the forward momentum. This means that landing with the heel first is the most efficient stride pattern. When a horse is suffering from heel pain it will try to land flat footedly or toe first to avoid weight bearing in the back portion of the hoof. This is why horses with heel pain often find it difficult to walk downhill because they have no option but to put weight on their heels, and walking uphill is easier because the toes are bearing more weight. Toe first landings are a big warning sign that something is wrong and may often appear before the signs of hoof deformation.

Normal hoof landing. / Toe first heel pain landing.

Posture

In a comfortable horse the lower legs should exit the body in a straight line down to the ground – the phrase ‘a leg at each corner’ can be applied. The structure of the horse’s legs comprises of columns of bones stacked one on top of each other with muscles and tendons at the front and the back of each limb working equally to hold the leg straight in ‘neutral’ position. This is also known as the ‘stay apparatus’ and is thought to be an evolutionary advantage that allows horses to sleep for periods of time standing up. The horse with heel pain will stand in a way to alleviate pain in the heel region by adopting a continual forward lean to put more weight on the toes and less on the heels. The hind legs are placed further forward under the body to take more of the weight off the front end and often the horse looks like it’s ‘a circus elephant on a box’. This continual forward lean creates problems for the stay apparatus by interfering with the equal balance of the muscles at the front and back of the legs, which necessitates extra muscular effort. The muscles normally involved in retraction of the forelimb are working overtime causing them to overdevelop, become fibrotic, contracted, fatigued and sore. Horses with heel pain often appear to have croup high conformation because the continual forward lean lowers the forehand.

It’s not just the forelimbs that are involved, secondary hind quarter problems occur from front heel pain due to the horse shifting greater amounts of weight onto their hindquarters. Over time the hind feet develop abnormal hoof angles and low heels because of the unnatural stance and loading. In some cases this can lead to ground parallel or counter rotated pedal bones due to collapsed heels. These reversed hoof angles in the hind feet may lead to patellar, hock and stifle problems, and lumbo- sacral pain. What originally started as heel pain in the front feet migrates into a whole body problem. In some cases the first problem an owner notices is the horse showing signs of back or girth pain by being reluctant to be saddled or mounted.

Normal posture. / Heel pain posture.

Summary

The horse doesn’t have to show signs of lameness in order for it to have heel pain. Often the physical signs of heel pain in the shape of the hoof, the hoof landing and the posture are obvious long before the commencement of clinical lameness. These should be considered to be warning signs that something is amiss and needs to be investigated to prevent further or long-term damage.

Bowker, R., Van Wulfen, K., Springer, S., and Linder, K. Functional anatomy of the cartilage of the distal phalanx and digital cushion in the equine foot and haemodynamic flow hypothesis of energy dissipation. Am J Vet Res 1998; 59 pp961-968.

Chateau, H., Degueurce, C.,and Denoix, J.M. Evaluation of three dimensional kinematics of the distal portion of the forelimb in horses walking in a straight line. Am J Vet Res 2004 65 pp447-455.

Morrison, S. Practical approaches to heel pain. 10th Geneva Congress of Equine Medicine and Surgery 2007.pp201-203