Managing Lower Limb Conformation From a Hoof Perspective with Dr. Luke Wells-Smith

After examining 1000’s of horses in different life stages, breeds and disciplines, it has become evident that the ‘perfect’ conformation doesn’t necessarily exist. If managed correctly, many horses can perform at a high level in different disciplines despite some significant lower limb variations. In nature, generally speaking, symmetry is hard to find. This is true when examining the horse and limb conformation. The important part of examining and identifying different limb conformations is how that relates to the hoof, particularly how it grows and loads. This article aims to discuss a number of different conformations and how we can manage them in the adult horse. To do this I’ll break the discussion into two basic angular limb conformations - toe in and toe out. At the end, I’ll discuss the relationship between angular and flexural conformations.

Angular Limb Conformations

Toe in conformation

Toe in conformation basically means the toe/hoof points, in some degree towards the opposite limb. This can range from mild to severe and can occur in one limb or both. Toe in conformation is common in a number of different breeds, in particular Warmbloods, Thoroughbreds, Arabs, Western Breeds (Quarter Horses and Paint Horses). It appears to be less common, but still evident in ponies and large breed horses such as Clydesdales.

In general, one limb is worse than the other. The conformation is typically caused by changes to the growth plate above the fetlock when the horse is young and growing. In some cases a toe in conformation can be exacerbated by an offset knee conformation - where the top of the cannon bone is shifted towards the outside of the knee. 

In mild cases, the foot may actually hit the ground in line with the rest of the limb, however when the limb is in the flight phase of the stride, the hoof may come in. In severe cases, when the limb is fully loaded, the hoof may almost interfere with the opposite limb. 

Because of the toe in conformation, the hoof is loaded asymmetrically. The outer wall, particularly the heel and quarter hits the ground first. If the horse is barefoot, the outside wall typically wears excessively, causing the inside wall to become long and flare. The same occurs when the horse is shod, however it is less obvious. To trim this hoof conformation, we need to understand that creating equal inside and outside wall lengths is very important. Because the outer wall either wears faster or grows less, it doesn’t need to be trimmed. In comparison, the inside wall does need to be trimmed. That will start to help establish symmetry from the inside and outside hoof walls. This helps to improve the loading pattern of the limb and joints, in particular the coffin and pastern joints. 

Toe out conformation

As you can imagine, toe out conformation is the opposite to the toe in conformation. This means that the limb rotates away from the opposite limb. Toe out conformation is found in all breeds of horses, however is common in ponies and narrow-chested larger breed horses. Again, toe out conformation can vary from mild to severe. 

Toe out conformation is typically associated with multiple factors. It is rarely caused by the growth plate above the fetlock, like with the toe in conformation (although it can look like it is). It is sometimes associated with the growth plate above the knee, causing a knocked knee appearance. The most common reason is due to a narrow chest which causes the elbow to adduct (move closer to the body) and then results in the limb to be rotated out.

Once again, because of the limb variation, the hoof is asymmetrically loaded. Instead of the outside wall hitting the ground first, it tends to be the inside heel. Racehorses with a toe out conformation tend to have inside heel pain and a shunted coronary band on the inside heel. Again, this asymmetrical loading changes the growth pattern of the hoof. The outside wall grows faster than the inside wall and needs to be trimmed accordingly.

Link Between Angular and Flexural Conformations

Interestingly, there appears to be a link with the toe in / toe out conformations and flexural conformations. Flexural conformation relates to the tension on the flexor tendons that dictate how the hoof grows. The typical example is a club foot or a hoof with an upright heel. This is caused by an increase in tension through the flexor tendons, causing the heels to be unloaded and hence they grow faster and at a different angle. 

The opposite is the low heel or flat foot. This is caused by a relative laxity in the flexor tendons, resulting in increased load in the back part of the foot. This causes a reduction in heel growth and a change in heel angle.

Now, an upright heel/club foot conformation appears to be associated with a toe out conformation. A low heel/flat foot appears to be associated with a toe in conformation. Because of this relationship, it dictates how the foot needs to be trimmed and shod. Below are two examples:

Upright heel and toe out conformation:
* Grows more heel height than toe length 
* Grows more outside wall than inside wall
* This means that at the end of the trimming/shoeing cycle, the heels are trimmed and potentially the outside wall, leaving the toe and inside wall

Low heel and toe in conformation:
* Grows more toe than heel height
* Grows more inside wall than outside wall
* This means that at the end of the trimming/shoeing cycle, the toe is trimmed and potentially the inside wall, leaving the heels and outside wall

Depending on the degree of angular limb variation, heartbars can be helpful in establishing even loading through the back part of the foot. This can also help with the growth patterns associated with these types of lower limb conformations. 

When we start to identify these different conformations, we can begin to improve both joint and hoof health, increasing the longevity of soundness in our equine partners.

Luke is a veterinary podiatrist providing a high level of service to the Australasian horse industry through affiliated veterinary practices and an online consultancy portal. Luke is the founder of Motion Equine Podiatry Consulting and is available by appointment in multiple locations along the east coast of Australia.
luke.wellssmith@gmail.com | www.motionepc.com.au

Sign up to our newsletter