Content

1. What is navicular?
2. Recognising the signs
3. Understanding the causes
4. The natural function of the DDFT
5. The chain reaction of degeneration
6. Management and recovery
7. There is Hope ... introducing Rockley Farm
8. Conclusion

When your horse is diagnosed with navicular syndrome, it’s natural to feel overwhelmed and uncertain about the future, and more importantly, how to best care for your horse. There is hope though; with early intervention and correct hoof care, many horses can continue to lead happy, healthy lives, and importantly, be sound throughout.

What is ‘navicular’?

Navicular syndrome describes a condition where pain arises from the navicular bone in the foot and the surrounding soft tissue structures. It’s a common cause of forelimb lameness in horses and can result from poor foot conformation, especially long toes and low heels. This conformation places extra biomechanical strain on the heel area, predisposing the horse to developing what’s termed 'navicular disease' by vets. Rest assured this is no 'disease'; it's a syndrome - cause, effect, damage, symptoms, which I'll explain as we go.

The navicular bone sits roughly in the centre of the hoof, behind the pedal (coffin) bone, and is held in place by several small ligaments. This small bone is there for a very important reason, and here’s where the root of the whole navicular syndrome lies. It's to help keep the deep digital flexor tendon (DDFT) run smoothly down the back of the foot onto the pedal bone. A small sac of fluid, the navicular bursa, sits between the navicular bone and the tendon, and acts as a cushion where the DDFT passes over the bone.

Stressors can damage these structures which leads to what’s commonly known as ‘navicular’, but the reality is that this syndrome lies at the root of a malfunctioning DDFT, and not the navicular bone itself - this is merely a symptom. And the cause? Metal shoes preventing the natural biomechanical movement of the hoof. Cause and effect. Now to the symptoms.

Recognising the signs

Navicular syndrome can cause lameness ranging from mild to severe, but it’s important to remember that not all cases are the same. This lameness is usually most obvious when the horse is trotted in a circle on firm ground. The severity depends on how severe the damage is.

Typically, both front feet are affected, sometimes with one foot worse than the other. Any horse of any age can be affected, and if left untreated will developing to chronic lameness, but acute injuries can also occur in some cases. It's rarely seen in the hind feet and in ponies.

Understanding the causes

The highly respected Dr Bowker, a former professor at Michigan State University’s College of Veterinary Medicine, has spent years researching the root causes of navicular syndrome, and has identified beyond question that improper trimming and shoeing leads to early damage in the back of a horse’s feet. This area, including the frog and digital cushion, is crucial for protecting the navicular bone and maintaining overall hoof health.

Traditionally, navicular syndrome is diagnosed when a horse shows lameness in both front limbs, confirmed by nerve blocks and X-rays. However, Dr Bowker suggests that the damage begins much earlier, and can occur long before it’s visible on radiographs. Here's the crux of it all.

The natural function of the DDFT 

If a horse is allowed to walk on its own four feet naturally, every step is very different from that of a shod hoof. Specifically, the whole base of the hoof, i.e. the bottom of the peripheral hoof wall, the sole, the frog, the heels, and the fascia, nerves, and blood vessels within the frog and digital cushion, all take the impact of the landing, instead of only the 'raised' peripheral wall in a shod hoof.
 
Crucially though, a hoof naturally lands heel-first compared to a toe-first landing in a shod hoof. (For hoof nerds, watching a natural unshod hoof landing is a thing of beauty 😉).

This natural heel-first landing is vital because it enables three key mechanical functions:

• Frog impact absorption: The heel-first landing allows the frog to absorb the impact effectively.
• Frog stimulation and blood circulation: The stimulation of the frog compresses the digital cushion above it, acting as a pump to push blood through the hoof corium and back up the leg. Without this stimulation, the hoof’s blood supply diminishes, leading to poor hoof health and integrity.
• DDFT functionality: The DDFT flexes (stretches) as the toe flicks up, allowing the heel to land first. As the toe then flattens to the ground surface, the DDFT returns to its regular alignment, preparing for the next step. This cycle ensures healthy blood flow and optimal hoof function.

This natural movement and the DDFT's role are significantly hindered when a horse is shod. Here’s how:

• Weight distribution: A shod hoof bears weight only on the periphery, unlike the natural distribution across the entire hoof base.
• Frog redundancy: The frog becomes inactive, leading to diminished shock absorption and a crucial healthy blood flow through the hoof.
• Toe-first landing instead of heel-first: A shod hoof lands toe-first, causing the DDFT to shrink and become less flexible, increasing the risk of injury.
• Blood flow and hoof health: Studies show a significant loss of blood flow in shod hooves, affecting not only the hoof but the entire limb.
• Proprioception: Reduced blood flow also impacts the horse’s ability to feel their feet, leading to stumbling and injuries. (This was our Kelso, with me usually ending up on his neck and him with cut bruised knees).

Understanding these differences highlights the importance of allowing horses to walk naturally, ensuring their hooves and overall health remain in optimal condition.

The chain reaction of degeneration

Dr Bowker’s studies reveal that the degeneration begins in the caudal (rear) part of the foot, then spreads. This means the frog and digital cushion may show signs of wear and tear, which can then affect other areas, eventually involving the navicular apparatus.

One of the most alarming findings is that the coffin (pedal) bone can start to change shape and elongate at a very young age. This is often due to trimming techniques that allow the hoof wall at the toes to grow too long, causing the frog and digital cushion to atrophy.

Trimming practices have a profound effect on the hoof’s structure. When the hoof wall at the toe gets too long, it changes the way the horse’s foot bears weight and absorbs shock. This can lead to a broken-back hoof-pastern axis, where the pastern is more upright than the toe, and other structural issues.

Management and recovery

With correct hoof care, we can prevent and even reverse some of the damage. Here are some key steps to consider:

1. Keep the toes short: Regular trimming to keep the toes short and the heels back is crucial. This helps maintain a healthy foot structure.
2. Minimal trimming of the sole and frog: Avoid over-trimming these areas. The frog in particular should be left to perform its natural function.
3. Frequent trimming: During warmer months, when hoof growth is faster, aim for more frequent trimmings, i.e. every 3-5 weeks.
4. Support: Daily anti-inflammatory support plays a vital role in both comfort and stress from the pain. See our Pain shop page for pain/anti-inflammatory support.

Key factors for long-term soundness

Dr Bowker highlights several factors that contribute to a horse’s long-term soundness.

• Get those shoes off! (Even if it’s just short term). The most important aspect of treatment is corrective trimming to reduce the pressure on the heel area.
• Short toes: This lessens structural imbalances by reducing the toe length to help with 'breakover', the point in the stride when the heel leaves the ground and the foot rotates over the toe.
• Healthy frog: An active frog supports overall hoof function and enhances a healthy blood flow through the hoof, the digital cushion (which pushes the blood flow back up the leg), and surrounding tissues.
• Dense coffin bone: Strong bones are less susceptible to degeneration.
• Thick lateral cartilages: These provide additional support and cushioning.
• Hooves need minerals! Why? Simple. Our UK soils are nutrient-deficient which means the grass that grows in it will be as well. And when I say nutrients, I mean key nutrients for hoof health - specifically the essential EFA omega-3, quality protein by way of amino acids methionine and lysine, as well as critical key minerals - magnesium, phosphorus, copper and zinc. Without a mineral supplement balanced to our UK forage, you won't achieve strong, robust hooves. These vital nutrients put back what’s missing in our UK forage into our horse’s diet, and you'll find them all balanced to the correct ratios, and in their natural form, in our EquiVita/VitaComplete mineral balancers.

There is Hope

Have you heard of Rockley Farm? If not, let me introduce you to Nic Barker who runs Rockley. Rockley is a small hill farm in the Exmoor National Park specialising in barefoot rehabilitation livery for horses with hoof-related lameness.
 
I first came across Nic and Rockley around mid-2006, when I was desperately searching for anything to help our Kelso’s crumbling (shod) hooves. Thanks to Nic’s subsequent forum for owners trying to understand and manage the condition, it was clear that the root of the navicular syndrome was actually a damaged, malfunctioning DDFT, and not the blanket term of ‘navicular’ used by vets, with the cause being metal shoes preventing the natural biomechanical movement that the hoof should follow naturally.

Back then, the misunderstood 'navicular' term was so prevalent that it was almost considered an epidemic. And no surprise, because as new research was published, we started learning that:

1. For every 1-centimeter of extra toe length, there is an extra 50-kilograms of force acting on the tendons.
2. For every 1-degree drop in sole angle where the DDFT inserts into the coffin bone (affected by palmar angle), there is a 4% increase in the pressure exerted by the DDFT on the navicular bone. (Credit Dr Renate Weller)

The solution? Shoes were removed, the hoof trimmed correctly, and the horses were allowed to walk on their own four feet and come sound naturally, on comformable surfaces and gentle, appropriate rehab and retraining.

Most horses that ended up at Rockley were in Last-Chance-Lameness-Corral, with MRI's showing DDFT, collateral ligament, or navicular bone injuries. Their vets had given up on them, so they were either retired off as a pasture pet or worse, given a PTS prognosis. Almost two decades later, there's now a much better understanding of the underlying issues, and many horses are now thriving due to the correct approaches being taken.

There’s more good news. Most insurers now cover a Rockley rehab, but back in the mid-2000s they didn't. Owners had to front up the cash, but it was worth every penny, with an incredible 80%-plus of horses returning to the same level of work – if not greater – than before. If you explore the Rockley Farm website, you'll see a gallery of amazing Rockley Rehabs still competing at a high level.

But first, have a quick look at this YouTube video of Rockley-recovered barefoot hooves in action on a sharp stony surface. Just 7-minutes long, this video will show you real-life slow-motion Rockley rehabs in action. It truly makes for eye-opening viewing, and I promise you your jaw will hit the floor.

These same horses were all previously in that same last-chance corral, having those very same lameness syndromes where the vets were no longer able to help them with many of their owners advised to have their horse PTS. This is real evidence that for any horse who may be in that corral, getting those shoes off and conditioning their hooves as performance barefoot hooves - even short-term - can produce remarkable results.

If your horse has been diagnosed with either navicular, DDFT, collateral/impar ligament damage, etc., Rockley is your go-to resource for how to help your horse get better. Nothing will inspire and assure you more that there's always hope, and that there is another way.

Conclusion

Receiving a navicular diagnosis for your horse can be daunting, but understanding its causes and taking proactive steps can make a significant difference. It’s important to stay hopeful—the Rockley website is proven evidence. By following Dr Bowker’s advice on proper hoof care, you can help your horse maintain healthier hooves and potentially reverse some of the early damage.

Prevention starts with correct trimming practices and regular hoof maintenance. Your horse’s feet will thank you, and together, you can navigate the ‘navicular’ journey with confidence and care.