What is navicular syndrome?
While many know it as navicular syndrome or disease, the full term for this condition is podotrochlear syndrome. It is now known that the origins of this disease are multiple but not always well known. What is certain is that the pain linked to this syndrome comes from lesions of one or several structures composing the podo-trochlear apparatus, namely
- The navicular bone (or distal sesamoid bone). This is the bone located between the 2nd and 3rd phalanges. When it is affected, it can be a fracture, osteolysis ( the breakdown of useful bone) or osteophyte ( the formation of useless bone), sclerosis (thickening of the bone)...
- The podo-trochlear bursa. This is a fluid-filled "pocket" that is located between the navicular bone and the deep flexor tendon of the finger. When it is affected, it is usually an inflammation called bursitis
- The deep flexor tendon of the finger. It slides over the navicular bone using the podo-trochlear bursa to limit friction
- Ligaments that connect the bones together: navicular and phalanges When they are affected, it is generally a question of inflammation
What are the symptoms of navicular syndrome?
Generally, horses with navicular syndrome are only affected in the front legs. The syndrome can affect both front legs or just one.
The posture of horses with navicular syndrome is fairly "classic".
- At rest, the horse usually puts the affected foreleg forward to relieve the pain. In the long term, changes in the structure of the affected feet may also occur, with them becoming narrower and more upright, known as atrophy.
- During exercise, the horse limps more or less depending on the pain. Gaits are often cramped and shortened. The lameness is usually aggravated if the horse is worked in a circle. If the navicular bone is affected, the lameness will be more pronounced on hard ground, whereas if it is the ligaments that are affected, the lameness will be more pronounced on deep ground.
What is the diagnosis for navicular syndrome?
The best way to confirm that your horse has navicular syndrome is to have an examination with your vet. He or she will be able to confirm whether the pain seems to be caused by navicular syndrome. To do this, the vet will perform two types of examination:
- Static (at rest): In addition to looking at the horse's position and whether its feet are in the right shape, the vet can perform the plank test. This involves putting the horse's foot on a board and holding the other limb up. The vet will then lift the board to put tension on the foot and especially the whole podo-trochlear apparatus. The next step is to observe the horse's reactions to pain (agitation of the neck, jumping off the board, etc.). This is not an easy examination with fairly young or stressed horses. This is why the diagnosis must be confirmed with the following examination.
- Dynamic (in motion): In this case, the aim is to watch the horse move and see if its gaits are cramped. The soft ground and hard ground examination can also help to locate the affected area.
Once both examinations have been carried out, your vet will probably take x-rays to look at the navicular bone and an ultrasound scan to look at the soft tissue. He or she may also suggest an MRI (Magnetic Resonance Imaging) which allows a complete examination of the area.
What is the treatment for navicular syndrome?
As with osteoarthritis, navicular syndrome is a degenerative condition that worsens over time. It is therefore not possible to cure navicular syndrome. However, there are treatments that will be adapted according to the pain, the structures affected and the work required of the horse.
- Medical treatment : Depending on your horse's condition, your veterinarian may suggest different medical treatments. Some treatments will be general, such as the use of non-steroidal anti-inflammatory drugs used to reduce pain. By general route, biphosphonates are a treatment that acts on the bone to prevent its deterioration and thus limit bone remodelling. More local treatments such as corticosteroid infiltrations will act on the pain but will not have a direct action on the bone.
- Environmental treatment : When lameness is too severe, the horse should be rested to reduce soft tissue inflation and/or bone remodelling. Regular monitoring by your farrier or groom is also essential to minimise the stresses that can be placed on the podiatric system.
- Food supplements : In addition to drug treatments, food supplements can be used to provide elements to support the treatment of navicular syndrome. The action of food supplements varies according to their composition. Some will help to limit stiffness and improve the flexibility of the stride, for example supplements based on harpagophytum. It is also essential that the horse's feet are in good health, so don't hesitate to provide elements that support good horn growth, such as biotin.
Managing a navicular horse on a daily basis
If your horse's career is not totally compromised when he has navicular syndrome, it is important to make some adjustments:
- Where possible, it is important to keep the work for your horse light to limit the impact on its joints, feet...
- Work your horse on soft ground (neither too hard nor too soft) and don't neglect your relaxation which allows to "warm up" the foot at the beginning of the work.
- Limit tight curves and work in a straight line
- The use of crampons should be avoided as they block the foot
- Keep an eye on the inch of the feet and have the hooves regularly maintained by your farrier or groom. Poorly maintained or overly long feet can make your horse's pain worse.
- Monitor his diet, as for all pathologies affecting the limbs, it is important to avoid excess weight as much as possible, so adapt your horse's diet to his needs (age, breed, work...)
Navicular syndrome is a complex condition that will considerably alter your horse's daily life. For its well-being, the follow-up of your veterinarian and your groom/marcher is essential.
If your horse is showing symptoms that could be consistent with navicular syndrome, call your vet who can make a rapid diagnosis and provide quick relief for your horse.
If you have any questions about navicular syndrome please feel free to ask us on our social networks.