Navicular Syndrome #2
Last week we began to discuss Navicular Syndrome. We learned that Navicular is a syndrome that may involve many different structures in the heel region of a horse, most commonly in the forelimbs. We discussed the anatomy, history, clinical signs, the possible disease processes, and contributing factors. This week’s article is going to focus on the diagnosis, treatment, prevention and prognosis of horses with Navicular Syndrome.
Diagnosis of this condition is done through a complete physical and lameness exam. The veterinarian will have Navicular in mind as a potential differential diagnosis for the lameness given the appropriate (or variation of the appropriate) history and clinical signs. The pain will be localized to the heel region of one or two forelimbs. This is done with the aid of flexion test and hoof testers. The pain will most likely be minimized or eliminated after local anesthesia is administered. At Twin Valley VHS, we recommend freezing only the more severely affected leg with a palmar digital nerve block. This is done to allow the horse to demonstrate to us that the other leg is also painful. The lameness exam will also assist in ruling out other potential causes of lameness. Radiographs (x-rays) are often recommended to look for degree of bone and articular change. They also help to rule out other potential problems and give a prognosis.
Treatment of Navicular Syndrome is complex and most often lifelong. The first step in treating navicular horses is to correct any conformation problems that can be fixed and provide the horse with rest until the feet are at a more ideal angle. This is done through corrective trimming and shoeing by a qualified farrier. The goal of corrective shoeing is to reestablish a normal foot to pastern axis and provide balance to the heels. These horses often need their toes shortened drastically and heels elevated to allow them to stand up right. The toe of the shoe is rounded or rolled to hasten the break over point and therefore minimizing the strain on the deep digital flexor tendon (DDFT). Other corrective shoeing procedures may involve egg-bar shoes, digital support pads and wedged pads.
Navicular Syndrome is a painful disease that results in arthritic changes of the associated joints. Therefore, one of our treatment plans is to treat navicular horses with nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs are used for their pain relief and anti-inflammatory properties. They can also help prevent clot development that may be contributing to the disease process. At Twin Valley VHS, Phenylbutazone (Bute) is the anti-inflammatory of choice for Navicular. Many horses with Navicular Syndrome require intra-articular (injected into the joint space) steroids and hyaluronic acid (HA). These joint injections are done to slow down the arthritic change associated with Navicular. Many horses are also treated with Adequan or Legend to promote joint health.
Surgical options can be considered in horses that are nonresponsive to medical treatment or whose disease is too advanced for medical therapies. At Twin Valley VHS, we can perform a surgery called Palmar Digital Neurectomy. This procedure is done to eliminate sensation to the heel of the foot. There are potential side effects associated with the surgery that need to be discussed between the veterinarian and the client before the surgery is performed. It is also very important to realize that the disease may involve the coffin bone, which will not be desensitized by the surgery. Please discuss the pros and cons of the surgery with your veterinarian.
Navicular Syndrome can be a devastating disease for any horse. Therefore, it is imperative to ensure that your horse has proper conformation with an appropriate hoof to pastern axis with an early break over point. A horse’s heels should always stay balanced. We recommend discussing your horse’s feet with your veterinarian, so that we can prevent Navicular. Prognosis for this syndrome is poor. It is a progressive, degenerative disease. Early intervention is crucial to help minimize the disease progression. Horses that suffer from Navicular Syndrome can return to athletic performance when treated early in the course of the disease.
If you have any questions regarding the above information or any questions/concerns in general, please contact Twin Valley VHS at 745-6642.
Dr. Justin Noble DVM
Twin Valley Veterinary Health Services