Caudal Heel Pain - The Dreaded "N" Word

Written by: Dr. Jay Altman

If you want to send chills up the spine of the owner of a competitive equine athlete, just mention the "N" word, Navicular. Navicular Syndrome, (formerly known as Navicular Disease) is often a debilitating condition that requires intense medical management coupled with a proper shoeing methodology in order to produce a comfortable and sound horse.

Navicular Syndrome typically has many factors and is bilateral, (affecting both of the front feet). Anatomical structures commonly involved in and affected by this lameness include the Navicular Bone, Navicular Bursa, Deep Digital Flexor Tendon (DDFT), Distal Interphalangeal Joint (Coffin Joint), Impar Ligament, and the supporting ligaments of the Coffin Joint. The syndrome manifests itself with a pain and inflammatory process that may include any or all of these structures, creating sensitivity in the caudal (back) 1/3 or 1/2 of the foot.

Just as with many lameness issues, early detection and treatment of Navicular Syndrome may decrease the potential degenerative nature of this condition. If the condition does progress, the horse can experience either initial or progression of demineralization and/or calcification of the bonny structures involved. The more these structures change due to this remodeling, the more difficult treatment and pain relief become.

Diagnosis of Navicular Syndrome requires many "tools", on the part of the veterinarian. A complete and thorough lameness examination, including a hoof tester evaluation, diagnostic nerve blocks, and radiographs of the foot are essential and are the most commonly utilized for the diagnosis of Navicular Syndrome. Additional diagnostic techniques may include joint blocks, ultrasound, thermo-graphic and nuclear seintographic examinations. Despite numerous techniques for diagnosis, I find that a diagnosis of Navicular Syndrome can be a bit of a challenge in certain cases. Some of the complicating issues include the fact that:

• Not all caudal heel pain is causes by the structures involved in Navicular Syndrome.
• Certain horses, under adverse conditions, can experience temporary pain in the Navicular region, which can either be alleviated with proper treatment or on the other hand, exacerbated, leading to permanent changes and a true disease process.
• Some horses with radiographic indications of Navicular Syndrome never show clinical signs of the disease (pain).
• A percentage of horses with Navicular Syndrome do not show any radiographic evidence of the disease.

For these reasons, I try to be careful before extolling a diagnosis of Navicular Syndrome. My preference is to use the phrase "caudal heel pain" until I am certain of the diagnosis.

Many quality treatments now exist for horses with Navicular Syndrome. The treatments include proper farrier care and therapeutic shoes, calling for an experienced and cohesive team of veterinarian and farrier. The term "proper" is used because each case and each foot must be analyzed and considered on an individual basis; there is no single proper method for therapeutic shoeing of Navicular Syndrome. Although, numerous specialty shoes are available, including: Egg Bar shoes, Heart Bar shoes, Digital Support shoes, and glue-on therapeutic shoes. Selection of proper shoes and shoeing angles may require multiple attempts by the veterinary/farrier team. Additional therapies include non-steroidal anti-inflammatory drugs (bute, banamine, ketoprofen), vasodilator drugs, vasomodulator drugs, joint therapies (Hylaronic Acid, Glucosamino Glycans), and steroids. The drugs may be administered orally, intravenously, or intra-articularly.

Hopefully you don't, but should you suspect one of your horses might have navicular syndrome or any other lameness, call your veterinarian. Remember that for many diseases and lameness issues early diagnosis and treatment is often advantageous.