Navicular Disease in Horses

• Navicular Syndrome
• Chronic Palmar Foot Pain
• Chronic Heel Pain Syndrome

  by Robert N. Oglesby DVM

The diagnosis of "navicular disease" has been around for a long time and at one time was one of the most frequent diagnosis made for chronic foot lameness. Old habits die hard and so it is with this diagnosis but it has not gone easy. First lameness specialists and researchers of navicular disease replaced the term "disease" with the term "syndrome”. A syndrome can be described as a constellation of symptoms seen in a number of cases, but the cause of the symptoms is unknown. In this case the finding of:

• chronic bilateral pain
• that localized to the foot by blocking out with a posterior digital nerve block
• and a cause could not be readily identified

is the widest description of this syndrome. Some would include radiographic changes in the architecture of the navicular bone as a requirement. But the problem with this were the many horses with the physical findings but not the radiographic changes and then there were the horses with the radiographic changes that were sound.

More recently navicular syndrome has been thrown out all together for the more accurate "Palmar Foot Pain" or "Chronic Heel Pain Syndrome" (CHPS). After all we don't know if the navicular bone or its ancillary structures are responsible and recently better diagnostic techniques have shown that many structures in the heel region are responsible for chronic heel pain in horses.

The first goal of any horse with chronic heel pain (CHP) is to try and get a accurate diagnosis. Advances in diagnostic techniques including a better understanding of the effects of local anesthesia, new radiograph positions, ultrasound, and magnetic resonance imaging, have greatly increased our ability to find lesions in the foot. It is important to note that once you have a probable diagnosis you no longer have CHPS and you have a much better idea as to what proper therapy should be and prognosis of the horses future athletic ability.

Despite your best efforts sometimes the cause of the lameness remains undiagnosed. In these cases therapy directed at relieving pain and inflammation and relieving excessive strain on the structures in the heel area through trimming and shoeing techniques. This article describes the history, clinical signs, and diagnosis of causes of chronic heel pain. Links to articles on more specific diseases are provided. If the problem remains undiagnosed the article goes on to explain symptomatic therapy and trimming to increase the chances your horse may return to some degree of athletic ability or even soundness.