Navicular Disease/SyndromeBy: Dr. Lydia Gray
Navicular disease generally refers to progressive degeneration of the navicular bone, the small bone in the hoof that lies behind the coffin bone or third phalanx. Navicular syndrome is used to describe any condition causing pain in the area of the navicular bone or the heel, including the navicular bursa, deep digital flexor tendon, coffin joint, or any of several ligaments.
Prescription joint products such as Legend® and Adequan® are often administered to horses with navicular, and it may also be helpful to provide an oral joint supplement with similar active ingredients (i.e. Glucosamine, Chondroitin Sulfate and Hyaluronic Acid). Because fighting inflammation is key to keeping the horse comfortable and supporting stressed tissues, natural anti-inflammatories such as MSM, Omega 3 Fatty Acids and certain herbs may be beneficial.
It is usually not difficult to localize lameness in the horse’s heel with an examination that includes applying a hoof tester, flexing the lower limb, standing the horse on wedges, and blocking local nerves. However, determining exactly what structure within the hoof is causing the pain can be a challenge. X-rays have always been the basis of a navicular diagnosis, but newer methods such as x-rays with contrast dye, ultrasound, bone scan (nuclear scintigraphy) and especially MRI appear to be better at identifying which specific structures are involved.
If a specific structure within the hoof can be identified as diseased or injured, anti-inflammatories such as corticosteroids or Hyaluronic Acid (Legend®) may be injected directly into the area. Prescription non-steroidal anti-inflammatories (NSAIDS) such as bute (phenylbutazone) and Banamine® (flunixin meglumine) are commonly used to relieve pain. The human drug isoxsuprine, a vasodilator which increases blood flow, is often prescribed because one theory suggests the disease is caused by lack of blood flow to the bone.
Corrective shoeing is a large component of the overall treatment plan for horses with navicular. Mild exercise is preferred over stall rest. Extracorporeal shock wave therapy and desmotomy (cutting) of local ligaments are being explored as treatments. Cutting the nerves to the foot (palmar digital neurectomy) remains a last resort.
- Why did my horse develop navicular?
- How much longer will I be able to compete him?
- If he has the neurectomy, will he still be able to feel his foot and be safe to ride?
Further Reading for You
From The Horse Journal:
- Diagnostic Advancments: No more “foot sore” diagnoses, September 2004
- Navicular isn’t a “one-size-fits-all” Problem, January 2002
- Navicular Disease Pain, January 2008
Further Reading for Your Veterinarian
Harper J, Schmuacher J, Degraves F, et al. Effects of analgesia of the digital flexor tendon sheath on pain originating in the sole, distal interphalangeal joint or navicular bursa of horses. Equine Vet J. 2007 Nov;39(6):535-539.
Sherlock Ce, Kinns J, Mair TS. Evaluation of foot pain in the standing horse by magnetic resonance imaging. Vet Rec. 2007 Dec 1;161(22):739-744.
Dyson S, Murray R. Verification of scintigraphic imaging for injury diagnosis in 264 horses with foot pain. Equine Vet J. 2007 Jul;39(4):350-355.
Rijkenhuizen AB. Navicular disease: a review of what’s new. Equine Vet J. 2006 Jan;38(1):82-88.
About Dr. Lydia Gray