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Articles & Information
FROM THE HOOFCARE & LAMENESS ARCHIVES Navicular Bone Remodeling Several recent lectures by Dr. Roy Poole of the University of California at Davis have added to his reputation as a leading voice for reason in the diagnosis of "navicular-like" lameness in horses. "Some people collect stamps. I collect navicular bones," he said as he opened his lecture at the American Association of Equine Practitioners Convention in San Francisco in December. As
a pathologist, Poole sees navicular bones after the fact. He has been
able to separate one tiny part of the horse's foot into a world of its
own, and has come up with marvelous facts, figures, and even a
personality for his navicular bones. "It looks like a bone that's
doing a swan dive," he began. "But its arms are attached by
ligament to P1." Dr.
Poole's primary findings on navicular disease and navicular bone
function have been summarized here before. Briefly, he feels that
radiographic changes to the synovial fossae of the bone, often called
lollipops, cones, etc. are not key to a relevant diagnosis of
navicular disease. This stand by Dr. Poole is contradictory to the
theory of other researchers. Dr.
Poole maintains that the navicular bone simply must change to
withstand the pressure of racing or sport over the course of its life.
To show the relative remodeling, he displayed the navicular bones of a
nine-year-old rodeo quarter horse, a two-year-old Thoroughbred, and a
newborn foal. Remodeling is not all bad, stressed Dr. Poole, and it shouldn't be misconstrued in analysis. Some horses need to remodel their navicular bones for biomechanical efficiency or because of their conformations. Unsuccessful remodeling can be considered navicular "disease". During remodeling, fluid may leak and cause the deep digital flexor tendon to adhere to the bone. Pedal osteitis and bone remodeling from laminitis are similar conditions. A
magnetic personality is a strong possibility in a legion of top
performance horses with navicular-type lamenesses these days. Fitted
with tiny 3/8" button magnets glued into slot-like
"pockets" about one inch above the shoe in their hoof walls,
these horses are reining, cutting, show jumping, eventing, and
piaffing through dressage tests that they might otherwise miss due to
subtle lameness conditions. Sometimes called New Zealand magnets, they
are believed to transmit a five-pound therapeutic magnetic charges
through the navicular bone. Before you dismiss this as a California fad, think again: the magnets originated in the Standardbred industry and are used by several of the Northeast's top show farriers, who pay about $75 per pair of magnets from dealers like Summit Tech in New Jersey. What the trainer or owner has to pay is anyone's guess. This article originally appeared in Hoofcare & Lameness: The Journal of Equine Foot Science and is available for your personal use only. Re-publication is prohibited without the express written permission of Hoofcare & Lameness. Detailed information on this and many other hoofcare topics can be found in Hoofcare & Lameness publisher Fran Jurga's award-winning guide to hoofcare, "Understanding the Equine Foot". For more information, or to order, click here Back to the articles table of contents Write to H&L: PO Box 6600, Gloucester, MA 01930. Tel 978 281 3222; fax 978 283 8775. Email webinquiry@hoofcare.com. Internet http://www.hoofcare.com. © 1998
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