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Discussion on Conformation and Navicular SynDrOme
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Moderator:
DrO
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Posted on Thursday, Aug 19, 2004 - 11:35 am:
Navicular synDrOme is frequently associcated with some types of poor hoof conformation, particularly low heels. There is a logical explanation for this. As heel height gets lower in relation to the toe height, the pressure on the navicular bone and tension of the deep digital flexor increase. Recently motion and force analysis supports this idea but there is also practical support:
Equine Vet J. 2004 Jul;36(5):431-5.
Relationship of foot conformation and force applied to the navicular bone of sound horses at the trot.
Eliashar E, McGuigan MP, Wilson AM.
Department of Veterinary Clinical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, UK.
REASONS FOR PERFORMING STUDY: Collapsed heels conformation has been implicated as causing radical biomechanical alterations, predisposing horses to navicular disease. However, the correlation between hoof conformation and the forces exerted on the navicular bone has not been documented. HYPOTHESIS: The angle of the distal phalanx in relation to the ground is correlated to the degree of heel collapse and foot conformation is correlated to the compressive force exerted by the deep digital flexor tendon on the navicular bone. METHODS: Thirty-one shod Irish Draught-cross type horses in routine work and farriery care were trotted over a forceplate, with 3-dimensional (3D) motion analysis system. A lateromedial radiograph of the right fore foot was obtained for each horse, and various measurements taken. Correlation coefficients were determined between hoof conformation measurements and between each of these and the force parameters at the beginning (15%) of stance phase, the middle of stance (50%) and at the beginning of breakover (86% of stance phase). Significance was defined as P<0.05. RESULTS: The force exerted on the navicular bone was negatively correlated (P<0.05) to the angle of the distal phalanx to the ground and to the ratio between heel and toe height. This was attributed to a smaller extending moment at the distal interphalangeal joint. There was not a significant correlation between the angle of the distal phalanx and the degree of heel collapse, and heel collapse was not significantly correlated to any of the force parameters. CONCLUSIONS: Hoof conformation has a marked correlation to the forces applied to the equine foot. Heel collapse, as defined by the change in heel angle in relation to toe angle, appears to be an inaccurate parameter. The forces applied on the foot are well correlated to the changes in the ratio of heel to toe heights and the angles of the distal phalanx. POTENTIAL RELEVANCE: Assessment of hoof conformation should be judged based on these parameters, as they may have clinical significance, whereas parallelism of the heel and toe is of less importance....for more on how this relates to diagnosis and treatment
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Member:
Suzeb
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Posted on Tuesday, Aug 31, 2004 - 3:03 pm:
Hello Dr. O,
Been mulling over this new article for some time  . As an owner of a horse with the hoof conformation described, what "new" force would have to applied to alleviate the pull on the DDFT over the Navicular bone? Also, I would like to know what is considered "Routine work and farrier care for the Irish Draught Horses used in this study?
Hope you can help  ,
Susan B.
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Moderator:
DrO
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Posted on Wednesday, Sep 1, 2004 - 6:33 am:
The main way to lessen the force excerted on the DDF's pressure on the navicular bone would be by elevating the heels. Routine farrier work is the work of dozens of different farriers using standard shoes on these horses.
DrO
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Member:
Miamoo
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Posted on Wednesday, Sep 1, 2004 - 11:34 am:
Do horses get navicular disease in the hind feet? I have only seen it in horses in the front.
Ella
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Moderator:
DrO
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Posted on Thursday, Sep 2, 2004 - 6:29 am:
Yes, diseases of the navicular bone (fracture for instance) and region occur in the back legs. However the condition of bilateral chronic heel pain known as navicular synDrOme is a rare condition behind. The reason is easy to understand, the condition comes from stress on the structures on and around the navicular bone and the front feet carry about 50% more weight than the rear, for more see Equine Diseases » Lameness » Diseases of the Hoof » Navicular Disease / SynDrOme.
DrO
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Member:
Miamoo
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Posted on Thursday, Sep 2, 2004 - 10:33 am:
Thank You Dr. O.
Ella
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Member:
Suzeb
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Posted on Thursday, Sep 2, 2004 - 11:28 am:
Dr.O,
Is there a common condition that occurs in the hind end with this type of conformation? Just curious because my horse has 4 "flat" tires so to speak. Thanks in advance.
Susan B.
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Moderator:
DrO
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Posted on Saturday, Sep 4, 2004 - 8:49 am:
It depends on the particulars Susan. Is the horse's hoof out of alignment with the pastern? If so you are placing stress on the joints of the foot and the deep digital flexor. But we do not have any well established equivalent to navicular in the hind limb.
DrO
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New Member:
Nrosen
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Posted on Friday, Aug 26, 2005 - 8:30 am:
An 8 year old mare owned by a client was diagnosed with navicular synDrOme last week. X Rays showed a bone spur on the coffin bone on one foot. She had been suddenly lame which led to the diagnosis. The examining vet found her sensitive in the heels to hoof testers. She was more lame on the right front which improved to a grade 1 lameness with nerve blocking. She was injected in the coffin bone with hyaluronate acid and steroids on both feet and degree pads were put on both feet and she now looks 100% sound. She had never shown what I thought were typical front foot lameness symptoms, pointing etc. Lameness occurred over a few days. What kind of prognosis would you expect given the rapid response to treatment? What are the risks of injecting the foot. She does dressage and does go well, carrying her weight on her hind end. Thanks for any advice you can offer us.
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Moderator:
DrO
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Posted on Saturday, Aug 27, 2005 - 11:29 am:
The problem with the diagnosis is that it specifically states the cause remains unknown: that is what synDrOme means. Since we don't know the cause there is no accurate way to prognose. However most acute onset lamenesses that resolve quickly don't turn into chronic problems.
DrO
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