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Thread: Laminitis Research Rocks Veterinary World

  1. #1
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    Wink Laminitis Research Rocks Veterinary World

    Unashamedly pinched from a UK forum:

    http://www.thehorse.com/ViewArticle.aspx?ID=18869

    Quote:
    Veterinarians and researchers around the world have been seeking a cure for laminitis for decades. While a cure remains elusive at present, several treatment options have been developed to help make laminitic horses more comfortable despite their condition. A team of researchers from New Zealand recently put one of the most common treatment methods to the test using biomechanical models, however, and found that it might not be as effective in treating the clinical signs of the disease as once thought.

    Laminitis is a disease that compromises the laminar junction, a 3-4 mm layer of soft tissue connecting the hoof wall to the coffin bone. In horses affected by laminitis, the coffin bone rotates within the hoof capsule, creating pain caused by abnormal pressure on some structures in the leg and foot.

    In some cases, veterinarians and farriers raise a laminitic horse's heels using therapeutic shoeing to increase the hoof angle based on the belief that the procedure relieves stress on the deep digital flexor tendon (DDFT) and laminae caused by rotation of the coffin bone.

    A recent study led by Glenn Ramsey, a PhD candidate at New Zealand's University of Auckland, examined how changes in hoof angles affect the load on the dorsal (forward-facing) laminar junction in the hoof.

    "This is the region where failure is observed, and the goal of hoof care interventions that attempt to manipulate the DDFT force is to reduce the load in this region," explained Ramsey.

    In the study the team biomechanical finite element models of equine hooves with palmar angles (the angle the bottom of the coffin bone makes with the ground) ranging from 0-15. Finite element analysis is a computerized method of, essentially, taking a complex problem and breaking it down into a finite number of simple problems. Using information on ground reaction force (the force exerted by the ground on a body in contact with it) and joint movement (the force that causes the joint to articulate about its center of rotation) acquired from a previous study, computerized models were used to simulate the conditions a real hoof would experience at a walk.

    Researchers then compared models using strain energy density (SED), "an indicator of stored elastic energy and, thus, localized load on the tissue," reported the team.

    The team found that:

    In all loading simulations, SED was lowest at the lower end of the laminar junction and increased upwards;
    The peak SED values for the highest palmar angle (15) was 1.3-3.8 times greater than the lowest palmar angle (0); and
    Models with lower palmar angles had a more even distribution of SED than did models with higher palmar angles.

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    So what does all this mean? The team's findings suggest that raising the palmar angle could, in fact, increase the load on the dorsal laminae rather than decreasing it, which could hinder the intended outcome of the treatment.

    Each case of laminitis is different, however, so horse owners should discuss potential therapeutic options for laminitic horses with their veterinarian and farrier prior to implementing treatment.

    The study, "The effect of hoof angle variations on dorsal lamellar load in the equine hoof," was published in the September 2011 issue of the Equine Veterinary Journal. The abstract is available online.
    .................................................. ..............................

    Raise your hand if you've also been so surprised by this finding (I mean, not surprised it's taken 'em this long to cotton on, but surprised that jacking up the heels leads to more stress on P3)

    What's that saying about 'truth'?

    Quote:
    According to the German philosopher, Arthur Schopenhauer, "All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident."


    There's a few forums I'd love to post this on but don't have the time for the resulting arguments!!! (not me, original poster but I don't either!!!)
    Last edited by gdh; 30-09-11 at 02:43 PM.

  2. #2
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    My barefoot trimmer never believe that raising the heels would help. He just trimmed the hoof as per normal and advised walking the horse slowly initially to stimulate the blood flow- it helped my horse!

  3. #3
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    This has been discussed elsewhere as well.

    I don't wedge laminitics (but never say never); equally I do not agree that zero degree palmar angle is good for laminitics (nor most sound horses) as the study leads one to conclude.

    1/ the study is model based and not in vivo

    2/ it does not consider other vectors involved with a live animal.

    Some comments from M. W. Myers, DVM

    The strain that increased was at the upper portion of the hoof wall and decreased at the lower end. They may have misinterpretted their data. The laminae tend to tear from distally to proximally not the other direction. This could interpret as beneficial rather than a problem.

    Strain measures deformation of the exterior hoof wall and not the stress on the laminae themselves. Measuring the external strain on the hoof wall may not directly correlate with the inner forces acting within the hoof capsule.
    and

    The strain that increased was at the upper portion of the hoof wall and decreased at the lower end. Since laminae tend to tear from distally to proximally I am not sure their model is correct. There are also hydraulic forces within the hoof capsule that enter into the equation and doppler ultrasound measurements as well as venogram images show that elevating angles tends to increase perfusion into the hoof while low and especially negative angles decrease this perfusion. This would indicate the hoof is benefitted by increased hoof angles (to a point).

    An interesting study, but there are many questions to consider and it contradicts live models from some differing studies.

    Once you have put a number of acutely laminitic horses into heel elevation and noted how much more comfortable the horse becomes in short order, this study appears to have a flaw in it somewhere.

    Aligning the pastern axis is usually the best first step. Most laminitic horses tend to do this if you note their radiographs. If they have a long low pastern axis they will have a lower palmar angle. Conversely, the upright horse will raise his palmar angle for comfort.
    More research needed.
    Last edited by ShoeMan; 30-09-11 at 03:55 PM. Reason: corrected in vitro => in vivo

  4. #4
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    Low heel, very short toe, rolled off walls and well padded sole in RX boot is what eventually reversed the rotation and relieved the pain that shoeing caused darkhorse3's foundered mare.

    I think there is a fundamental misunderstanding of the purpose of the laminae. It isn't to support the pedal bone by connecting it to the wall of the hoof.

    The laminae is a shock absorber (and blood supply) between the semi rigid hoof wall and the very strong hoof bones and connective tissues. The pedal bone stands on its own with cushioning, it isn't carried on the hoof wall. The laminae can't support that without being damaged.

    Sorry, that is very simplified and I do know there is far more to it than that and I would like to point out that though committed to "barefoot" I have never, personally had a horse damaged by a farrier and we had grand prix dressage and jumping horses.
    Last edited by Bats_79; 30-09-11 at 03:30 PM.
    "One must avoid using force, for I have never seen anything positive come out of a horse if such is the case".

    Antoine De Pluvinel

  5. #5
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    In my experience and opinion there are many cases that do not benefit from extreme wedging. I would also suggest that here in Australia we are perhaps less inclined to wedge markedly compared to some in the USA. Some workers there will wedge 17 18 degrees - most of us here are shy of that. For me I was concerned paticulArly in the very acute phase about the application of such creating shearing on the already fragile dorsal laminar and vasculature.

    Each case should be judged on their individual merit - clinical picture , radiographs, venograms and stage of disease.

    There is not a " recipe" for the treatment of all cases!

    I think more research is required in vivo ideally. Often the in vitro situation is very different to that on vivo!

  6. #6
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    Quote Originally Posted by Seahorse01 View Post

    Each case should be judged on their individual merit - clinical picture , radiographs, venograms and stage of disease.

    There is not a " recipe" for the treatment of all cases!

    I think more research is required in vivo ideally. Often the in vitro situation is very different to that on vivo!
    Yes, couldn't agree more SH01. First consideration is the state of the hoof pre disease, chaos theory reigns from then on.

    (And I have corrected my mistake above, should have said in vivo)

  7. #7
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    I was just going to correct myself too - model versus vitro versus vivo - all can be very different!

    Just seen acute laminitic with 5 degree rotation but extreme toe! This won't go in a wedge!!!!

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