Hallmarq Standing MRI: Hoof Conformation from the Inside Out

 

This sponsored blog post is the latest in a series produced in partnership with Hallmarq Veterinary Imaging. Thanks to Hallmarq for their support of The Hoof Blog. This video explains the process known as "Standing MRI" of the equine foot using a Hallmarq system. The units are in use around the world.

Which came first: the chicken or the egg? 

Forget everything you “know” or think you know, about the relationship between foot shape and lameness. What matters in this age of evidence-based veterinary medicine is 1) what can be demonstrated and measured; 2) reliably repeating what was demonstrated; and 3) documenting the data of the measures.

If some hoof research makes you yawn and seems to be proving what is already obvious to you, remember that building a better tower of knowledge means that we know we can count on the blocks at the bottom of the tower. They must be proven before we can move on.

Hoof science is shy a few blocks. The tower is still on the drawing board. In order to document what you "know"via the scientific process, it is necessary to approach it from different angles so that it can be measured.

The deep digital flexor tendon (DDFT) is the most common site of damage in the foot identified by standing MRI scanning of sport horses. As you know, this tendon runs down the leg and attaches to the bottom of the coffin bone (P3). The three arrows added to this scan are directing the eye to the portion of the DDFT which, in this Irish horse, has a lesion that looks like a split. Normally tendon would be solid black. The recent study in England looked at a group of horses with similar injuries of the DDFT and measured for similarities in the conformation of foot structures. (Photo courtesy of Troytown Equine Hospital, Co. Kildare, Ireland.)

When researchers at Great Britain’s Royal Veterinary College wanted to get to the bottom of this age-old conformation to lameness relativity issue, they used Hallmarq standing MRI images to collect data that could be measured. The group of investigators worked under the direction of Renate Weller Dr Med.Vet, PhD, MRCVS, FHEA, senior lecturer in diagnostic imaging and locomotor biomechanics, at the RVC's Structure and Motion Laboratory.

Tim Mair, BVSc, PhD, DEIM, DESTS, DipECEIM, MRVCS is an author of the paper and a partner in England's Bell Equine Veterinary Clinic, where Hallmarq Standing MRI scans were sourced by Hallmarq's Nick Bolas. Also from the private sector, and a recent RVC graduate, Jonathon Dixon BVetMed MRCVS of Rainbow Equine Clinic was involved with the study.

The premise of the study is an inside-out refinement of hoof confomration. Instead of measuring the circumference of the hoof capsule and the contour of the coronet, they measured or calculated characteristics of the structures inside the foot. The availability of real-world lameness cases' standing MRI scans meant that the researchers had the luxury of a library of almost 200 images of injured or lame feet that met the study's criteria.

The MRI would have been originally made to assist in a definitive diagnosis on a lame horse. The clinician noted that the MRI showed a lesion in the deep digital flexor tendon or injury to the navicular bone, etc.

The researchers from the Royal Veterinary College undertook the project of evaluating these standing MRI scans not in the context of a single lame horse, but in the hopes that they would find other similarities in the feet of horses that had received the same diagnosis.

Once again: don’t assume anything, but see what the MRIs had to say.

If you overlaid a dozen images of the same type of injury from a dozen horses’ hooves, would the hoof capsules line up and show similar characteristics?

The researchers found that there indeed was similarity in the measurements of feet with the same diagnosed injuries.

What type of horses and lameness?

The mean age of horses in the study was between ten and eleven years; the average grade of lameness was approximately a “3” on a scale of 1 to 10. Breeds included 37 Warmbloods, 51 Thoroughbreds and Thoroughbred crosses, 22 Irish sport horses, 15 Irish draft horses and Irish draft crosses, 11 Cobs and 43 horses of other various breeds.

The horses had been diagnosed with many types of injuries, including lesions of their deep digital flexor tendon (DDFT), navicular bone (NB), collateral ligaments of the distal interphalangeal joints and

25 other structures.

What was measured? C, sole angle; D, toe angle; H, heel angle; N, deep digital flexor tendon angle; PL1, plumb line 1;  PL2, plumb line 2;  MA1, proximal moment arm; MA2, distal moment arm; SI, distal phalanx length; LC, toe length.

Sole angle

Sole angle is a relatively new term in the lexicon of foot anatomy. It is not the angle formed where the sole meets the wall, as documented in some studies. Its number is not describing the sole at all, in fact, rather the concavity of the coffin bone.

Dr. Weller took the time to explain it for Hoof Blog readers as the concave sole surface of the coffin bone to horizontal angle. Check the diagram to see the point on the mid-sagittal MRI scan where this angle is measured.

Dr Weller explained: "The issue we have in practice is that the sole angle we measure on radiographs does not correspond to the angle at which the DDFT actually attaches, but (rather we measure) the lateral and medial coffin bone borders.

"This (angle of the coffin bone) can be taken as an approximation at best, since the concavity of the coffin bone differs between horses. So some may have little concavity and in those horses the radiographic measurement will correspond quite well to the insertion angle of the DDFT, (however) some horses may have (a) very concave coffin bone and in these the radiographic measurements will not represent the DDFT insertion angle.

"The reason we care about this angle is that it is strongly related to the strain the DDFT experiences and hence the pressure this tendon exerts on the navicular bone," she concluded.

Measurement results

• A larger sole angle was associated with combined deep digital flexor tendon (DDFT) and navicular bone (NB) lesions, but not with NB lesions alone.
• A more acute angle of the DDFT around the NB was associated with DDFT and NB lesions.
• A lower heel height index was linked with DDFT injury.
• The larger the sole angle, the smaller the likelihood of a DDFT or NB lesion.
• Measurements of the feet in the study contradicted findings of other studies.

Why is this study important?

Taking measurements from diagnostic images is not a new idea, so why is this study newsworthy? 

Previous studies have shown that certain conformational traits--sole angle in particular--increase forces acting on the DDFT and NB in sound horses. This study supports these findings by showing that conformational parameters are associated with DDFT and NB lesions in lame horses.

Standing MRI is done with the horse
bearing weight on the injured limb

The researchers noted that while this study shows an association between certain conformation parameters and foot lesions, foot conformation cannot be identified as causative factor of lameness. "Foot conformation may change as a consequence of lameness," they concluded.

Which brings us back to the chicken and the egg.

Future studies at the RVC will focus on dynamic conformation by investigating foot-surface interaction in lame versus sound horses, which may eventually open a preventative and/or therapeutic window for horses in the process of developing specific lesions within the foot.

Relevance of this study

The study's findings emphasize the deep digital flexor tendon's influence on the conformation of the foot and that it plays a leading role in many foot lameness problems. The DDFT's angle within the foot and the relative concavity of the distal phalanx (P3) (as measured by sole angle) may become routinely documented in the future.

Studies like this one are changing the way that foot structures are evaluated and measured. Standing MRI scanning provided three-dimensional evaluation of the foot, expanding the diagnostic field for the most precise possible examination of foot tissues and for the most accurate measurement protocols for scientific relevance. 

But Weller’s team’s emerging protocols for evidence-based hoof evaluation provide the sport horse and racing worlds with a basic building block that could one day be used on important studies to answer questions on equine welfare, prevent pain and increase a horse’s useful years. The hoof is one of the last frontiers of equine science, and the Royal Veterinary College is dedicated to learning more about it.

Research can’t be any more relevant than that.

To read the full paper: Kate Holroyd, Jonathan J. Dixon, Tim Mair, Nick Bolas, David M. Bolt, Frederic David and Renate Weller; Foot conformation in lame horses with different foot lesions diagnosed, published online in The Veterinary Journal, September 2012.

 To learn more about Hallmarq Veterinary Imaging and standing MRI technology for horses:

• "Like" Hallmarq Equine MRI Facebook page;
• Follow @HallmarqMRI on Twitter;
• Subscribe to the hallmarqvetimaging channel on YouTube.com;
• Watch for a growing equine distal limb Hallmarq MRI image gallery on Flickr.com.
• Visit the Hallmarq.net web site. (Plan to spend some time there!) 

© Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.  

Follow Hoofcare + Lameness on Twitter: @HoofcareJournal

Read this blog's headlines on the Hoofcare + Lameness Facebook Page

 

Disclosure of Material Connection: Hoofcare Publishing contracted to receive compensation for compiling this post but the veterinary expertise and opinions in the article were provided by John Peloso DVM and Hallmarq Veterinary Imaging.  The information contained in this article is for informational purposes only, and should not be used to replace professional veterinary advice for your horse. Visitors to the website are responsible for how they choose to utilize this content. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

Hallmarq Standing MRI and Chronic Equine Foot Lameness: What’s Going On Inside the Foot?

Sport horse lameness requires a diagnosis to pinpoint the injury site and a prognosis to predict when and if the horse might return to training. The veterinarian chooses from a set of alternative plans to gain recovery based on restricting the horse to stall rest, turning him out, or following a prescribed limited exercise program. The program is determined by the site of the injury and the clinician's knowledge of and experience in successfully treating that injury site. If the injury isn't properly or fully diagnosed, facets of the recovery plan--including medications and adjunctive hoofcare--might not be effective, time may be lost and the horse's chances at returning to his former level of performance are jeopardized.

The hoof capsule is the horse’s best friend: it’s a protective covering, a shield against rocks and bumps, and a tractable aid to locomotion. If the horse had to gallop on a soft digit, could he gallop at all?

The tough shell of his hoof wall is the horse’s best friend--until something goes wrong inside the foot. Then it takes sophisticated imaging equipment to see what’s going on inside that wall, and beneath that sole and frog. When we want to know what’s going on in there, it’s time for technology to take over.

The density of the outer hoof capsule protects the horse from many injuries. But when there is a problem inside the foot, the hoof capsule makes it difficult to diagnose the severity of injuries and make a definitive prognosis for recovery. (Nottingham Vet School photo)

A recent study at the Marion duPont Scott Equine Medical Center in Leesburg, Virginia delved into some details of cases of chronic, unresolved foot lameness. Might these cases have something in common, besides that the horses were all lame in one front foot? The researchers wondered, and compared the horses’ records.

The study's lead author is
Santiago Daniel Gutierrez-Nibeyro,
DVM, MS, DACVS, now a clinician
at the University of Illinois
College of Veterinary Medicine

While many studies have logged in data about test-case horses with specific acute injuries revealed only by MRI--deep digital flexor tendon lesions in sport horses are prime examples--this study looked at a larger population of horses that had been lame for some time (from three months to five years) and which had not received the benefit of an MRI before they were referred to the hospital for further testing.

Each of the horses had responded favorably to a palmar digital nerve block in the lame foot, so the clinician was confident that the horse’s pain source had been isolated. MRI was performed if clinical and radiological findings did not provide a definitive diagnosis and if the owners elected further examination.

Another thing the cases had in common is that, after referral, each of the horses had been scanned using the same MRI technology: the Hallmarq Veterinary Imaging “standing MRI” system installed at the hospital in Leesburg in 2007.

Horses with chronic forefoot lameness were selected for the study. A Hallmarq standing MRI scan was employed to look for damage to soft tissue structures in the coffin joint and navicular zone.

The veterinarians selected 79 horses that fulfilled the selection criteria for the study and began to compare their records. The biggest thing that the horses had in common was that the MRI scans revealed that almost all of them--74 out of 79--were actually showing more than one structure in the foot with an alteration.

In most (52) of the 74 horses with more than one change, the multiple abnormalities were not of equal severity.

What types of injuries did the MRI scans reveal on these chronically lame horses?

• 78 percent of the horses had a navicular bone lesion in the lame foot, along with another injury;

• 58 percent of the horses showed evidence of navicular bursitis (inflammation to the bursa, or fluid-lined sac between the navicular bone and the deep digital flexor tendon at the back of the coffin joint);

• 54 percent of the horses showed evidence of damage to the deep digital flexor tendon;

• 53 percent of horses demonstrated some degree of effusion (excess fluid) of the coffin joint; and

• 39 percent of the horses were suffering from collateral ligament desmopathy of the coffin joint.

Who were these horses? Breeds included Thoroughbreds (24), Warmbloods (36), Quarter Horses (9) and others (10). Occupations comprised jumping (37), eventing (12), dressage (17) and pleasure riding (13). The mean age was nine years old, but ranged from four to 24.

What’s the take-home message from this research?

In standing MRI, the horse
does not require anesthesia

If you’ve been reading the Hoof Blog for a while, you already know a good bit about Hallmarq’s standing MRI technology, which is now available in dozens of veterinary clinics around the world. MRI was the next level of diagnostic imaging for horses whose injuries were not revealed by other systems or, in the case of navicular changes visible on radiographs, would benefit from a more detailed evaluation.

Not so long ago, we would have labeled these horses as simply having a chronic foot pain condition or, more likely “navicular disease”. Farriers would try different shoeing techniques or trims, hoping to hit on a magic combination of support and comfort. Pain medication, coffin joint injection and perhaps even neurectomy would be on the menu. Some horses recovered sooner, some horses recovered later, some horses stayed lame.

Having access to MRI is much like calling in Sherlock Holmes when the police have failed to solve the crime. MRI results can often be surprising, as we see here, when the scan is expected to yield a given result and does, but also reveals more information than anticipated.

The deep digital flexor tendon (arrows) is a common site of injury in sport horses. While some injuries or abnormalities of the navicular bone can be seen on radiographs, lesions to the tendon require imaging that reveals the soft tissues of the inner foot.
(Troytown Equine Hospital image)

The identification of multiple injury sites in the foot is critical if the lameness is to respond and recover. In 2003, papers by Dyson and Murray in Great Britain and by Schneider and Sampson in the United States used MRI to document that equine foot pain often can be traced to multiple structures. This important new consciousness has been a critical factor in the growing appreciation of using MRI as a diagnostic tool, and the Virginia study certainly confirmed those findings in a large number of horses.

A benefit of the standing MRI system for evaluating horse foot lameness is that the horse is not required to undergo anesthesia. The horse stands on all four feet throughout the procedure, which may be performed as an “out-patient” type of appointment at a vet clinic that is equipped with the Hallmarq system.

This research was part of a series of MRI-related studies on foot lameness conducted by Santiago Daniel Gutierrez-Nibeyro, DVM, MS, DACVS as a component of his Masters in Science degree. The entire set of research papers is a tremendous asset to anyone wishing to understand how MRI imaging fits into the bigger picture of equine foot lameness diagnosis and treatment.

To learn more:

Standing low-field magnetic resonance imaging in horses with chronic foot pain by Gutierrez-Nibeyro, Werpy and White published in March 2012 in the Australian Veterinary Journal

Outcomes of Medical Treatment for Pathologies of the Equine Foot Diagnosed with Magnetic Resonance Imaging by Santiago Daniel Gutierrez-Nibeyro, M.V.

To learn more about Hallmarq Veterinary Imaging and standing MRI technology for horses:

• Visit and "like" the Hallmarq Equine MRI Facebook page;
• Follow @HallmarqMRI on Twitter;
• Subscribe to the hallmarqvetimaging channel on YouTube.com;
• Watch for a growing equine distal limb Hallmarq MRI image gallery on Flickr.com;
• Visit the Hallmarq.net web site. (Plan to spend some time there!)

© Fran Jurga and Hoofcare Publishing

Follow Hoofcare + Lameness on Twitter: @HoofcareJournal

Read this blog's headlines on the Hoofcare + Lameness Facebook Page

 

Disclosure of Material Connection: This blog post is sponsored by Hallmarq Veterinary Imaging. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

Racehorse Fetlock Screening Via Standing MRI Could Identify Horses at Risk for Condylar Fractures of the Fetlock

If there is one thing that we all learned by watching the Kentucky Derby this year, it was the term "condylar fracture". Watching first Battle of Hastings and then Archarcharch load into the horse ambulance was the low point of the day.

Are you one of the people who just shrugs and says, "That's racing!" or are you one of the people who asks, "Why? Why? Why?"

Maybe this article will raise the eyebrows of people in both camps and get them both saying, "What if..."

So what if...

What if a standing MRI could help identify horses with potential fetlock problems before any injury ever even happens? It's possible, and that's the prospect that equine practitioner John Peloso of Equine Medical Associates of Ocala, Florida put forward in March in an article in Thoroughbred Times.

Little did he know how timely the article would be six weeks later!

Let's start with the injury. Condylar fracture means that the portion of the long bone that was broken was the condyle. When you look at the end of the cannon bone, you see a ridge in the middle, between two rounded bulbs, called condyles.

The fetlock joint surface can be subject to a lot of wear and tear, as well as evidence of a degenerative condition, that might now show on a radiograph but might be visible via MRI. (John Peloso DVM photo)

The condyles sit in the fetlock joint and rotate within it, like balls in a socket, as the horse flexes his lower leg. Battle of Hastings' fracture was the medial (rough translation: inner side of the limb) condyle, whereas Archarcharch's injury involved the lateral  (rough translation: outer side of the limb) condyle.

Racehorses are especially prone to condylar fractures. Something (trainers like to call it "a bad step") causes increased pressure on the condyles in the fetlock joint. Normally a horse is fine but sometimes the condyle fractures, to varying degrees. A radiograph will show what looks like a crack in the cannon bone in the condyle area.

Thoroughbreds "Make It or Break It"

In his article, Dr Peloso reminds us that the process of building and creating an equine athlete is dependent on the horse's ability to "remodel" his bones.

The rigors of training cause a horse to continually lose bone and then replace it. In a healthy normal horse, the resulting replacement is more dense than the original.

But in some horses, the lost bone is not adequately replaced or fortified. This is called non-adaptive bone modeling. The effects of training may actually weaken the bone rather than fortify it.

If you have looked at a good radiograph of a horse's fetlock and cannon bone, you know that bone has different density values, and yet the inadequate bone modeling syndrome is deep in the bone and difficult for a radiograph to show. The depth of the problem means that the tissue around the joint doesn't swell, either. It's invisible.

MRI scans the fetlock in 3-D

Which horse would you bet on? The horse on the left had not begun training; the horse on the right shows mild thickening of the subchondral bone in the condyle region. (John Peloso photo)

Dr Peloso recommends the use of standing MRI to evaluate racehorses. MRI scans the fetlock in three dimensions and shows what's going on with the soft tissue in and around the joint as well as the architecture of the bony column itself. And with standing MRI, the horse does not need general anesthesia; trainers are reluctant to schedule their horses in training for anesthesia.

Standing MRI allows the horse to stand in a natural position while the scanning goes on. The horse is sedated but does not need general anesthesia. (Hallmarq Veterinary Imaging photo)

Certainly there is no way to know how many injuries can be prevented by monitoring fetlocks for non-adaptive bone remodeling. But in human medicine, MRI is the modality of choice to routinely detect almost-invisible stress fractures in athletes.

Dr Peloso noted that standing MRI screening of the fetlock is commonly performed in England, Ireland, France and Dubai, where many vet clinics are equipped with standing MRI units and may screen as many as two to three racehorses per day.

What veterinarians like Dr. Peloso hope to help trainers avoid: two examples of the early stages of condylar fracture of the fetlock. The red arrows are pointing to white crack-like lines that indicate a fracture has begun. (John Peloso photo)

Of course, you have to wonder why this happens at all: why are some horses normal? Why is it that the bones in other horses--horses who look and act perfectly healthy--just don't adapt properly?

Those are big questions. MRI can't answer those but a racehorse monitoring protocol of standing MRI sounds like a hopeful proposal that could possibly save some American horses' lives, careers or months lost from training. It could be that famous "ounce of prevention" that is worth many pounds of surgery, layup and rehabilitative cure.

Thanks to the kindness of our friends at Thoroughbred Times, we're able to post the entire article by Dr Peloso here on the Hoof Blog. You'll find an interactive window at the end of this article. Use the controls at the bottom of the document window to enlarge the text or scroll through the pages.

To contact Dr Peloso about his work on bone remodeling in Thoroughbreds, please contact John G. Peloso, DVM, MS, Diplomate ACVS, Equine Medical Center of Ocala, 7107 West Highway 326, Ocala, Florida 34482.

To learn more about standing MRI, visit Hallmarq Veterinary Imaging on the web.

Also on the Hoof Blog:

• Hallmarq Veterinary Imaging Presents Dr Sue Dyson's Patient, A Showjumper Who Wanted to Stay on the Left Lead
• No Farrier, No MRI: Diagnostic Imaging Sessions Begin With Careful Un-Shoeing
• Hallmarq Veterinary Imaging Looks at the Statistics of Equine Foot Lameness: New Diagnostics Document More Precise Damage to the Feet of Sport Horses
• More information and images appear regularly on Hallmarq's Facebook page
• Follow Hallmarq on Twitter: @HallmarqMRI

Thoroughbred Times 032511 Hallmarq Benefits of MRI Peloso

Article reprinted with permission from
Thoroughbred Times
 

Tweet

 

Disclosure of Material Connection: Hoofcare Publishing contracted to receive compensation for compiling this post but the veterinary expertise and opinions in the article were provided by John Peloso DVM and Hallmarq Veterinary Imaging.  The information contained in this article is for informational purposes only, and should not be used to replace professional veterinary advice for your horse. Visitors to the website are responsible for how they choose to utilize this content. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

No Farrier, No MRI: Diagnostic Imaging Sessions Begin With Careful Un-Shoeing

If you’re a farrier or horse owner who is new to equine MRI, you might be surprised to learn that most horses couldn’t have an MRI without the help of farrier skills.

That’s because horses that are shod must have their shoes removed before the MRI process can begin. This could be done before the horse leaves home, but it is usually done at the vet clinic where the MRI will be done, since the horse may need to be trotted or lunged as part of the diagnostic process.

An MRI session begins long before the horse's limb is scanned. It begins with an exam and the removal of both front or hind shoes, if the horse is shod.

For advice on the gentle art of shoe removal, Hoofcare + Lameness went to one of the world’s best authorities, Dave Duckett FWCF. A former farrier instructor at the national schools in Great Britain and Ireland, Dave is an undisputed expert analyst on the fine points of shoeing and unshoeing a horse, as his many world championships and other titles attest.

Duckett reminds us that a lame horse that is having an MRI may have some resistance to standing on three legs during shoe removal. It may also resent having its hoof walls tapped with the hammer to cut the clinches. For this reason, it may be safest to do the work at the vet clinic.

  Pulloffs should be used from the heel forward, gently removing the shoe without harming the hoof wall, but it is best to remove the nails with a creased nail puller. (Michael Wildenstein file photo)

Normally, a farrier might rasp off the clinches and an apprentice would go to work loosening the nails and then wrenching the shoe off the foot. With the shoe will come the nails, but farriers know full well that some may break. It may not happen often, but nail fragments can remain in the foot.

When and if this happens on the day an MRI is scheduled, the fragment will need to be found and removed, since any metal might disturb the magnetic function of the scanning system.

There are many reasons that nails break off. Duckett remarked that nails commonly corrode and break in the feet of horses that have been standing in urine-soaked bedding or manure-filled pens. The longer a shoe has been on, the more likely the nails are to break on any shoe, he added.

The design of the shoe itself can cause a nail to break off; the shape of the nail hole may be wrong for the size or style of nail that was used, so the nail fractures under the head. If the nail hole is too small, the edges of the hole shear the side of the nail as it passes through, weakening the shank, increasing the likelihood of fracture, and possibly creating soft steel dust particles that are carried up into the hoof wall. “The shoe doesn’t give, the nail does,” Duckett said, “and it usually fractures under the head.”

Cross-section of toe nails in foot, showing clinches (Michael Wildenstein file photo)

Duckett also warned about machine-made shoes that are hot fit, then quenched before nailing. This hardens the steel of the shoe around the hole, so the soft steel of the nail is likely to shear more as it passes through.

The constant expansion and contraction of the horse’s foot causes stress to the nail inside the wall, and can also lead to nail fatigue and even breakage, usually on the inside heel or both heels, according to Duckett.

It's safer to cut the clinches and pull the nails through the wall rather than rasping the clinches off and thinning the hoof wall of a horse that may already be lame. (Michael Wildenstein file photo)

So, instead of rasping off the clinches, or even just bending them back, the clinches should be cut off; this can be a challenge for someone not accustomed to finding the clinches in a recently shod foot, especially on the inside wall.

Creased nail pullers allow careful remove of each nail; the jaws can get down into the crease of the shoe. (Michael Wildenstein file photo)

Once the clinches are cut, each nail should be gently pulled through the foot with the creased nail pullers with a continuous pull, not a yank. Vet clinic farriers quickly learn to count their nails, check each one for its full length, and keep them in a little tray or cup to account for each foot’s nails.

Duckett pointed out that some clinches, if not cut, will break off occasionally and be lost inside the foot. This can be an inconvenience if a horse is scheduled for an MRI. He said that an experienced farrier will be able to pop a nail into the old hole and extricate the lost bit of metal.

The unshod foot will be cleaned and examined. As Hallmarq’s Nick Bolas pointed out, metallic dust can also be created by a rasp or by rust from shoes or the horse’s environment.

And that just won’t do for a horse that has a date with a huge magnet. Any sort of metal residue on the hoof wall or inside needs to be removed before the scanning begins.

Nail holes can be flushed with a cleaner—I fully expect a special product to enter the market any day now! A product like Life Data Labs’ Hoof Disinfectant is probaby found in most farriers' trucks and will do the job.

  Even the tiniest artifacts show up and can be magnified in an MRI scan. In this image, you can see a few glitches along the hoof wall. (Hallmarq MRI image)

10 TIPS FOR MRI SHOE REMOVAL SUCCESS

Working with Hallmarq Veterinary Imaging Systems, Hoofcare + Lameness came up with these tips for horse owners, clinics and farriers for pre-MRI hoof prep:

1. Owner: ask the vet clinic who will be pulling the shoes. Some owners may prefer to schedule a farrier appointment and make sure that the horse's regular farrier does the work. The owner should make sure that this farrier knows what s/he is expected to do so the correct tools will be on hand. It is most convenient to have the work done at the clinic.

2. Owner: Make sure that a farrier with Hallmarq MRI prep experience will be doing the work so that the procedure described above will be followed. The horse owner may also need some supplies. Some owners may prefer to leave the shoe pulling to the farrier working at the vet clinic.

3. Owner: Make an appointment for the horse to be re-shod after the Hallmarq MRI is completed; this can be done at the vet clinic if the farrier is accustomed to working there or makes arrangements in advance. If a diagnosis is expected that might affect the shoeing, delay the re-shoeing in expectation of changes to be made.

4. Owner: Consider the use of padded boots like Soft-Ride Equine Comfort Boots during transport to and from the clinic if the horse is sore without shoes. At the very least, cover the feet with vet-wrap or duct tape to keep them clean. If the horse is traveling to the vet hospital, the feet with be cleaned again but remove any caked-on mud and debris and comb out any feathers and the mane and tail to make sure no metal is hidden in any of the horse's hair.

5. Owner: Do not use hoof polish, gels, sealers or any topical medications on the horse’s legs for 24 hours before the scheduled appointment. 

6. Owner: Don’t clip the pasterns unless directed to do so by the veterinarian or Hallmarq MRI technician. The vet clinic staff will usually clip any hair that is in the way.

7. Clinic: Clean the shoes with a wire brush and rinse under running water to remove any dirt and manure. Store them in a plastic zipper-top bag and mark them with the horse’s and/or owner’s name. Sometimes a veterinarian or consulting farrier will ask to see the shoe that was removed from a lame foot to check how the horse “wore” the shoe. Always be careful to properly dispose of nails.

8. Owner: After the shoes are removed and the feet are clean is a good time to take record-keeping photographs of the horse’s feet.

9. Owner: A horse with its shoes newly removed may be a little sore so give plenty of time to load and unload from trailers. If using a commercial service to pick up the horse, make sure they are aware of this. Farriers: make sure that owners or trainers know that this mild soreness after unshoeing is a specific side effect and not part of the horse’s larger lameness issue. Depending on clinic policy and arrangements made in advance, owners should be prepared to receive a partially-unshod horse after the MRI is complete.

10. Clinic, owner, farrier: Education is critically important to the success of the horse’s MRI scan. Learning how to properly use farrier tools and which farrier procedures are considered Best Practices in the preparation of a horse for MRI scanning is a new area where we all have a lot to share and learn from each other.

A carefully unshod horse whose clinches were cut (not rasped) and whose nails were removed with a creased nail puller is a welcome sight to the farrier who will be re-shoeing the horse; if he or she needs to re-use the nail holes, the wall won't be rasped away and if the shoes are re-used, it is not likely to be twisted in the heels. (Gary Huston photo)

In this age of MRI, Hallmarq recognizes that farriers are both needed in this important first step in preparation of the horse for MRI, and that farriers will be involved throughout the process of caring for the horse during its rehabilitation from the lameness that the MRI should help diagnose. For this reason, Hallmarq Veterinary Imaging is dedicated to including farriers in education programs and studies.

Content and photos © 2011 Hoofcare Publishing

--------

Watch for more in the Hallmarq-sponsored article series on The Hoof Blog, and check their social media system and especially their info-deep web site for lots more information.

To learn more about Hallmarq Veterinary Imaging and standing MRI technology for horses:

• Become a fan  of the new Hallmarq Equine MRI Facebook page;

• Follow @HallmarqMRI on Twitter;

• Subscribe to the hallmarqvetimaging channel on YouTube.com;

• Watch for a growing equine distal limb Hallmarq MRI image gallery on Flickr.com;

• Visit the Hallmarq.net web site. (Plan to spend some time there!)

Follow the Hoof Blog on Twitter: @HoofcareJournal

Join the Hoofcare + Lameness Facebook Page

Tweet

 

Hallmarq Veterinary Imaging Looks at the Statistics of Equine Foot Lameness: New Diagnostics Document More Precise Damage to the Feet of Sport Horses

The only “sure thing” number in the horse world is that most of the horses treated for lameness have four feet. Statistics quoted in the horse world range from the antiquated to the inflated, and professionals around the world are calling for more accountability of claims quoted in sales pitches and more quantification of the numbers that are quoted.

Once upon a time, someone somewhere said that 90 percent of equine lameness is in the foot, but does anyone know the original source of that quote? Would you say that is still true today? We can diagnose lameness a lot more precisely now than ever before.

One thing we do know: Hallmarq reports that, worldwide, almost 80% of lame horses referred for MRI at equine hospitals equipped with their MRI units have a problem located in the foot.

Where do you look for numbers when you need to prove a point? There is no “Fact Book” of equine lameness that collects statistics in one place. Instead, we all tend to trust certain authors or universities or studies. And everyone seems to have healthy skepticism for “the Internet”.

The deep digital flexor tendon (DDFT) is the most common site of damage in the foot identified by standing MRI scanning of sport horses. As you know, this tendon runs down the leg and attaches to the bottom of the coffin bone (P3). The three arrows added to this scan are directing the eye to the DDFT which, in this Irish horse, has a lesion that looks like a split. Normally tendon would be solid black. (Photo courtesy of Troytown Equine Hospital, Co. Kildare, Ireland.)

But it’s not all black and white, as two recent studies pointed out. In 2004, England’s Sue Dyson FRCVS reviewed 199 foot lameness cases at the Animal Health Trust. These cases had been evaluated by magnetic resonance imaging (MRI) and her analysis of the data showed that 33 percent had deep digital flexor tendonitis and a total of 60 percent of cases had some form of abnormality of the deep digital flexor tendon (DDFT). Desmitis of a collateral ligament of the coffin joint was found on 15 percent of the MRIs; it should be noted that Dyson’s practice is heavy on referral sport horses.

A high percentage of lame horses in both Great Britain and the United States have been found to have damage to the deep digital flexor tendon within the foot when standing MRI scans were analyzed.

On the US side of the Atlantic, Rick Mitchell DVM of Fairfield Equine Associates in Connecticut did a similar review. He looked at the results of standing MRI in 98 American jumping and dressage horses with foot pain.

Mitchell found the most common defect in the lame American sport horses to be navicular bone lesions, which were seen in the Hallmarq MRI scans of 77 percent of the horses examined. But 64 percent of Mitchell’s horses had deep digital flexor tendon damage in the foot, as seen on their MRIs. Coffin joint collateral ligament damage was much less common in Mitchell’s group than in Dyson’s.

But the glaring damage to the tendon is a critical warning sign to sport horse owners and trainers on both sides of the Atlantic.

Ten years earlier, diagnosing damage to the tendon in the foot was almost impossible. Now, Dyson and Mitchell can even break down the tendon damage into types of injuries.

Dr Laurie Goodrich of Colorado State University College of Veterinary Medicine sums up the need for MRI when diagnosing horses with foot pain: “Of horses with caudal heel pain, 60 to 70 percent have soft tissue injuries that we won’t see with radiographs because they only determine bone structure.”

New imaging modalities like MRI are making earlier and more precise diagnoses possible; another number we like: information gleaned from images obtained via standing MRI resulted in a diagnosis in almost 90 percent of the cases referred, according to Hallmarq's data analysis of cases.

So, when you quote numbers in the equine lameness world, also mention your source, the year and the type of horses that were tallied. If the study covered a specific type of horses and if the study was conducted since the advent of diagnostic imaging like MRI, it may make your numbers mean a lot more. And someone else may end up quoting you.

To learn more:

The largest and most accessible body of quotable statistics is the U.S. Department of Agriculture’s National Animal Health Monitoring System (NAHMS) “Equine ’98 Study”, which collected facts and figures on the health of horses on farms and ranches in 28 states. This was amended by updates in 2000 and 2005.

USDA, 2000. Lameness and Laminitis in U.S. Horses. USDA:APHIS:VS, CEAH, National Animal Health Monitoring System. Fort Collins, CO. Link to free download: http://www.aphis.usda.gov/animal_health/nahms/equine/downloads/equine98/Equine98_dr_Lameness.pdf

Dyson, Murray. Lameness associated with foot pain: results of magnetic resonance imaging in 199 horses (January 2001- December 2003) and response to treatment. Equine Vet Journal, 2004

Mitchell, Edwards, et al. Standing MRI Lesions Identified in Jumping and Dressage Horses with Lameness Isolated to the Foot, AAEP Proceedings, 2006.

--------

Watch for more in the Hallmarq-sponsored article series on The Hoof Blog, and check their social media system and especially their info-deep web site for lots more information.

To learn more about Hallmarq Veterinary Imaging and standing MRI technology for horses:

• Become a fan  of the new Hallmarq Equine MRI Facebook page;

• Follow @HallmarqMRI on Twitter;

• Subscribe to the hallmarqvetimaging channel on YouTube.com;

• Watch for a growing equine distal limb Hallmarq MRI image gallery on Flickr.com;

• Visit the Hallmarq.net web site. (Plan to spend some time there!)

Tweet

Hallmarq Veterinary Imaging Presents Dr Sue Dyson's Patient, A Showjumper Who Wanted to Stay on the Left Lead

Sue Dyson, FRCVS, is Senior Orthopaedic Clinician in the Centre for Equine Studies at the Animal Health Trust in Newmarket, England. The Animal Health Trust (AHT) operates a referral clinic for cases of lameness in sport horses, which is Dyson's specialty. AHT has advanced diagnostic imaging capabilities that are usually not available in equine veterinary hospitals.

Dr Sue Dyson of the Animal Health Trust is Newmarket, England performs systematic lameness exams on horses referred to the clinic for diagnosis or treatment. (Sue Dyson/Hoofcare Publishing image)

Imagine Sue Dyson examining Thomas, a five-year-old warmblood, who competes in low-level showjumping.

Thomas was referred to the Animal Health Trust because he was reluctant to land from a fence with the right forelimb leading. He had become awkward turning to the left and sometimes felt "pottery" (unlevel or unstable) in front. Thomas's vet had detected some swelling in the region of the left front foot's coffin joint, just above the coronary band. He was sound on a straight line but on a circle he showed left forelimb lameness on the left rein, which was worse on a firm surface that a soft one.

Nerve blocks were used to desensitize the back of the foot and this eliminated the left forelimb lameness. On a separate occasion, an injection of a local anesthetic into the coffin joint also made Thomas sound.

The impar ligament of the navicular bone is known as the Distal Sesamoidean Impar Ligament or DSIL. It anchors the navicular bone by connecting it to the coffin bone (P3). This ligament is very deep inside the foot and is not visible on a radiograph. (HC Biovision plastination image, uesd with permission)

X-rays of the foot were taken, but the vet saw no abnormalities. The vet explained that although primary injuries of the coffin joint can occur, a positive response to nerve-blocking did not rule out the possibility of injury to one of the other related structures.

A treatment plan devised by the horse's regular vet directed that Thomas’s coffin joint was treated with an injection of corticosteroids and hyaluronan, which made him sound within a few days and able to resume full work. He continued to progress well for about six weeks but clinical signs recurred. Never blocks were repeated and yielded similar results.

This MRI shows what a normal, undamaged DSIL looks like. It appears like a solid bank of white leading from the navicular bone to the inside of the coffin bone. The veterinarian interpreting the MRI would hope to see the DSIL looking the one in this image. (Hallmarq reference image)

The vet examined the collateral ligaments of the coffin joint, just above the coronary band, and could see no abnormalities. It was therefore suggested that an MRI scan should be carried out to try to establish a more definitive diagnosis. MRI often identifies injuries which are invisible when using other techniques such as x-rays or ultrasound, particularly when the problem is in the foot.

The MRI scan, performed at the Animal Health Trust, revealed that Thomas had sustained an avulsion fracture—an injury to the bone in a place where a tendon or ligament attaches to it—at one side of the attachment of the distal sesamoidean impar ligament to the pedal (coffin) bone. Clearly this was a problem that was going to require rest before Thomas would happily swap leads again.

Damaged DSIL: Deciding to look into the foot in search of a root cause of the lameness was delayed for months with this horse, while the vet treated what might be the horse's problem. This type of injury is relatively rare but can be diagnosed through advanced imaging. The MRI showed that the foot was damaged in the region of the distal sesamoidean impar ligament (DSIL) in the navicular zone. Compare this reference image with the other images of the DSIL in this blog. (Image courtesy of Dr Martinelli, California Equine Orthopedics)

Thomas's case study is a sponsored blog post in cooperation with Hallmarq Veterinary Imaging.

Watch for more in the Hallmarq-sponsored article series on The Hoof Blog, and check their social media system and especially their info-deep web site for lots more information.

To learn more about Hallmarq Veterinary Imaging and standing MRI technology for horses:

• Become a fan  of the new Hallmarq Equine MRI Facebook page;
• Follow @HallmarqMRI on Twitter;
• Subscribe to the hallmarqvetimaging channel on YouTube.com;
• Watch for a growing equine distal limb Hallmarq MRI image gallery on Flickr.com;
• Visit the Hallmarq.net web site. (Plan to spend some time there!)


MRI images used in this article were provided by Hallmarq as examples and are not the actual radiographs from Thomas's file.

This case study originally was written for an article on lameness in Horse and Hound Magazine.

Follow the Hoof Blog on Twitter: @HoofcareJournal

Join the Hoofcare + Lameness Facebook Page

Tweet