74 • April 2006 • WESTERN HORSE REVIEW

When it comes to front endlameness, there are two wordscertain to fill any horseowner with dread: naviculardisease. Such apprehension is

understandable. Until recently, a diagnosisof navicular disease meant chronic lameness,loss of usefulness, and expensive, specialshoeing that might help for a while – ornot at all. Owners trying to understand thecondition faced a labyrinth of conflictinginformation, making it difficult to knowwhat treatment and prevention strategieswere best. Ultimately, a horse withnavicular disease could be expected todeteriorate to a point where euthanasiawould be the only option.

Fortunately, recent advances in theunderstanding and application of correcthoof biomechanics are raising the possibilitythat many previously doomed horses may berehabilitated to a comfortable and useful life.In addition, recent research – and the re-examination of older research – is sheddingnew light on this condition. Though there isstill much to learn, many now believe thatthe lives of a significant number of navicularhorses can and will be saved if horse ownerscan get a clearer understanding of naviculardisease, and the new treatment and preven-tion options available to them.

DEFINING NAVICULAR DISEASEPeople often hear the terms “navicular

disease” and “navicular syndrome” usedinterchangeably, but they in fact havedifferent implications. Navicular disease hastraditionally referred to degenerative changesin the navicular bone that have beenconfirmed by radiography (X-rays). Horseswith radiographic evidence of naviculardisease may or may not demonstrate lame-ness – a fact that remains a source of greatconfusion. As for the clinical symptoms,they include:• chronic, progressive lameness in one or

both forelimbs• short or shuffling gaits, often with a

toe-first landing• sensitivity to hoof testers on the central

third of the frog• relief from pain when a nerve block is

applied to the palmar digital nerve• frequent shifting of body weight when

resting• resting the affected foot on the toe

(“pointing”)

Adding to the confusion surroundingnavicular disease, horses may exhibit someor all of the clinical symptoms, yet show noradiographic evidence of the problem. Thisis the scenario often referred to as “navicularsyndrome.” Many researchers, veterinariansand farriers, however, would prefer to see thisphrase dropped from the horseman’s lexicon.As renowned veterinary researcher andauthor of The Lame Horse, James R. Rooney,DVM, states: “The term ‘navicular syndrome’is both a misnomer and misleading. What isbeing said is that there is pain in the foot andthe speaker does not know the cause or siteof the damage.”

NEW RESEARCHThose who take issue with such vague-

ness will no doubt be pleased that recentclinical studies using magnetic resonanceimaging (MR) have provided veterinarianswith a technique to diagnose naviculardisease more precisely than ever before. Thisis because MR provides extremely detailedimages of soft tissue structures, such as

NEW THOUGHTS ON

NAVICULARSYNDROME

The extensivedevastation caused

by navicular givesrise to powerful

new studydevelopments.

BY SUSAN KAUFFMANN

Recent research and advances in understanding the hoofoffers hope for owners with horses suffering from navicular.

www.westernhorsereview.com • April 2006 • 75

ligaments and tendons, that could notpreviously be seen with other imagingtechniques, as well as giving much moredetailed images of bones. In a paperpresented to the American Association ofEquine Practitioners, researchers R. K.Schneider, P. R. Gavin and R.L. Tucker ofWashington State University writes: “MRhas added to our knowledge of naviculardisease, in large part, because for the firsttime we can see into the horse’s foot.”Though new studies like this cannot betaken as definitive, the conclusions of theWSU team have received a great deal ofinterest from scientists and equinepractitioners.

The WSU MR studies demonstrated thatthere are changes in the soft tissues thatoccur in association with navicular diseaselong before anything could be seen withconventional radiography, and they alsodetected bone abnormalities in cases whereconventional radiographs were normal.Furthermore, their observations stronglysupport what many equine practitionershave long suspected – that there are variousproblems in the foot that could cause clinicalsigns similar to those seen with truenavicular disease. As Dr. Rooney says,“Navicular disease is grossly over diagnosed.”However, that is likely to change as the newMR technique becomes more widely used.

The problems WSU researchers distinguished from navicular disease wereinflammation of the ligaments and deepdigital flexor tendinitis, both of which canproduce symptoms identical to naviculardisease and would likely be diagnosed as suchwithout the use of MR. The researchers onlydiagnosed navicular disease if they foundexcessive fluid in the navicular bone, whichis not present in normal horses. They state:“Unlike radiographic changes, which for themost part do not correlate with clinical signs,fluid in the bone on MR was observed tocorrelate with clinical signs. The most fluidand the most obvious abnormalities were inthe lamest leg.”

The important findings of the WSUteam have also led to changes in thetreatment of horses with navicular disease, aswell as those horses that were previouslyincorrectly diagnosed with the condition. Asthe researchers state: “Horses with DDFtendinitis have increased options fortreatment that have not previously beenused or have not been routinely recom-mended for horses with navicular disease.”Specifically, the researchers have found thathorses with DDF tendinitis near thenavicular bone improve when anti-inflam-matory medications are injected into thedigital flexor tendon sheath. Being able todifferentiate inflammatory problems fromnavicular disease also helps determinewhether a horse should be rested from work

or not. Rest is not traditionally recom-mended for horses with navicular disease,but may benefit horses with soft tissueinflammation. In addition, the ability to pinpoint what and where abnormalities arepresent in horses with navicular disease canhelp veterinarians decide which horses arethe best candidates for other treatmentprotocols.

THE CAUSE: A NEW (AND NOT NEW!)THEORY

Most experts feel that there are probablya number of factors that can lead tonavicular disease. However, one theory isgaining ground as a result of new researchand the fact that some hoofcare practitionersclaim that putting this theory into practicecan save the lives of horses that wouldpreviously have been put down or at leastretired because of navicular disease. Ironi-cally, this theory is not new, but has beenlargely overlooked until recently. First putforward years ago by Rooney, the theorysuggests that the unnatural toe first landingseen in many domestic horses – and theunnatural forces, rocking and vibration thatresult – is the primary cause of naviculardisease, not the other way around, as haslong been argued.

In other research involving post mortemexaminations of literally thousands of horses,Rooney demonstrated that it is not, aswidely believed, the navicular bone whichbecomes damaged first and then damages thedeep flexor tendon by rubbing on it. In fact,what he found was that damage occurs firstto the fibrocartilage (a matrix of cells andcollagen fibers) on the surface of thenavicular bone and to the fibrocartilage inthe deep flexor tendon; then the deep flexortendon itself; and finally, the navicular bone.Damage to the fibrocartilage in the deepflexor tendon and on the surface of thenavicular bone was always present if thebone was damaged, but Rooney found notone case in which there was navicular bonedamage without deep flexor tendon damage,which he would have found if bone damagewas the first thing to occur.

His conclusions about both the toe firstlanding and the order in which damageoccurs were strongly supported by anotherexperiment he conducted. He took thehealthy legs of dead horses and put them ina testing device that simulated a toe-firstlanding. Tellingly, those legs developedfibrocartilage damage identical to thedamage he had found to be the first evidenceof navicular disease in his post-mortemexaminations.

Why, exactly, the toe first landing is soharmful is perhaps best explained by PeteRamey, a highly respected leader, author andinstructor in barefoot hoofcare. Ramey says,“During normal, heel first movement, the

deep flexor tendon is quickly tightened bythe descending fetlock joint. At the sametime, the coffin joint is rotating forwardtoward breakover, and is loosening the deepflexor. In a toe first landing, however, thedescending fetlock is still tightening thetendon just after impact, but after impact,the heel rocks down, tightening the tendonsimultaneously. Understand that in a heelfirst landing we have one pulley tighteningas the other is releasing tension, but with atoe first landing, both pulleys are tighteningat the same time. Far greater force is directedto the navicular pulley than was everintended by nature. This is a very big differ-ence, adding greatly to the force applied tothe tendon and navicular bone. Greaterforce means greater friction, and the con-tinued repeat of this insult causes damage tothe region. These are major findings that Dr.Rooney has known and documented foryears.”

Unfortunately, Rooney’s work did notinitially receive widespread recognition itdeserved, most likely because the evidencehe presented demanded a radical re-examination of hoof care and veterinarypractices that few were prepared to under-take. As Ramey says, “Dr. Rooney provedand published that it was actually the un-natural toe first movement (usually causedby avoiding heel pain) that causes navicularremodeling; not the other way around asmost professionals thought. Understandably,Dr. Rooney is one of the most frustratedpeople I know of. Thousands of navicularhorses have been needlessly destroyed sincehis groundbreaking research. He was just 40years ahead of his time.”

That is all set to change, however, asother researchers and hoof care professionalslike Ramey are now presenting evidencethat supports Rooney’s work. Robert M.Bowker, VMD, PhD, of the ground breakingEquine Foot Laboratory at Michigan StateUniversity, agrees with Rooney’s assertions

coffin bone

navicular bone nerves to navicular bone

short pastern bone

common digital extensor tendon

deep digital flexor tendon

sesamoidean ligament

AN INSIDE LOOK

continued on page 76

76 • April 2006 • WESTERN HORSE REVIEW

about the damage caused by toe first landing,plus his own work highlights why suchunnatural landing happens, and what we cando about it. He has shown that horses haveinternal structures in the back part of thefoot that under natural conditions, continueto develop from birth through the first fewyears of the horse’s life. These structures,known as the lateral cartilages and thedigital cushion, are soft, thin and incompletein the newborn foal, but become key to thesupport, protection and overall function ofthe foot as they become thicker and stronger.

Unfortunately, current shoeing andhorsekeeping practices most often preventthe development of these structures, leavingour full grown horses with “baby” feet thatare extremely vulnerable to pain andlameness, particularly in the back part of thefoot. It is this unnatural and unnecessarysensitivity that leads to toe first landing –and too often, to navicular disease. AsRamey explains, “The back of the foot issupposed to be a solid, but flexible landingzone that can slam into any terrain like thehooves of a wild horse. It often hurts ourdomestic horses to run a hoof pick along thefrogs! This should scare us, but we’ve learnedto cope with this by shoeing the younghorse, lifting the frog off the ground andraising the heels. This lifts the sensitivestructures off the ground and makes thehorse feel better, but ensures the hoof willnever develop into something the horse canuse to dissipate impact energy like it wassupposed to. The horse will always be forcedto absorb energy impact with the rigid frontof the foot.”

THE TREATMENT IS IN THE TRIMFortunately, Dr. Bowker has shown that

even adult horses can develop the internalstructures of the foot to a great extent. Inorder for this to happen, however, it isabsolutely necessary to get the foot back tothe form and function that nature intended.Bowker summarizes this by stating: “If youkeep the toe short between the frog apex andthe hoof wall, keep the frog and bars on theground, leave the dirt in the foot [whichprovides natural support; manure should beremoved], plus get the horses out andmoving, you’ll have a healthy foot most ofthe time.” Bowker, Ramey and othersemphasize that it is this trim that makes thegreatest difference, whether you shoe thehorse or not.

For those interested in a bit more detail,Ramey adds, “The sole should not betrimmed except to sometimes exfoliateshedding or false sole. There should beenough sole depth to lift the collateralgrooves (beside the frog) about an inch offthe ground. The walls should be kept 1/16thinch longer than the sole and finished witha large bevel or ‘mustang roll.’ Routine frogtrimming should be avoided. It should be leftto callus, like the sole. If there is wall flare,breakover should be set exactly where itwould be if there were well connected walls.

“The hardest and most important part isachieving heel first landing and thus the frogpressure required to finish developing theinner structures. However, if you leave thefrog on the ground of a standing navicularhorse and the inner structures are weak andundeveloped, the frog may be so sensitivethat the horse ‘tiptoes’ in motion. This will

get you nowhere. Often we have to leave theheels a little longer for a few months. Asthey sink into footing, they reduce thepressure to the frog; often to a level the horsecan and will bear. This reduced pressureallows us to start making progress withdigital cushion development. Riding inboots with foam insoles dramatically speedsup this process.”

Ramey calls hoof boots with foaminserts “the most magical tools fornavicular horses.” He says, “I have beenable to find a boot and pad combinationthat makes navicular horses – yes, eventhose with confirmed bone remodeling –comfortable enough to ride. When you getthe trim and the pad combination right,the horse will stride out and load the footcorrectly on the second step. Continuedexercise in the pads develops the innerstructures rapidly, and usually, the pads andboots are soon no longer necessary.” Hepoints out that during the initial phase, thehorse is by no means healed, “but it cannow very comfortably receive thethousands of ‘pressure and release’ impactsit will need to develop the inner structurean adult horse is supposed to have. That’sthe difference between doing this withboots and foam pads versus any kind ofrigid supports that can only providepressure, but no release.” Ramey makes noclaim to being able to reverse bonepathology, just the cause of the pathologyand most of the pain. “The main point,” hesays, “is that we can get these horses happyand back to work – and we can darn sureprevent the problem in the first place.”

One dramatic success Ramey has had wasa vet-diagnosed, radiographically confirmednavicular horse that also had a significant P3rotation and sinking due to founder. “Theprevious owner tried many types oforthopedic shoeing by several farriers, noneof which had helped. They drove over 600miles to see me, so I was especially glad thatthe horse became sound within a month ofthe first trim, and three years later, is stillsound and working for a living.”

Another well documented, recentsuccess is Joey, a horse in the HoustonMounted Patrol that had been diagnosedwith navicular disease by a leadinguniversity. As Greg Sokoloski, an officer andtrainer with the unit recalls, “Joey was thevery best horse we had, so we were willing todo whatever was necessary to help him. Butafter nearly ten months of the traditionalorthopedic shoeing, he just wasn’t gettingbetter. The last time we took him back to theuniversity, they said he was going to have tobe retired. I then asked the vets there abouttrying a barefoot trim, as I had heard thatcould be helpful in such situations, but theysaid that going barefoot would just make him worse.”

Owners who decide to try the barefoot/boot/pad approach should be sure they havecompetent help. Barefoot rehabilitation and custom boot fitting are specific andseparate skills that are not covered in farrier education programs, and incorrector overly aggressive barefoot trimming can cause severe damage. Some

trimmers, for example, will say that extreme pain and abscesses are a normalpart of the healing process for a horse transitioning from shoes to barefoot,

but such problems result from incorrect, severe trimming and aredefinitely not necessary. The best bet is to find a professional through

the American Association of Hoof Care Practitioners (AANHCP)www.aanhcp.org, which offers a lengthy and intense certification

program with competent instructors such as Pete Ramey,Jaime Jackson and many others. Those seeking further

information may want to check out the followingwebsites:

- Pete Ramey: www.hoofrehab.com - Gene Ovnicek: www.hopeforsoundness.com

- James R. Rooney, DVM:www.horseshoes.com/farrierssites/sites/

rooney- WSU paper on MRI and

navicular: www.ivis.org/proceedings/AAEP/2003/schneider/ IVIS.pdf

A CAUTION:

continued from page 75

www.westernhorsereview.com • April 2006 • 77

But faced with losing Joey from the force,the administration gave Sokoloski permissionto try a barefoot trim on him. “We startedthe barefoot trim,” says Sokoloski, “and twoweeks later I was riding him. Another twoweeks later, we were riding him in one of thebiggest, most unruly protests we’ve had todeal with, and we were sure glad to havehim.” Joey was sound at that point, butSokoloski recognized that there was stillroom for improvement, so he took the horseto Pete Ramey. Says Ramey, “I trimmed thehorse in the clinic I was doing there andimmediately saw some improvement. Then Ifit the horse with boots and foam insoles,and people were cheering at the movement,but my wife Ivy and I could still see a bit ofhesitation in his gait. I added foam frog padsto the insoles, and the horse took off like hewas floating on air. Big, mean cops had tearsin their eyes the size of granny’s biscuits. Thehorse has been happily working ever since.”

Officer Sokoloski, who now has 22 bare-foot horses in his unit, is tremendouslygrateful that they were able to save Joey withbarefoot trimming and boots, but he remainsfrustrated by the experience. “It stuns methat we weren’t given this option by theveterinary professionals we consulted, at anypoint. People are told all the time that theirhorses with navicular are through, and thatjust doesn’t have to be the case. Correctbarefoot trimming makes a world ofdifference – and it shouldn’t be the last thingwe do. I wish everyone, horse owners andveterinarians alike, could learn from whatwe went through with Joey.”

Not everyone, however, is going to bewilling to try the barefoot and boots option,and that’s where the work of Gene Ovnicekcomes in. Ovnicek, a highly regarded MasterFarrier and developer of the Natural Balanceshoeing system, shares remarkably similarviews to Ramey when it comes to treatingnavicular disease. Both men assert that thebest way to treat and prevent the problem isto achieve correct, heel first landing throughphysiologically correct trimming based onthe hooves of wild horses. Ovnicek openlystates his belief that correct barefoot hoof-care is the healthiest option for almost allhorses, and that it is the preferable way totreat navicular disease. But, he does recog-nize that for some horses, that isn’t anoption, so he has developed a system of trim-ming and shoeing that he believes is thenext best thing.

Ovnicek says, “The way that Pete[Ramey] uses boots and pads is very similar towhat we do with our shoes and pads, whichare designed to provide protection, yet stillallow stimulation, and to promote a heel firstlanding and correct breakover. We first trimthe foot in the most efficient way to restorefunction, and what we add to it is only atemporary means to relieve the stresses and

strains so that the horses can be more com-fortable. The thing that is of paramountimportance in our work is that the wholeidea of the frog next to the ground and theother requirements of a healthy, functionalfoot are never left out of anything we do as atreatment modality.”

One of the requirements for healthyfunction that Ovnicek emphasizes is break-over. As he explains, “Most domestic horseshave only a moderately functional foot. Thisis because our whole perception of what weconsider a normal foot is actually a distortedfoot. The breakover is a big part of that, aswell as the lateral movements of the foot. Asfarriers, we were taught to promote a largefoundation under the horse – this was a good

thing. But most of what we should have beentalking about was producing good heelwidth. The rest of the foot is a lever that thehorse has to move over the top of. So, whatwe thought was proper, traditional hoofmaintenance was actually creating leveragesthat we’re now seeing as being a seriousproblem.”

Facilitating breakover is one of thereasons why Ovnicek believes that usingshoes as he does can sometimes help a navi-cular horse get comfortable more quicklythan being barefoot. “What we’ve found,especially with deep flexor lesions and imparligament pain, is that the breakover is goingto be a huge factor in relieving the strain toget them over the top of their foot,” saysOvnicek. “Now, if you can do that bare-

footed that’s great, but it is difficult to dobecause you’re limited as to how much youcan immediately reduce that breakover on abare foot.” Ovnicek aims to eventually tran-sition a horse out of shoes, but says, “Horseswith proper breakover, the frog on theground, and landing on the back of the footare going to have basically normal function,regardless of whether they are shod orunshod. The barefooted horse is going tohave better function, but the shod horse,especially if the foot is compacted with dirt,can be almost as good.”

Like Ramey, Ovnicek believes in theimportance of getting the navicular horsecomfortable and moving, and in his experi-ence, this should happen fairly quickly. “Theidea of a horse being unsound for a year oreven longer is, in my opinion and the opinionof many, unnecessary. We most often succeedin a very short period of time simply byputting these horses in a sound state andback to work, and allowing that to work inour favor. If a horse has badly distorted feet –heels curled under, the bars crushed in – justtrimming all of that distortion away andgetting them back on the ground gives horsestremendous relief right away.” Ovnicek addsthat this doesn’t mean the horses will neces-sarily be completely sound within the nexttwo to three months, because there may beother factors to consider, such as adhesionsof the tendons and ligaments that develop tocompensate for hoof distortion issues. “Still,”he says, “I can’t tell you how many timeswe’ve had horses come in that have beensuffering, sometimes for a year or two years,and instantly, those horses can go back to work and feel really good about whatthey’re doing.”

Though some may doubt the claims ofpractitioners such as Ovnicek and Ramey,the statements of these pioneers willundoubtedly be music to the ears of manyhorse owners searching for options after theirhorses are diagnosed with navicular disease.Ultimately, every owner must decide whattreatment options are best for their horses,but it is good to know that progress is beingmade in the baffling battle against naviculardisease.

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“They drove over 600 miles to see me, so I was especially glad that the

horse became sound within a month of the first

trim, and three years later, is still sound and working for a living.”