Lameness: General Articles

Understanding Lameness LAMENESS EXAMS: Evaluating the Lame Horse Learn to Recognize the Signs of Laminitis The Equine Foot Conformation Myths and Misunderstandings Lameness and Performance in the Sport Horse: Dressage Lameness and Performance in the Sport Horse: Show Jumping The Most Important Three Inches in Your Horse’s Career Protecting Your Horse's Legs With Proper Bandaging Techniques Lameness and Poor Performance in the Sport Horse: Eventing Applying Sweat Bandages To The Horse’s Leg

 

Understanding Lameness

by Doug Thal, DVM

          "Every horse owner should have a basic understanding of lameness." Doug Thal, DVM

Lameness accounts for more losses to the equine industry than any other condition. Hundreds of millions of dollars are lost annually due to lameness, more than twice the amount caused by colic.

Horses are affected by lameness in a variety of ways, ranging from subtle reduced performance to complete loss of mobility requiring euthanasia. Lameness can create significant pain and suffering for horses of all breeds and disciplines. Sadly, many horses are asked to perform when they are in pain because owners fail to recognize lameness.

Understanding the basics of lameness and working with an equine veterinarian who has experience with lameness can help horse owners in important ways, including:

* Purchasing horses that do not have current lameness and that are conformationally less likely to become lame (a strong argument for the pre-purchase exam)

* Recognizing conformational predispositions in their horses and managing for prevention and treatment

* Understanding that lameness, as well as training issues, may be the root cause of a horse¡¦s poor performance

* Insuring lameness problems are diagnosed early and treated promptly

In addition, understanding lameness and its relationship to basic form and function helps breeders make decisions that result in conformationally sound horses that are less likely to become lame.

CAUSES OF LAMENESS

Lameness can be caused by pain coming from any part of a limb that has nerve endings. This includes wounds to skin, connective tissue bruising, muscle pain, arthritis (joint inflammation), tendon sheath and bursal inflammation, tendon and ligament injury, and injuries to bone.

Lameness is often related to conformation. Horses with poor conformation are more likely to experience problems with joints, tendons, and ligaments than are horses of "normal" conformation. For example, angular limbs such as pigeon toe can set the stage for uneven mechanical forces that can lead to damage of joints and arthritis.

FORELIMB AND HINDLIMB LAMENESS

A high percentage of lameness in the forelimb occurs below the level of the fetlock. Upper limb lameness is not common in adult horses. It is more common in younger horses because developmental orthopedic disease is common in the upper limb in young horses.

Forelimb lameness is easier for most people to recognize and, generally, easier to diagnose than hind limb lameness. The massive musculature of the upper hind limb makes diagnosis much more difficult.

DIAGNOSIS

The lameness exam, a thorough, methodical exam, is the cornerstone of lameness diagnosis. It is a detailed veterinary procedure and includes the following steps.

(Note: Horse owners should be prepared to haul horses for the diagnosis of complex lameness problems. For many reasons, these exams are better performed in a clinic setting.)

1. Thorough history, including information on breed, age, and use; the date that lameness was first noticed; and how the injury occurred, if known.

2. Standing examination, beginning with observation at a distance to evaluate conformation and demeanor, then followed by an exam up close, including palpation of specific structures to identify any swelling, heat, pain, etc.

3. Exam in movement, primarily evaluating the lameness at the trot and usually performed on firm to hard, even footing. This often includes circles in both directions and may include inclines or specific patterns. Sometimes having a rider up is advantageous.

4. Flexion exams, stressing specific joints or regions of the limb for a specified time. The degree of lameness is assessed before flexion. The limb is then held in flexion, the horse trotted off, and the lameness compared. This helps identify the source of the lameness. As with many parts of the exam, flexion tests are interpreted in consideration of what is normal for that specific horse.

5. Hoof testers, using pressure placed on specific regions of the foot in search of a pain response. Once these steps are taken, the examiner should have identified which limb is lame and may have some idea about what part of the limb is causing the problem. If so, imaging (step 7) is likely to follow. If this has not yet been established, the exam may continue with nerve blocks (step 6).

6. Nerve blocks, used to methodically numb portions of the limb. A temporary "block" is produced with injection of a local anesthetic around specific nerves or into specific joints or other structures. The horse is assessed at the trot before the block. Then the area in question is numbed, and the horse is asked to trot off again. If there is no improvement, the process is continued on specific nerves, progressing up the limb until the lameness is lessened or abolished. This identifies the specific region of the pain

7. Diagnostic imaging can then be used to visualize the structures in the area. Imaging may include x-ray of bone, ultrasound of soft tissues, or less common modalities like magnetic resonance imaging (MRI), computerized axial tomography (CAT scan) and nuclear scintigraphy (two-dimensional imaging).

The complete lameness exam synthesizes the results of these parts to reach a conclusion about what kind of treatment may be helpful. Carried out and interpreted correctly, the lameness exam should provide an accurate diagnosis.

The usefulness of the lameness exam relies heavily on the expertise of the veterinarian. To be performed effectively, it requires a thorough understanding of anatomy, hands-on experience,

and a methodical approach. Because some of these component tests are subjective, a lameness exam is as much an art as it is a science.

THE FUTURE OF LAMENESS DIAGNOSIS

The MRI is now used more commonly in lameness diagnosis and is changing our understanding of lameness in the foot. MRI allows both soft tissue and bone to be examined in never-before-seen detail. MRI currently can image only the lower limb. This information can allow more targeted treatment and a better understanding of the prospect for recovery. Although this kind of new technology will add knowledge to the field, it will never be a substitute for a good lameness exam.

This article provided courtesy of The Horsemen's Voice, May 2006 issue.

keywords: causes, diagnosis . posted: 6/14/2006. Last updated: 6/14/2006.

 

LAMENESS EXAMS: Evaluating the Lame Horse                

Stress, strain or injury can take a toll on any horse, even one with no obvious conformation defects. When lameness occurs, you should contact your veterinarian promptly. A prompt examination can save you time, money and frustration by diagnosing and treating the problem immediately, possibly preventing further damage. The goal of such early examinations is to keep small problems from becoming big ones.

Lameness evaluations are also routine in most purchase examinations. When your veterinarian evaluates an animal you are considering for purchase, you may be forewarned about potential problems and should be able to make a more informed decision.

 

LAMENESS DEFINED

Traditionally, lameness has been defined as any alteration of the horse's gait. In addition, lameness can be manifest in such ways as a change in attitude or performance. These abnormalities can be caused by pain in the neck, withers, shoulders, back, loin, hips, legs or feet. Identifying the source of the problem is essential to proper treatment.

 

EXAMINATION PROCEDURES

Veterinarians have specific systems for performing examinations, depending on the reasons for the evaluation. However, essential features of a thorough examination include:

The medical history of the horse. The veterinarian asks the owner questions relating to past and present difficulties of the horse. He or she also inquires about exercise or work requirements and any other pertinent information.

A visual appraisal of the horse at rest. The veterinarian will study conformation, balance and weight-bearing, as well as ook for any evidence of injury or stress.

A thorough hands-on exam. The veterinarian palpates the horse, checking muscles, joints, bones and tendons for evidence of pain, heat, swelling or any other physical abnormalities.

Application of hoof testers to the feet. This instrument allows the veterinarian to apply pressure to the soles of the feet to check for undue sensitivity or pain. Many practitioners will concentrate on the front feet, as 70-80% of the horses weight will be supported by the front limbs.

Evaluation of the horse in motion. The veterinarian watches the horse walking and trotting. Gait evaluation on a flat, hard (concrete) surface usually yields the most. Observing the horse from the front, back and both side views, the veterinarian notes any deviations in gait (such as winging or paddling), failure to land squarely on all four feet and the unnatural shifting of weight from one limb to another. The horse also walks and trots in circles, on a longe line, in a round pen and under saddle. The veterinarian looks for signs, such as shortening of the stride, irregular foot placement, head bobbing, stiffness, weight shifting, etc.

Joint flexion tests. The veterinarian holds the horse's limbs in a flexed position and then releases the leg. As the horse trots away, the veterinarian watches for signs of pain, weight shifting or irregular movement. Flexing the joints in this manner may reveal problems not otherwise readily apparent.

 

DIAGNOSTIC TESTS

Diagnostic procedures are often necessary to isolate the specific location and cause of lameness. Lameness is best treated with a specific diagnosis. If your veterinarian has cause for concern based on initial examination, he or she may recommend further tests, including diagnostic nerve or joint blocks, radiographs, nuclear scanning, ultrasound, arthroscopy or examination of blood, synovial fluid and tissue samples.

Diagnostic nerve and joint blocks. These analgesic techniques are perhaps the most important tools used to identify the location of lameness. Working systematically, the veterinarian temporarily deadens sensation to specific segments of the limb, one joint at a time, until the lameness disappears. This procedure isolates the area of pain causing the lameness. Blocks can also help determine whether the condition is treatable.

Radiographs are useful in identifying damage or changes to bony tissues. They should be interpreted only by an experienced and knowledgeable veterinarian, since not all changes are cause for concern. Radiographs provide limited information about soft tissue, such as tendons, ligaments or structures inside the joints, which are often the source of lameness.

Scintigraphy (nuclear scanning). Radioisotopes injected intravenously into the horse are concentrated in areas of injury. These areas are scanned with a gamma camera, providing an image of the trouble site (horses will need to be quarantined for radioactivity after this procedure).

Ultrasound (sonography). This procedure uses ultrasonic waves to image internal structures.

Arthroscopy. This surgical procedure allows visual examination of the inside of a joint or tendon sheath. It requires general anesthesia but may be the only way to define the damage. Some diagnoses can only be made with arthroscopy. If deemed necessary, surgical treatment is often performed at the same time.

Blood, synovial (joint) fluid and tissue samples. These samples can be examined for infection or inflammation . Such examinations usually require laboratory testing.

 

AAEP LAMENESS SCALE

Because each horse has unique performance characteristics, evaluating lameness can be challenging. Experienced riders may detect minor alterations in gait before they are apparent to an observer. Lameness may appear as a subtle shortening of the stride, or the condition may be so severe that the horse will not bear weight on the affected limb.

With such extremes of lameness possible, a lameness grading system has been developed by the AAEP to aid both communication and record-keeping. The scale ranges from zero to five, with zero being no perceptible lameness, and five being most extreme. The AAEP guidelines explain the grading system this way:

0: Lameness not perceptible under any circumstances.

1: Lameness is difficult to observe and is not consistently apparent, regardless of circumstances (e.g. under saddle,

circling, inclines, hard surface, etc.).

2: Lameness is difficult to observe at a walk or when trotting in a straight line but consistently apparent under certain circumstances (e.g. weight-carrying, circling, inclines, hard surface, etc.).

3: Lameness is consistently observable at a trot under all circumstances.

4: Lameness is obvious at a walk.

5: Lameness produces minimal weight bearing in motion and/or at rest or a complete inability to move.

 

MORE ABOUT OBSERVING THE HORSE IN MOTION

The veterinarian should observe the horse on both soft and hard surfaces, since different types of lameness may become apparent with different footing. In addition, lameness may only be apparent when the horse is under saddle, or it may be manifest only at liberty or on a longe line when the horse can be evaluated without the influence of the rider.

A horse's walk and trot may be especially revealing. The slower gait of the walk makes it easier to observe slight deviations that aren't readily apparent at a faster pace. However, the trot is perhaps most useful for evaluating lameness because it is the simplest gait, consisting of a two-beat stride pattern, and because the horse's weight is distributed evenly between diagonal pairs of legs. In some cases the speed and concussion of a faster pace (i.e. canter, gallop) is needed to help demonstrate the lameness.

 

LAMENESS EVALUATIONS IN RELATION TO PURCHASE EXAMS

Evaluation for the presence of lameness should be part of every purchase evaluation. While it is impossible to predict a horse's actual performance, the veterinarian can provide information regarding lameness or potential lameness by evaluating conformation, movement, medical history, past performance and existing medical conditions. The extent of the exam will be determined by the buyer and veterinarian. Value, intended use and long-term goals may be factors in selecting certain exam procedures. For example, radiographs, sonograms and other diagnostic tests provide comprehensive pictures of the horse's

condition, but they also add to the exam's cost. Remember, your veterinarian cannot tell you whether to buy a horse or not, they can simply assist you in finding current or potential problems.

The most important question your veterinarian will ask is: What will you be doing with this horse? Your veterinarian will then weigh conformation, movement and medical considerations against the type and level of performance expected. A horse that is fine for a daily pleasure ride may not hold up under more strenuous activities.

 

LAMENESS EVALUATION

In the purchase lameness exam, the veterinarian will try to determine two things:

1) Is the horse lame at the present time, or are there existing conditions that deserve a closer look?

2) What is the likelihood that the horse will remain serviceable for its intended use? Age, health, expected level of activity, conformation and past use will be considered. The veterinarian will inform the owner of the relevant facts and risks, and the owner can then decide whether to purchase the horse.

 

LIMITATIONS OF PURCHASE EXAMS

It is important to remember that even a favorable report following a lameness exam does not guarantee there are no problems. Many factors can affect a horse's short- and long-term ability to perform. Factors in the lameness equation include many variables, such as:

Conformation Hoof care Use of protective leg gear Fitting and conditioning of the horse Degree and manner of training Type and level of performance Age Skill, balance and experience of the rider Type or condition of the ground on which the horse performs Disease or injury Genetic predisposition

Others

In order for your veterinarian to evaluate a horse fairly, the animal should be fit, conditioned and in training for its intended use. A horse that has been laid off for an extended time will be difficult to evaluate for lameness. One option may be to ask that the horse be returned to training and then re-examined after 30-60 days. Depending on the horse's value, such a request may be reasonable. Ask your veterinarian.

 

GOOD STEWARDSHIP

Lameness is a complicated condition, with many possible causes. Be a conscientious observer. If you suspect a problem, discontinue riding your horse and seek advice from your veterinarian promptly. By identifying even a minor lameness and acting swiftly to correct it, you will minimize the risk of injury to the horse and yourself, and you will be rewarded by better performance and a longer useful life from your horse.

For more information, contact your veterinarian.

American Association of Equine Practitioners4075 Iron Works Parkway, Lexington, KY 40511(859) 233-0147 

posted: 6/30/2005. Last updated: 7/5/2005.

 

Learn to Recognize the Signs of Laminitis

by Written by the AAEP

          Every day veterinarians across the country see hundreds of cases of laminitis, a painful disease that affects the feet of horses. Laminitis results from the disruption of blood flow to the sensitive and insensitive laminae within the foot, which secure the coffin bone to the hoof wall. While the exact mechanisms by which the feet are damaged remain a mystery, certain precipitating events can produce laminitis. Although laminitis occurs in the feet, the underlying cause is often a disturbance elsewhere in the horse’s body.

As a horse owner, it is important to recognize the signs of laminitis and seek veterinary help immediately. Signs of acute laminitis include the following:

· Lameness, especially when a horse is turning in circles; shifting lameness when standing

· Heat in the feet

· Increased digital pulse in the feet

· Pain in the toe region when pressure is applied with hoof testers

· Reluctant or hesitant gait, as if “walking on eggshells”

· A “sawhorse stance,” with the front feet stretched out in front to alleviate pressure on the toes and the hind feet “camped out” or positioned farther back than normal to bear more weight

Signs of chronic laminitis may include the following:

· Rings in hoof wall that become wider as they are followed from toe to heel

· Bruised soles or “stone bruises”

· Widened white line, commonly called “seedy toe,” with occurrence of blood pockets

and/or abscesses

· Dropped soles or flat feet

· Thick, “cresty” neck

· Dished hooves, which are the result of unequal rates of hoof growth

If you suspect laminitis, consider it a medical emergency and notify your veterinarian immediately. The sooner treatment begins, the better the chance for recovery. For information about laminitis, ask your equine veterinarian for the “Laminitis: Prevention and Treatment” brochure provided by the American Association of Equine Practitioners (AAEP) in association with Bayer Animal Health, an AAEP Educational Partner. Additional information can also be found on the AAEP’s horse health Web site, www.myHorseMatters.com.

The American Association of Equine Practitioners, headquartered in Lexington, Ky., was founded in 1954 as a non-profit organization dedicated to the health and welfare of the horse. Currently, AAEP reaches more than 5 million horse owners through its over 7,500 members worldwide and is actively involved in ethics issues, practice management, research and continuing education in the equine veterinary profession and horse industry.

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keywords: laminitis . posted: 12/19/2003. Last updated: 12/19/2003.

 

The Equine Foot

by Brad R. Jackman, DVM, MS, Diplomate ACVS

          Introduction

The foot of the horse is a very unique structure that undergoes a tremendous amount of strain and stress. The foot is the foundation of the horse and a structure is only as strong and stable as its foundation. Hence, the old adage “No Foot, No Horse.” The foot is the most common area of forelimb lameness because of the amount of stress to which the equine foot is exposed. Thus it is necessary to have knowledge of the foot, clinical conditions associated with the foot and ways to avoid and treat the more common foot problems.

Anatomy of the Foot

The foot structure is primarily composed of three bones: the third phalanx or coffin bone, the second phalanx or short pastern bone and the distal sesamoid or navicular bone. The short pastern and coffin bones support weight while the navicular bone serves as a fulcrum for the deep digital flexor tendon. The joint between the first and second phalanges is the proximal interphalangeal or pastern joint, and the joint between the second and third phalanges is the distal interphalangeal or coffin joint.

Besides the bones, there are numerous soft tissue structures within the hoof. The deep digital flexor tendon courses down the back of the limb and angles around the navicular bone to attach to the back of the coffin bone. The navicular bursa is a fluid-filled pouch that sits between the navicular bone and the deep digital flexor tendon and helps cushion and protect the bone and tendon. The navicular bone also has three ligaments attaching it to the second and third phalanges. There are two large collateral ligaments attaching the second and third phalanges. Any combination of these structures may be injured and a source of lameness.

There are also numerous external structures of the foot with which one should be familiar. The coronary band is where the skin and hair intersect with the hoof wall. The hoof wall grows from the coronary band at a rate of approximately 0.25 inches per month. On the bottom of the foot, there is the sole, frog, white line and bars. All of these structures are important and vital to the overall health of the equine foot.

Conformation

The relationship of how the foot is related to the limbs and how the limbs are related to the body determines the conformation of the horse. Genetics and growth will determine the limb conformation. However, the foot can be influenced throughout the horse’s life by trimming and shoeing. Horses will often toe-in and toe-out which will affect whether the horse travels straight or paddles out or wings in. Only when the horse is very young should attempts be made to correct these types of defects. Generally, the mature horse limb conformation should not be altered, as this is the angle with which the bones, tendons and ligaments have developed.

Foot conformation is extremely important in maintaining the health of the foot and the soundness of the horse. Ideally, the horse will have a large round front foot and a similar-sized more elongated hind foot. The sole needs to be concave, which allows for foot expansion and absorption of concussion each time the foot hits the ground. Normally the horse’s foot should land heel first and the heels of the foot subsequently expand. Thereafter, the pressure is moved from the walls of the foot to the frog, which further absorbs concussion as well as helps move blood through the foot and back up the leg.

There is no one ideal foot angle for the horse. The angle of the front hoof wall should parallel the pastern angle of the horse. Thus, if a horse has an upright shoulder and pastern angle then the hoof conformation needs to be upright. If the horse has a long sloping pastern, then the foot will also have a longer sloping angle. When there is an abrupt angle change in the pastern/foot angle, there will be abnormal forces exerted through the foot.

Shoeing

Proper foot care is the cornerstone of maintaining a sound horse. A good farrier is instrumental in keeping the horse’s feet balanced and well-supported. The farrier will trim the foot so that it is at a proper angle as well as balanced inside and outside. When a shoe is applied it needs to be the proper size and positioned so that the toe is rolled, since the horse cannot wear the toe down when protected by the shoe. Additionally, the shoe needs to be wider than the hoof in the heels, and the nails should not be placed back in the heels but only in the toe region. This allows for a good support structure for the heels of the foot to expand onto the shoe and therefore absorb concussion. Since the foundation of the horse is everything, a good farrier is a necessity and a tremendous asset.

Lameness Examination

Whenever a horse exhibits lameness, a thorough examination should be performed. More often than not, a good examination will be a beneficial investment, as it will lead to a more correct and faster diagnosis and usually a quicker return to soundness. The examination begins with a comprehensive physical examination, including palpation of the limbs, hoof tester examination and joint manipulation. The horse is then examined at motion to determine the severity of the lameness and which limb or limbs are affected. Localization of the lameness is performed with the use of local anesthetic deposited around nerves and/or within joints. Since the horse does not have muscle below the knee (carpus) or hock (tarsus), the nerves in the lower limbs only serve a sensory function and do not control motion. Therefore, local anesthetic can be used below these points to desensitize regions and determine if those locales are the source of the lameness. From the level of the knee or hock and above, local anesthetic is primarily only placed in joints as motion may be affected if deposited around nerves.

Once the lameness has been localized, the etiology of the lameness needs to be identified if possible. Many different diagnostics are available including nuclear scintigraphy, CT and MRI, but the most common are radiographs and ultrasound. It is critical that good, detailed, comprehensive radiographic studies be performed. When radiographing the foot, a minimum of five views should be taken to allow for a complete evaluation of all of the bony structures within the foot.

Conditions of the Foot

Navicular Disease/Syndrome

Problems with the navicular bone are common but are also overly feared. Conformation can lead to increased stress in the foot especially in the heel region and possibly predispose to the development of degenerative changes of the navicular bone. Horses with small feet and narrow heels do not absorb and distribute concussion as well and are predisposed to developing foot lameness. Additionally, a broken foot/pastern axis (especially if the toe is long and the heels are short) will place a tremendous amount of stress on the navicular region.

The clinical signs of navicular disease/syndrome include usually bilateral forelimb lameness, although one foot is usually more significantly affected. Often times the horse will exhibit pain during a hoof tester examination when the instruments are placed across the central one-third of the frog to the opposite heel. The lameness is localized to the heel region with local anesthetic. If needed, further information and localization of the lameness may be possible with the use of intra-articular anesthesia of the coffin joint and /or navicular bursa.

The cornerstone of treatment of navicular disease/syndrome is corrective shoeing. Despite the severity of radiographic signs, shoeing recommendations will be similar. The foot needs to be at an appropriate angle. Often that requires a wedge pad to make the foot more upright. The toe

should be shortened and rolled to hasten break-over, which is the point that the foot can come off the ground. The longer the foot stays on the ground and the horse’s body weight moves forward, the more pressure that will be applied to the heel region of the foot. In an effort to promote heel expansion, the shoe should extend behind the heels and be slightly wider than the heels. This type of shoeing should be performed every five to six weeks. It is the rare horse that can actually go eight weeks between shoeings even without lameness.

Further treatment includes blood flow-enhancers and anti-inflammatory medications. The most common medications used to stimulate blood flow are isoxsuprine and aspirin. It is not exactly known how isoxsuprine may enhance blood flow, but several studies have shown that approximately 50% of horses with heel pain will improve with its administration. Isoxsuprine is a very safe economical medication with little reason not to attempt its use. Aspirin is used similar to its use in heart disease human patients; it changes the way blood blows, making it easier to move through blood vessels. Phenylbutazone is the most common anti-inflammatory medication used. It is important that these horses become comfortable, move with a better stride and begin to land heel-first to enhance blood flow. Another means to deliver anti-inflammatory medications more directly is sterile injection into the coffin joint and/or navicular bursa. If possible, these horses are maintained in work if comfortable. They are at least encouraged to move around by turning out every day.

The prognosis of horses afflicted with navicular disease/syndrome is generally favorable. Most of these horses will return to full athletic use. Usually, corrective and appropriate shoeing will have to be continued for the horse’s career. Occasionally, the chronic use of isoxsuprine is necessary for long-term comfort. If the response to oral medications and corrective shoeing is insufficient, then synovial injections of hyaluronic acid and corticosteroid is used to direct a more potent anti-inflammatory locally. In those cases where conservative therapy is ineffective, the horse’s occupation can be changed or a palmar digital neurectomy can be performed. Neurectomies can be very successful; however, they do not change the disease process but only change the horse’s perception of the disease process. Additionally, the nerves usually will regrow and the procedure is only temporary; the odds are definitely favorable for the surgery to be successful for several years.

Fractured Navicular Bone

Although a fracture of the navicular bone can also be classified as navicular disease/syndrome, it is worth a separate mention as the clinical signs and treatment vary. Instead of a slowly increasing bilateral lameness, the horse with a fractured navicular bone will have an acute onset consistent lameness that may be severe. The lameness is a unilateral lameness. Most of these horses will want to land toe-first instead of heel-first.

If necessary, the lameness is localized to the heel region. Good-quality radiographs are needed to assess the presence and severity of the fracture. It is important to know that a line in the navicular bone is a fracture and not a separate center of ossification, called a bipartite navicular bone. The opposite forelimb navicular bone can also be radiographed for a comparison. If the same line is present in the opposite limb, then it is a bipartite navicular bone and not a fracture.

Treatment of a fractured navicular bone also requires corrective shoeing, but it differs from shoeing for navicular disease/syndrome. The heel is elevated using a wedge pad to make the foot a little more upright than normal to decrease the tension of the deep digital flexor tendon across the navicular bone. The toe is kept short and rolled. Usually a bar shoe with clips at the medial (inside) and lateral (outside) quarters is used to help stabilize the foot. The horse will be shod this way for usually at least four to six months. Stall rest is initially required, and once the horse appears comfortable on the foot then hand walking will be commenced. The duration of stall confinement is usually 60 to 90 days with another 60 to 90 days of small paddock

confinement. Additionally, phenylbutazone, isoxsuprine and aspirin are prescribed to reduce inflammation and promote blood flow respectively.

The prognosis with a fractured navicular bone is variable depending on the severity of the fracture but is relatively guarded for soundness. A significant amount of time is given to allow for healing. However, a palmar digital neurectomy is often necessary to help the horse maintain an athletic career.

Fractured Coffin Bone (Third Phalanx)

Fractures of the coffin bone are more common than fractures of the navicular bone. They can occur in multiple areas within the bone, and this will often determine the severity of clinical signs. In general, if the fracture is near the center of the bone and extends into the joint, then the horses will be more lame and the long-term prognosis may be reduced. Clinically, these horses also appear acutely with a unilateral foot lameness. The lameness is often significantly worse when the horse is circled in one direction versus the other. There may or may not be sensitivity with hoof testers in the region of the fracture.

The diagnosis is made with high-quality radiographs of the bone. Often, special oblique views are needed to identify the fracture. If the lameness is severe, then it is recommended that survey radiographs be taken of the suspected area prior to performing any peripheral nerve blocks as this may cause further damage to the fractured bone. Occasionally, slight hairline fractures may be very difficult if not impossible to observe on initial radiographs; radiographs are repeated in three to four weeks, as fractures will widen in the initial healing stages and they are more detectable radiographically at this stage.

The treatment of a fractured coffin bone is similar to a fractured navicular bone, but the duration is longer. A bar shoe with medial and lateral quarter clips is applied and often some type of impression material is placed between a pad and the sole of the hoof to give the coffin bone more generalized support. This special type of shoe is often used for one year. These horses are confined to a stall for 90 to 120 days with hand walking if comfortable. They are then allowed access to a small paddock for another 90 to 120 days. If they are doing well, they are then returned to a gradual exercise program. Phenylbutazone is administered as needed and occasionally the blood flow enhancers are used. A joint cartilage protectant medication is prescribed if the joint is involved. Rarely, if the fracture is into the joint and involves the midline of the coffin bone, a lag bone screw can be placed into the bone across the fracture line in an effort to enhance and expedite healing. This is a difficult operation with numerous possible complications and therefore is only used if absolutely necessary.

Most horses with fractures of the coffin bone have a good prognosis. Usually the fracture heals with a fibrous union and never quite disappears on the radiographs, but it is strong enough to withstand the normal stress. The only types of fractures with a poorer prognosis are the central fractures involving the joint. Occasionally these fractures will lead to secondary arthritis of the coffin joint and chronic lameness.

Laminitis (Founder)

The lamina in the equine foot connect the coffin bone to the inside of the hoof. There is sensitive lamina that covers the coffin bone that interlocks with the insensitive lamina on the inside of the hoof wall. There are numerous causes for the lamina to swell and therefore weaken the attachment of the coffin bone to the hoof wall. Generally, because of blood supply the most severely affected region is the lamina between the front edge of the coffin bone and the front hoof wall. As that area weakens, the deep digital flexor tendon continues to pull on the back of the coffin bone and usually rotation of the coffin bone is the end result. If the entire lamina becomes

affected, then the support for the coffin bone is compromised everywhere and the coffin bone sinks within the foot without rotation. Sinking is considerably more rare and has a significantly worse prognosis.

Most horses with laminitis will exhibit a relatively classic stance. They want to stand with their hind legs up underneath themselves and prefer to have their front feet out in front of them and land on their heels. They will be reluctant to move and will shuffle with quick steps when forced to move. The feet will usually feel hot and have an increased pulse because of the inflammation present. It may be difficult to pick up the feet, as the horse will not want to bear weight on an affected foot. If it is possible to apply hoof testers to the soles, there is usually a painful response in the toe region.

A tentative diagnosis is commonly made based on the clinical signs. To determine the presence and severity of laminitis, radiographs must be taken. It may be necessary to “block” the feet with local anesthetic to get the horse properly positioned for radiographs. If good-quality radiographs are taken, the degree of rotation or presence of sinking can be detected, as well as the thickness of the sole, length of toe and heel and if there are any gas pockets or gas lines present which signify an abscess.

Laminitis is a medical emergency that requires immediate and often aggressive therapy. A delay in treatment can significantly reduce the prognosis for the horse. Initially, if the horse is shod then the shoes are removed. Anti-inflammatories such as phenylbutazone and intravenous DMSO are given to try to aggressively decrease the laminar swelling present between the hard coffin bone and hoof wall. Blood flow-enhancers such as isoxsuprine, acepromazine and even topical nitroglycerine patches are often used. Excessive toe is removed and the angle of the foot should be appropriate for that horse. The sole is supported with either Styrofoam or cotton or a frog support pad. The horse should be kept in a clean, dry stall with adequate bedding to encourage lying down to decrease the force exerted through the front feet. If abscesses are present, then they must be addressed with drainage and care.

Once the initial laminitis becomes stabilized and the horse is more comfortable, then corrective trimming and shoeing will be instituted. This will usually take at least seven to 10 days. Any excess toe should be trimmed and rasped. The coffin bone will have to be repositioned to its normal angle by trimming down excess heel; however, this may need to be performed gradually as you don’t want to put excessive tension on the deep digital flexor tendon too quickly. Often, some type of frog support pad or pad with impression material is used to direct more support under the frog to share the load with the hoof wall.

If the degree of rotation is severe or the horse is refractory to medical treatment of laminitis with rotation, then surgery to reduce the pull of the deep digital flexor tendon may be indicated. The deep digital flexor tendon can be transected in the standing horse in the mid-cannon region. This will temporarily reduce the constant tension of the tendon on the coffin bone. The decrease in tendon pull will usually reduce the pain acutely. For longer-term success, every effort needs to be made to realign the coffin bone with corrective trimming and shoeing, as the tendon will heal over the next several months and tension will be reestablished.

The degree of rotation, severity of clinical signs and response to initial therapy will affect the prognosis. In general, the long-term prognosis with laminitis is guarded. Horse are prone to recur as there has been damage to the structure attaching the front coffin bone to the hoof wall and this attachment will never return to original strength. In severe cases, the blood supply may also be compromised to the point that repeated abscessation is a possibility. When undertaking the treatment of a severe laminitic case, the horse owner must be committed for prolonged treatment. It takes lots of patience, time and nursing care to return these horses to comfort, and it is unfair to the horse to begin therapy and then decrease that commitment to the therapy at a later date.

Additionally, an extremely capable farrier may be required for continued corrective shoeing for the life of the horse.

Summary

Lameness is the largest cause of economic loss in the equine industry. The most common location of forelimb lameness is the foot. There is a greater chance for a successful outcome if the lameness is addressed at its onset and a complete examination and workup is performed. Since the foot is the foundation of the horse, foot problems are best avoided if possible. That is best achieved with the horse having good limb and foot conformation to start, and then maintaining good conformation and support with good shoeing.

posted: 12/9/2003. Last updated: 2/12/2004.

 

Conformation Myths and Misunderstandings

by Dan Marks, VMD and AAEP member

          Dan Marks, VMD and AAEP member

 

INTRODUCTION

Most competition horses get too unsound, not too old. In theory, it is easier for a well-conformed horse to stay sound. However, many horses with conformation defects are able to perform quite well. It is important to know, for each occupation, which conformation faults are likely to cause problems because what is bad for one occupation may be acceptable or even desirable in another. It is also important to know that research contradicts some often repeated statements about conformation.

FOOT

For years, we have been taught that the normal angle of the front foot should be between 45-50 degrees. However, many competent observers over hundreds of years have found hoof angles to range from 47-57 degrees, with 54 degrees being the average. Research shows that lower angles:

influence the position of the foot on landing, causing the toe to land first, which is undesirable.

do not increase the length of stride of flight path of the foot as has been commonly illustrated.

increase tension in the deep digital flexor tendon, causing more compression of the navicular bone and decreasing circulation to the back of the foot

cause the heel to bear more weight

Many experts have pointed out that small feet, with their lack of hoof mass and sole depth, are an important factor in contributing to foot lameness. There has even been specific research to show that, above a certain amount of weight or force, there is significantly more "caudal hoof syndrome" (which includes navicular disease).

PASTERN

It is frequently stated that long, sloping pasterns in the front leg predispose the horse to strains of the suspensory ligament and superficial digital flexor tendon. While there is a certain appeal to this, it is the author’s experience that the opposite is more likely. That is, that long, upright pasterns in racehorses lead to a high incidence of suspensory injuries. Top dressage horses must have some length and slope to their pasterns otherwise the suspension and cadence required in their gait is not possible. Upright (especially short, upright) pasterns predispose to pastern joint disease, significant in jumpers and other performance horses.

SHOULDER

Almost all books on conformation mention the desirability of a sloping shoulder. However, poorly defined terms in this area make understanding what is meant by a sloping shoulder difficult. Some measure from the point of the shoulder to the start of the mane hair on the withers. Others measure the angle of the joint itself between the scapula and humerus. A third technique is to measure the slope of the spine of the scapula. These are three very different measurements and can lead to different results.

For example, most elite show jumpers, and many top thoroughbred racehorses have relatively upright scapulas but there shoulders are considered to be sloping when judged by a line from the point of the shoulder to the top of the withers. The combination of a long, upright scapula, a shoulder joint angle of about 105and a laid-back wither are ideal to provide the vertical propulsion from the front legs that is necessary for jumping big fences. While some have stated that an upright scapula leads to excessive front leg wear, stumbling and jarring gaits, this has not been the author’s experience.

HOCK

There are a great deal of unsupported statements about hock conformation. The author believes that a range of angulation , as viewed from the side, is compatible with superior racing

performance. An even wider range of hock angles is compatible with jumping and soundness in general.

Although hocks with an angle of less than 150(sickle-hocks) are more prone to disease of the lower hock joints and more likely to get a curb, many will be sound, especially if effectively managed. Extremely angulated racehorses may "run down" (abrade and bruise the ergot region).

Straight hocks (post-legged conformation), where the angle is over 170, are more prone to strain of the flexor tendon sheath (thoroughpin) and upper portion of the suspensory ligament. When accompanied by a long, sloping pastern, strain of the middle and lower portions of the suspensory ligament are more likely. Although the last condition is common in older broodmares, it can occur with middle-aged performance horses and can be career-ending.

The term "cow hocks" is used to describe a deformity where the horse stands with its feet wider than its hocks. It also used to describe a horse where the hocks are close together but the cannon bones are vertical. While this second conformation (slight "X-legged" or knock-kneed) is not a cause for concern in the author’s opinion, hocks that are bow-legged are unlikely to withstand serious collection. As collection (or speed) increase, the hind legs go more to the center line, accentuating stresses.

Bog spavin (swelling of one of the hock joints) is usually related to an osteochondrosis dissescans (OCD) lesion. A study showed that, overall, the inheritance for OCD in the hock was quite high. In a study of 39 stallions, offspring with OCD ranged from 0 to 69% in one stallion.

SUMMARY

Conformation is frequently referenced in vague generalities: how short is a short back? what angle makes a horse sickle-hocked? at what angle is a stifle considered straight? We have to try to define our terms better; make our measurements more consistent; and try to quantify or put numbers to, normal and abnormal anatomical structures whenever possible. An understanding of conformation may assist the owner, farrier and veterinarian in a number of way, but only if all involved are speaking the same language.

If we read some of the texts on conformation and totally adhered to their suggestions, we would buy few horses and certainly miss some very good ones. Anyone with modest information can fault a horse’s conformation. The smart horseman is the one who first, knows what a good one looks like and second, plays the percentages on the conformation defects.

 

 

posted: 6/18/2002. Last updated: 6/18/2002.

 

Lameness and Performance in the Sport Horse: Dressage

by Sue Dyson, FRCVS and AAEP member

         

Sue Dyson, FRCVS and AAEP member

 

THE SPORT

The Federation Equestre Internationale (FEI) dressage rules state that the object of dressage is the "harmonious development of the physique and ability of the horse." Through the levels of dressage training, the center of gravity of the horse and rider is placed further back by increasing the degree of flexion and loading of the hindlimbs while at the same time freeing the front end of the horse to create a more uphill set of movements. This can only be obtained by increasing the power of the hindlimbs, by synchrony in movement between the frontlimbs and the hindlimbs, and through the freedom of movement of the back.

The key to the training and development of a dressage horse from the lowest levels to International Grand Prix is gymnastic exercises that aim to strengthen the muscles and thereby avoid injury to joints and tendons associated with an increased workload. Lateral movements apply specific unique strains to different structures within the skeleton. In shoulder-in, half-pass, renvers, and travers the horse is evenly bent in his neck and body, but moves on more than two tracks. These movements create an unusual strain on the horse’s back and an additional twisting movement on the joints of the limb. The increased engagement of the hindlimbs developed through collected work allows for greater storage of elastic strain energy in the hock joints and pelvis which, via the increased lifting of the forehand, allows for high energy movements such as medium and extended trot.

Potential manifestations of a musculoskeletal disorder in the dressage horse include:

Reluctance to accept or go to the bit, shortening the neck, stiffness Not taking the contact evenly on the left and right sides Irregular rhythm in specific lateral movements, e.g. left shoulder-in and right half-pass Irregular rhythm in medium or extended trot Short steps behind in walk Uneven height of steps or lack of rhythm in piaffe and passage Inability to collect, stiffening the back, and not "sitting down" behind Loss of freedom and elasticity of movement

Late behind in flying changes or difficulties in changing from left to right compared to right to left, or vice versa

THE HORSE

The dressage horse must be naturally well balanced. The head and neck must be set on sufficiently high to facilitate working "uphill" and making easy contact with the bit. The shape of the withers region is important so that the saddle sits easily in the correct position. The dressage rider spends a lot of time sitting in the saddle, therefore correct weight distribution is critical.

Most dressage horses are broken at three or four years of age and begin competing in young-horse classes as five-year-olds. Medium classes are reached by the age of seven and many future Grand Prix dressage horses do their "small tour" at the ages of eight and nine. Once the dressage horse has reached Grand Prix level, the training predominantly involves repetition of movements, maintaining suppleness, and increasing physical power. It becomes obvious that they will rarely succumb to acute, stress-induced, traumatic injuries, but are more likely to develop repetitive, accumulative, subclinical injuries which may surface at irregular intervals. This means that, with the correct training and management, dressage horses can continue to compete at the highest level at an advanced age, often as old as 15 to 20 years.

Wear and tear lesions frequently occur due to a less than ideal joint and limb angulation, but many other factors influence the durability of the horse, including genetic predisposition and less than ideal management conditions prior to skeletal maturity. The main requirement must be the ability of the horse to balance itself at all paces, since imbalance and asynchrony in movement apply unusual strains on many structures.

TRAINING SURFACES

Dressage horses are predominantly trained on artificial surfaces with a high degree of cushion, providing a consistency in the training surface not paralleled in other equestrian sports. The standardization of working and competition surfaces unquestionably plays a huge role in the low occurrence of many acute orthopedic problems in the dressage horse. Some trainers, however, consider consistent working on ideal surfaces likely to "soften" the limb structures and recommend the horses be occasionally either jumped or hacked out on less-than-ideal surfaces to stimulate bone, joint, tendon, and ligament adaptation.

Arena maintenance is extremely important; drainage is an essential key to a good surface. Dead corners of deep sand predispose to momentary loss of balance and thus the development of lameness. Any sudden change of surface integrity may predispose to lameness. Young horses in particular work more easily and confidently on firmer artificial surfaces, where they can obtain a more confident grip and are less likely to fatigue.

TACK

The horse must be comfortable in its tack if it is going to work optimally. Dressage saddles are designed to position the rider with a deep seat and an extended leg position. The surface area over which the weight is distributed should be as large as possible to avoid pressure points. The use of gel pads and layers of saddlepads is not a substitute for good saddle fitting. The saddle must fit both the horse and the rider, and must position the rider appropriately in balance. The fit must be assessed with and without a rider. The shape of the horse’s back musculature may change as the horse develops muscular strength and power; therefore, a previously well-fitting saddle may become constricting. As the muscles over the withers and shoulders expand, a particular saddle may appear to fit correctly prior to working the horse, but be restrictive an hour later when the horse begins piaffe and passage movements.

Acceptance of the bit is crucial in the dressage horse. Horses vary considerably in the shape of the mouth and the sensitivity of the corners of the lips, bars, and tongue. There is also a huge variation in the thickness of the tongue between individuals. A slight crack in the corner of the mouth caused by an inappropriate bit can cause major problems with proper acceptance of the bit and the horse’s willingness to work straight. The horse may be very apprehensive of taking the bit, may take irregular steps, or be reluctant to bend properly. The presence of wolf teeth is frequently blamed for reluctance to accept the bit properly or irregularities in gait. Provided that a wolf tooth is immediately in front of the first upper cheek tooth and not mobile, it is rarely associated with pain. At upper levels, horses have to compete wearing a double bridle, i.e., the mouth has to accommodate both snaffle and curb bits. These vary hugely in size, shape, and design and selection of the most appropriate can be critical.

LAMENESS EXAMINATION

The most common causes of reduced performance or lameness in the dressage

horse include:

Inflammation (or tearing) of the top of the suspensory ligament ("high suspensory disease")

Suspensory branch injuries Degenerative joint disease of the hock Degenerative joint disease and inflammation of the front pastern Inflammation of the middle knee joint Degenerative joint disease and inflammation of the fetlock Inflammation of the digital flexor tendon sheath Stress fractures of the cannon bone Back pain

Examining the lame dressage horse does not differ in any great detail from examination of any other equine athlete. However, it frequently requires more time being spent observing the horse ridden, since many dressage horses only reproduce the perceived problem, often no more than a resistance, when ridden through certain movements or at medium or extended paces. This, however, does not mean that the horse should not be examined in hand, including walking and trotting on a straight line and lunging on both hard, non-slippery surfaces (such as gravel) and on artificial surfaces. Leading the horse on a circle at a trot tends to alter the horse’s stride. The horse does not have the freedom to move his neck and instead will "set" his head on the leader’s

hand. With subtle problems it is particularly important that the conditions, including the surface, remain consistent throughout the lameness investigation. It is difficult to start the investigation on one surface only to find that halfway through the nerve blocks the horse has to be assessed on a different surface.

In many cases, the usual rider has to be available in order to reproduce the described problem if this is not an overt lameness. If the rider is not in balance or sits crookedly, this can itself induce gait irregularities or lameness. Therefore, it may be preferable to use a good professional rider who is not the trainer of the horse to work the horse. It may require several days to determine definitively whether the problem is one of riding and/or training, or reflects a genuine lameness. However, it should be remembered that, in addition to less-than-good riders creating lameness, good riders may hide lameness. The latter may take place completely unintentionally and involve no more than a corrective change of point of balance of the rider though a corner, but enough that for a long time the problem may not be observable from the ground.

The veterinarian will not just focus on the limbs when watching the horse being ridden. It is important that he or she observe such changes as an increased lathering of the mouth, audible change in the rhythm of the stride or even absence of teeth grinding or grunting following a particular diagnostic test.

In many cases, the veterinarian will rely heavily on the observations of the rider during the lameness examination. This may involve the appreciation of a subtle change of gait or even just an impression of a stronger rhythm or less heavy contact on the bit following a nerve block to a limb. Many riders feel through their own body that the horse is working "crooked," i.e., not straight and in complete balance, and will be able to tell the veterinarian if this feeling has been altered by any of the diagnostic tests. It may be useful to alternate between lunging and ridden work, often going back to lunging with full tack after the horse has been ridden to see a possible difference in the gait after this exercise.

Another useful test is to ask the rider to deliberately ride "on the wrong diagonal," i.e., rising trot with the rider in the saddle when the inside forelimb is bearing weight. Both forelimb and hindlimb lamenesses and horses suffering from back pain, in particular, will alter when the weight-bearing diagonal (of the horse) is changed. The difference between the horse’s outline and attitude when changing between sitting and rising trot may also add valuable information.

If a diagnosis cannot be made because clinical signs are too subtle, or it is difficult to determine whether or not the presenting clinical problem is pain-related, it may be useful to work the horse while treating it with anti-inflammatory pain-killing medication such as phenylbutazone for two to three weeks. This may or may not "provide" a lame horse when medication is withdrawn and help to determine if a performance problem can be attributed to pain.

 

 

 

 

posted: 6/18/2002. Last updated: 6/18/2002.

 

Lameness and Performance in the Sport Horse: Show Jumping

by Sue Dyson, FRCVS and AAEP member

         

Sue Dyson, FRCVS and AAEP member

 

THE SPORT

The athletic demands placed upon the elite show jumper are huge. It must be able to jump large fences with precision, accuracy, and care, sometimes at speed. It must be supple and able to make sharp turns and jump from a virtual standstill, while also being able to jump almost from a gallop. It must have tremendous strength in the back and hindlimbs to be able to adjust stride length and jump from "deep" and bascule, with the capacity to jump large spread fences.

The majority of successful, modern, elite show jumpers are naturally well-balanced, loose-moving athletes. They are relatively large horses, most being between 1200 and 1500 pounds body weight. Unlike many other disciplines, there is a reasonable balance of males (geldings and stallions) and mares, although there does not appear to be any difference in susceptibility to injury. The majority of elite show jumpers are warmbloods that vary in their conformation, but are generally well-proportioned. The feet are a notable exception. The feet of warmblood horses are often not well-conformed or well-proportioned in size and shape relative to the horse’s body

weight. Thus this can be regarded as a conformational fault, sometimes compounded by poor foot trimming. Greater attention to foot balance may help to prevent some lameness.

The elite show jumper generally has a heavy competition schedule with little time for recovery from injury before it is next expected to compete. It also has to withstand traveling long distances between competitions and often confinement in relatively small stables, with little opportunity for turnout. Therefore, exercise is restricted to ridden work and handwalking. Since elite show jumpers travel so much, use of the same farrier becomes difficult, so the horse may be subjected to variable trimming and shoeing. Due to the intensity of competition, early identification of any potential problem is crucial; therefore, regular, comprehensive monitoring of the musculoskeletal system is recommended.

CHRONIC ONSET LAMENESS

The stresses placed on the hindlimb suspensory apparatus on take-off and the forelimb suspensory apparatus at landing are enormous. There is also immense torque placed on joints when making quick turns. Thus, there is the potential for subclinical lamenesses, causing low-grade intermittent or continuous pain, compromising performance without resulting in overt lameness. Nonetheless, some horses are able to perform very successfully despite low-grade overt lameness. Some problems that a horse can cope with adequately when performing at lower levels may become a problem when the horse is subjected to extreme demands on its athleticism.

Low-grade problems may first show up as a change in performance rather than overt lameness. Signs of a musculoskeletal disorder may include:

Not pushing evenly off both hind limbs, with the hindlimbs drifting to one side therefore not jumping squarely across a fence

Reluctance to turn Refusing to land with one forelimb leading Difficulty in making the distances in a combination fence Difficulties in alteration of stride length Reluctance to get deep into a fence, or a tendency to have rails down in such

circumstances Rushing fences Stopping (refusing) Changing legs behind in canter

Chronic lameness must be identified and controlled to: 1) enable a horse to pass mandatory veterinary inspections at international competitions, 2) optimize its performance and 3) reduce the risk of the development of secondary, acute problems.

ACUTE ONSET LAMENESS

There are many potential causes of acute onset lameness which are not unique to the show jumper, elite or otherwise. There are, however, a number of conditions which seem to occur with higher frequency in elite level show jumpers, compared to horses performing at lower levels. These include:

Inflammation of the accessory ligament of the deep digital flexor tendon in the forelimb Superficial digital flexor tendonitis in the forelimb Deep digital flexor tendonitis within the forelimb hoof capsule Inflammation of the suspensory ligament in the forelimb and less commonly the hindlimb Inflammation of either branch of the suspensory ligament in either the forelimb or

hindlimb Inflammation of the digital flexor tendon sheath

CLINICAL EXAM

Successful management of the elite show jumper requires knowledge of the individual, how it normally moves both in straight lines and in circles on both soft and hard surfaces, and how it responds to a variety of manipulative tests. It is essential for the veterinarian to have a good working relationship with not only the rider, but also the groom, who may have the greatest knowledge of any subtle changes in the horse’s action or behavior.

A comprehensive clinical examination should include careful palpation of the limbs and back for detection of areas of heat, pain or swelling, and muscle tension. The development of fluid swelling in the joints, even in the absence of overt lameness, should be regarded with suspicion. Flexion and twisting of joints should be performed to assess both mobility and the presence of pain.

A significant number of elite show jumpers exhibit some degree of shivering-type behavior in one or both hindlimbs (involuntary muscular movements of the limbs and tail). Frequently this does not appear to be associated with any compromise in performance, but it does complicate the evaluation of the response to flexion of the hindlimbs.

The horse should be evaluated moving freely in-hand on a hard surface and on the lunge on both the left and the right reins and on both soft and hard surfaces. The response to flexion of each limb should be assessed. In some instances, it is necessary to evaluate the horse while it is ridden, and if necessary, jumped, in order to detect a problem. It may also be necessary to rely on the feeling of the rider that the horse is "not right."

Local nerve blocks are invaluable techniques for isolation of the site(s) of pain, either to temporarily remove overt lameness or to improve performance. It is sometimes necessary to medicate a suspicious joint on a diagnostic basis, since a better effect may be achieved. Nuclear scintigraphic examination can be invaluable in identifying suspicious areas in cases of low-grade

poor performance, but due to the large variation in scintigraphic appearance between clinically normal horses, it is usually necessary to desensitize a suspicious region with a local nerve block to confirm that it is indeed a source of pain. Radiography and ultrasonography are essential components of the diagnostic toolbox as well.

MANAGEMENT FOR OPTIMAL PERFORMACE

The development of fluid swelling within a joint, pain on passive manipulation of a joint, or lameness after flexion are all indicators of possible significant problem which may merit treatment by judicious medication directly into the joint. While recognizing the potential benefits of intermittent medication of joints that have low-grade problems, it must always be understood that there are inherent risks; therefore, this should only be done when necessary. The joint should be evaluated radiographically in order to determine the presence of a pre-existing joint problem, or, if a recurrent problem, progression of any previously identified abnormality. However, not all radiographic abnormalities are necessarily of current clinical significance.

The back should be assessed carefully since it is very prone to low-grade muscular injury and bony abnormalities such as impingement of the tops of the vertebrae can cause recurrent low-grade discomfort in elite athletes. However, mild impingement can be present but not result in clinical signs; therefore, its significance should be assessed by clinical examination, response to local infusion of numbing solution and, if necessary, nuclear scintigraphy.

Attention should be paid to the way in which the horse is trimmed and shod to ensure correct foot balance and the most appropriate shape of shoe for the horse’s foot. Studs should be used with care, since, while providing extra traction, they can themselves unbalance the foot and concentrate forces delivered through the foot.

Finally, the horse should always be looked at as a whole rather than as separate bits in isolation. The show jumper, like other horses, requires variety in work pattern and time to relax. Keeping the mind sweet is just as important as keeping the body in good shape.

posted: 6/18/2002. Last updated: 6/18/2002.

 

The Most Important Three Inches in Your Horse’s Career

by Lydia Gray, D.V.M.

         

Lydia Gray, D.V.M.

Introduction

What makes one footing better than another? Is it possible to find a surface that maximizes your horse’s athletic potential while at the same time protects him from injury? And what can you as owner, trainer or rider do to bring out your horse’s best and maintain his soundness when faced with less than ideal footing?

Ideal footing varies with the sport, local climate, natural ground type and gradient, and location (indoors or outdoors). It is easier to choose a suitable surface for a single sport in an indoor arena than it is to cater to the needs of several different sports in an outdoor arena, where the unpredictable effects of the weather play a role. The capital investment and the practicalities of maintaining the surface on a day-to-day basis are also important. As a result, the end product is often a compromise between the ideal and the practical/affordable, which may not be in the best interest of the horse. In this article, how horses move will be taken into account with footing in order to help reduce the risk of performance-related injuries.

Equine Biomechanics

By studying equine biomechanics, or how horses move, researchers have been able to tell what part of the hoof or limb is undergoing stress during each phase of the stride. Although it seems that the more we uncover about gaits the more there is to uncover, fortunately much of what has been done in human biomechanics can be applied to horses.

For example, in people, the repeated shock of impact with the ground is responsible for the development of osteoarthritis (degenerative joint disease or DJD). Activities that involve running or jumping--in which there is an airborne phase--are much more damaging than walking or stepping--in which there is always at least one foot on the ground. This is why people tend to get fewer injuries when doing low impact aerobics. Similarly, the shock of impact of the hoof with the ground is the most important phase of the stride in relation to the development of DJD in the horse. A description of the chain of events that occurs as the hoof contacts the ground helps explain why this is so.

As the hoof approaches the ground, it is moving forward and downward. At the instant the hoof strikes the ground, it is rapidly slowed down. Although the hoof acts as the initial shock absorber for the skeletal system, this rapid "deceleration" sends a shock wave up the horse’s limb. As the shock wave travels up the limb, two specific types of tissue aid in its dispersion: bone and cartilage. While bone is a fairly efficient shock absorber, excessive impact shocks may lead to microfractures. Cartilage is an even more effective shock absorber than bone, but because it is present in such a thin layer in the joints it makes a relatively small contribution to reducing the shock impact. Repeated impacts, especially of great force, can lead to progressive and irreparable cartilage damage, eventually resulting in DJD.

Effects of Footing

Reducing impact shock, then, is one aspect of footing that should be considered when choosing or evaluating a work surface for performance horses. "Impact resistance" is the term used to describe the ability of footing to absorb impact energy. It affects primarily the hoof’s downward motion. Surfaces with high impact resistance (e.g. concrete) absorb little energy on impact and are associated with high impact shock. Surfaces with lower impact resistance (e.g. wood chips) absorb more energy on impact and result in lower impact shock.

It is useful to compare the physical characteristics of different surfaces in relation to their effect on the horse. Hard surfaces such as concrete, asphalt and hard soil have high impact resistance. Consequently, the limbs are rapidly decelerated after contact leading to high impact forces and considerable concussion. Because hard surfaces also do not allow the toe of the hoof to penetrate, there is great pressure applied to the navicular region. Therefore, hard surfaces are particularly damaging to horses with navicular problems.

Sand, on the other hand, has a somewhat lower impact resistance than hard soil. However, deep or dry sand can lead to injuries other than those caused by impact shock. In addition, the horse must use a greater muscular effort to overcome the tendency of sand to give way underfoot. The working heart rate can be up to 50% greater on deep or dry sand, which explains why sand is so tiring for horses to work on. Anyone who has run on a beach has experienced this phenomenon for themselves.

Characteristics of turf, including its impact resistance, depend on several factors, notably the moisture content of the soil. For example, as the soil dries out, the impact resistance increases. Although a high moisture content lowers the impact resistance, too much moisture allows slipping. Well-maintained turf provides excellent footing, but it is difficult to keep the turf in this condition. Deterioration in surface characteristics under conditions of drought or excess rainfall is a problem for turf arenas and tracks.

Conclusion

There are many more components of footing that affect your horse’s potential for performance (and potential for injury) than are presented here. The best suggestion for reducing the risk of acute and chronic injuries due to footing is to use common sense:

o Try to train on the same type of footing that you will be competing on. Abrupt changes in footing are one of the leading causes of injuries.

o Avoid inconsistent footing. Surfaces that have soft and hard spots, deep and shallow spots, or dry and slick spots can be dangerous.

o Make sure your horse is trained and conditioned for the job you are asking him to do. On the other hand, overtraining and overconditioning a horse can also lead to injuries as fatigue enters the picture.

o And finally, eliminate or reduce the effects of other causes of performance-related injuries such as shoeing; training, conditioning and competition schedules; conformation; and pre-existing conditions.

 

Resources

Your local veterinarian can be a great place to get started learning more about all the things discussed in this article. In addition, your local extension office will have information specific to your region; organizations representing your specific breed and discipline may have information specific to your sport. Footing companies are another excellent resource as are pamphlets and books such as "Under Foot" by the United States Dressage Federation and The Equine Arena Handbook by Robert Malmgren from Colorado State University.

This article was written with the help of Hilary Clayton, BVMS, PhD, MRCVS, Mary Anne McPhail Dressage Chair in Equine Sports Medicine at the Michigan State University College of Veterinary Medicine www.cvm.msu.edu/dressage and Annual Convention Proceedings of the American Association of Equine Practitioners (AAEP) 1990-1999, of which she is an active member.

AAEP contact information: 4075 Iron Works Parkway, Lexington, KY 40511 (859)233-0147 www.aaep.org

posted: 6/18/2002. Last updated: 3/8/2005.

 

Protecting Your Horse's Legs With Proper Bandaging Techniques

         

There may be any number of occasions when you will need to bandage your horse’s legs. Bandaging can provide both protection and support for the horse while working, traveling, resting or recovering from an injury. Regardless of the purpose, it is essential that you use proper leg bandaging techniques. Applied incorrectly, bandages may not only fail to do their job, but also may cause discomfort, restrict blood flow and potentially damage tendons and other tissue. It is often said that it is better to leave a horse’s legs unbandaged than to bandage them incorrectly. Fortunately, there is nothing complicated about learning to apply bandages. It simply takes the right materials and a bit of practice. If you have never bandaged a horse’s legs, ask your veterinarian to demonstrate the proper techniques. Practice under his or her supervision before doing it on your own.

Follow these basic guidelines from the American Association of Equine Practitioners (AAEP) when bandaging a horse’s leg:

1. Start with clean, dry legs and bandages. If there is a wound, make sure it has been cleaned, rinsed and dressed according to your veterinarian’s recommendations2. Use a thickness of an inch or more of soft, clean padding to protect the leg beneath the bandage. Apply padding so it lies flat and wrinkle-free against the skin.3. Start the wrap at the inside of the cannon bone above the fetlock joint. Do not begin or end over a joint, as movement will tend to loosen the bandage and cause it to unwrap.4. Wrap the leg from front to back, outside to inside (counterclockwise on left legs, clockwise on right legs).5. Wrap in a spiral pattern, working down the leg and up again, overlapping the preceding layer by 50 percent.6. Use smooth, uniform pressure on the support bandage to compress the padding. Make sure no lumps or ridges form beneath the bandage.7. Be careful not to wrap the legs too tightly, creating pressure points.8. Avoid applying bandages too loosely. If loose bandages slip, they will not provide proper support and may endanger the horse.9. Leg padding and bandages should extend below the coronet band of the hoof to protect the area (this is especially important when trailering).10. .Extend the bandages to within one-half inch of the padding at the top and bottom. If there is a potential problem with bedding or debris getting into the bandage, seal the openings with a loose wrap of flexible adhesive bandage.

For more information about bandaging techniques, ask your equine veterinarian for the “Leg Bandages” brochure, one in a series of eight bandaging brochures produced by the AAEP in partnership with 3M Animal Care Products.

2) Title/Bio: none 3) Source AAEP, 4) Date: March 29, 2001, 5) Menu category: lameness: general

posted: 6/18/2002. Last updated: 6/18/2002.

 

Lameness and Poor Performance in the Sport Horse: Eventing

by Sue Dyson, FRCVS

          Eventing (horse trials) combines dressage, show jumping, and cross-country, together with steeplechase and roads and tracks phases in a three-day event. The event horse must primarily be a brave, clever, bold jumper cross-country, with scope and speed. However, in modern day competition this is not sufficient to excel, and the horse must also have reasonably athletic paces and a temperament that can be trained for dressage, combined ideally with an ability to show jump with care. Horses with a predominance of Thoroughbred breeding excel. The majority of pure warmblood horses struggle to achieve the speeds required at top levels, and, if always working in top gear, are more prone to injury.Three-day eventing places extreme demands on the musculoskeletal system, through the efforts of both the training program and the competition itself. The horses compete on extremely variable terrain and must be able to cope with both hard and soft footing, often uphill, downhill, and across hills, and must be prepared accordingly. Galloping and jumping on various gradients place huge strains on the limbs and back, and horses with poor conformation are particularly at risk to injury.Eventing is less forgiving than dressage or show jumping in this respect. Dressage in horse trials is almost always performed on grass and subtle gait abnormalities may be highlighted, especially when the ground is hard. Horses with poor foot conformation, upright hoof pastern axes, are back-at-the-knee or have straight hocks do not stand up well to top-level competition. The event horse is also much more at risk to develop lameness due to direct trauma than horses in either show jumping or dressage, particularly in the cross-country phase.Horses usually reach advanced level by approximately 8 years of age and the majority of horses competing internationally are older. Most injuries in these horses are repetitive strain injuries to soft tissues or joints or the result of direct trauma, whereas in younger horses there is a broader range of lameness causes common to horses used in a variety of disciplines. Exertional rhabdomyolysis (tying up) occurs quite commonly and is most often recognized in the 10-minute break after the second roads and tracks phase, before the cross-country phase of a three-day event. The speed at which horses must perform, combined with jumping, results in a high incidence of strain of the superficial digital flexor tendons. This is probably also a cumulative injury reflecting frequency of competition and the speed at which the horse competes.

LOSS OF PERFORMANCE AND LAMENESS

Low-grade musculoskeletal problems may present as unlevelness in the dressage phase, especially when performing medium or extended trot, 10 meter diameter circles or lateral work. In show jumping the horse may show any of the problems seen in the elite show jumper. Cross-

country the horse may be reluctant to jump drop fences or to gallop down hill.It must also always be remembered that refusing may reflect lack of confidence of the horse or rider. A horse may compete very successfully at intermediate level but not have the confidence or scope to compete at advanced level. Horses that are too careful and try to avoid hitting fences may paradoxically not be brave enough for advanced level competition.

CLINICAL EXAM

A comprehensive clinical examination at rest is essential. The horse should always be assessed as a whole, not as a limb in isolation.Particular attention should be paid to:

-Foot conformation, trimming and shoeing, and shoe wear-Joint flexibility, resistance to limb flexion and rotation, and pain-Fluid swelling in the joints, especially in the fetlock and pastern -Neck and back flexibility and muscle tension -Size, shape and reaction to palpation of the superficial digital flexor tendons and the suspensory ligaments

The horse should be examined standing squarely on a hard surface to detect muscle wasting, which may reflect a chronic low-grade lameness. It should be assessed moving in hand, before and after flexion tests, on the lunge on both soft and hard surfaces, and ideally ridden, since frequently horses have several low-grade problems when presenting with reduced performance which will only become apparent if the horse is examined under a variety of circumstances. Nerve blocking is essential to unravel the entire picture.Significant inflammation of the superficial digital flexor tendon may be present without lameness and with minimal detectable clinical signs. Many riders apply a proprietary clay and bandage the limbs after fast work or competitions and this can suppress soft tissue swelling or mask localized heat. Whenever there is the slightest suspicion of injury the tendons should be examined ultrasonographically.

COMMON CAUSES

As described in the article, common causes of acute onset lameness in the event horse include:

- Inflammation of the suspensory ligament- Injury to the suspensory branch - Inflammation to the superficial digital flexor tendon - Exertional rhabdomyolysis (tying up) - Stifle trauma, including bruising, fracture of the patella or tibia - Foot soreness, trimming and shoeing problems - Over-reach - Traumatic arthritis of the fetlock and pastern joints - Degenerative joint disease of the hock - Inflammation of the digital flexor tendon sheath - Back and hip pain

It is vital to have the horse examined by a veterinarian at the earliest sign of a problem, whether lameness, resistance or the onset of heat or swelling, so that appropriate treatment may be instituted to prolong the performance life of the horse.

1. title Lameness and Poor Performance in the Sport Horse: Eventing2. author Sue Dyson3. bio FRCVS 4. source AAEP convention 5. date November 20006. category lameness: general performance medicine 7. text

posted: 6/18/2002. Last updated: 6/18/2002.

 

Applying Sweat Bandages To The Horse’s Leg

         

When your horse suffers a strain, sprain or traumatic injury, or is stall bound for extended periods, its legs may swell and become warm to the touch. Because inflammation and swelling can damage tissues and cause discomfort, your veterinarian may prescribe a “sweat” bandage as an aid in reducing fluid build-up in the legs. Although sweat bandages are effective, the science of how and why they work still isn’t precisely understood. The purpose of the sweat bandage is to generate heat (which may help dilate vessels and increase blood flow), add pressure and provide support. Whatever the mechanism, the combined effect seems to help the body dissipate excess fluid from the injury site and reduce inflammation. While sweat bandages are useful in reducing swelling, they are generally not recommended for recent injuries or those that include open wounds. Be sure to consult with your veterinarian before applying one.

The Sweat Bandage

What sets a sweat bandage apart from other wraps is that a “sweating” preparation or poultice is generally applied to the leg, covered with lightweight plastic wrap, and then bandaged. There are a variety of commercial and homemade preparations that can beused to sweat legs. The formulation your veterinarian recommends will depend onthe type of injury and his or her personal preference. Some of these may contain “osmotic” agents that actively help pull fluid from the cells.Common ingredients used in sweat preparations include:- DMSO (dimethylsulfoxide)- Nitrofurazone Ointment- Mineral Oil- Petroleum Jelly- Epsom Salts- Glycerin or Glycerol

Proper Bandaging Techniques

It is essential to use proper techniques when applying a sweat bandage.Applied incorrectly, the bandage will not only fail to do its job, it can cause discomfort, restrict blood flow and potentially damage tendons and other tissue.(It is often said that it is better to leave a horse’s legs unbandaged than to wrap them incorrectly.)

Remember, padding is essential for protecting limbs. At least an inch or more of soft, cushioning material should be placed between the limb and the support bandage to distribute the pressure

evenly and prevent blood flow frombeing restricted.

MaterialsMaterials needed for the sweat bandage include:

- Sweating compound (preparation)- Lightweight plastic wrap (kitchen varieties work well)- Sheet cotton, roll cotton, combine cotton, or leg quilts for padding- Flannels, stretch gauze, stable wraps or stretch bandaging tape such as 3M Vetrap Bandaging Tape at least 2-3 inches wide for support- Stretch adhesive tape such as Elastikon Elastic Adhesive Tape to protect, seal and secure the bandage

Note: Commercial poultices are available.

General Guidelines

If you have never bandaged a horse’s legs before, ask your veterinarian or an experienced equine professional to demonstrate the proper techniques. Practice under his or her supervision before doing it on your own.

Follow these basic guidelines:

1. Start with clean, dry legs and bandages.2. Applying sweating preparation liberally to the entire segment of the leg to be bandaged.3. Surround the leg completely with plastic wrap, keeping the layers as smooth as possible.4. Apply padding over the plastic wrap, encircling the leg with an inch or more of cotton or quilting. Make sure that it lies flat and wrinkle-free against the skin.5. Wrap the leg with support bandaging fabric at least 2-3’ wide, working from front to back, outside to inside (counterclockwise in left legs, clockwise in right legs).6. Wrap in a spiral pattern, beginning at midpoint and working down the leg and up again.7. Overlap each preceding layer by 50 percent, exerting just enough pull to stretch the fabric to half its maximum extended length.8. Use smooth, uniform tension to compress the padding without forming lumps or ridges beneath the bandage.9. Use enough pressure to minimize swelling and keep the bandage in place, but never wrap so tightly that you cannot easily slip finger between the bandage andleg.10. Avoid applying bandages too loosely. Loose bandages are ineffective and may endanger the horse.11. Extend the support fabric to within a half-inch of the padding at the top and bottom.12. Check bandage periodically to make sure it is secure yet not interrupting circulation.13. If there is a potential problem with bedding or debris getting into the bandage, seal the top and bottom of the bandage with a flexible adhesive bandaging tape such as Elastikon tape.

Special Considerations

- Do not leave the sweat bandage on for more than 12 hours. After 12 hours, remove the wrap, allow the leg to “rest” for 12 hours, and reapply the sweat bandage if necessary.- After unwrapping, take a few minutes to examine the leg. It should benoticeably improved. If there are signs of increased heat, swelling, drainage or skin irritation due to the sweat, consult your veterinarian.- A horse with a condition requiring a sweat bandage should be confined to a stall or small run

unless otherwise directed by your veterinarian.- If DMSO is an ingredient in the sweating compound, make sure the horse’s skin is dry before applying it to reduce the chance of skin irritation.Wear gloves to protect your hands.- Check the bandage several times a day to make sure it has not tightened, loosened or slipped out of place.- Make sure the bandage does not cut off circulation, compress tendons, create pressure sores or cause skin irritation, redness or discomfort.- Monitor and evaluate the horse carefully. If swelling develops above or below the bandage, lameness increases, or the horse becomes distressed or begins to bite, paw or rub the bandaged site, check the leg and contact your veterinarian.- Watch for any other signs of ill health. If the horse becomes depressed, irritable, loses its appetite or has an elevated temperature, consult your veterinarian.- If you have any further questions or concerns about sweat bandaging, contact your veterinarian.

This information was produced through a joint venture between 3M Animal Care Products and the American Association of Equine Practitioners.

posted: 6/18/2002. Last updated: 5/6/2003.