by William Moyer, DVM
Professor of Sports Medicine
How to recognize foot problems
Keep in mind that the following are generalizations. The signs that one sees are based on the interpretation of pain relative to the individual horse. How it interprets the painful response and the intensity will, obviously, determine the way in which the animal uses a given limb. The following are generalities:
- Consistent pointing of a given foot (either exaggerated or consistently evident).
- Hoof warmth (meaning that one foot is consistently warmer than the other).
- Increased digital pulse pressure.td>
- Changes in hoof shape usually suggest a chronic problem — usually the affected foot is smaller than the “normal” foot.
- Discomfort when the farrier is either pulling the shoe or re-nailing a shoe.
- The degree of change in motion is more exaggerated in small turns and on hard surfaces.
Subtle Signs May be a Function of the Given Sport
Again, we are talking about generalities. Often particular types of foot problems occur more frequently in a given sport or breed type.
Often the history indicates that there is a tendency to bear in or out going into the turns. The history may also indicate that there is a drop in performance without an obvious illness or lameness.
The history (that which the owner is seeing or feeling) may consist of a refusal or loss of rhythm going into a fence and often a scrambling of the hind legs in an effort to get the weight off of the front end. The history may indicate that the horse is now showing an inability to take sharp turns on a jumping course.
Invariably the history here is that of a choppy gait and/or unwilling to go down any kind of a grade.
Cutting Horses, Barrel Racing, Polo Ponies
Often the history here is a loss of precision when turning. In other words, the horse is no longer able to take that real sharp turn, and tends to be worse on one side or the other.
Usually the rider feels a loss of what was thought of as a fluid motion. This is particularly evident when horses afflicted with foot problems are asked to do side passes. Invariably, the rider “feels it” as a shoulder problem.
Obvious Visual Signs
Often there are aspects of the foot that are quite visual and, therefore, become obvious. This may consist of hoof cracks, hoof wall loss and/or breakage, excessive hoof wall flaring (a change in shape over a period of one or two resettings of the shoe), a low or literally non-existent heel length with a long toe, excessively high heel and toe angle (with or without a “dish” appearance— usually termed a club foot).
The Most Common Problems
Generally, most foot problems will initially appear to be the same to the owner, that is, an individual horse that is “off” or, frankly, lame. Most foot problems will show pain with hoof testers, usually are more obvious when being ridden or jogged on hard ground, more obvious on the turns, etc. Usually, such problems require a thorough examination to arrive at an accurate diagnosis.
This is the most common foot problem, by a wide margin. It simply represents either repetitive or a single focal forceful crushing of the sensitive tissues which exist between the sole and the third phalanx. Subsolar hemorrhage occurs as a result of this trauma, placing constant pressure on nerve ends and, thus, pain/lameness. Keep in mind that it can come on either slowly or rather suddenly. The most common site on the foot (sole) is the heel region (also called the “corn” region).
Horses that tend to have flat, weak heels are obviously the most susceptible horses for this problem. Usually focal pain exists in the area of the bruise when applying hoof testers. A properly applied nerve block will return soundness. The most critical aspect of treating such a problem involves correcting the cause, if possible. This requires a careful, exact shoeing and often patience on the part of the owner/trainer. Most people tend to think that a bruise is a reasonably easy problem to treat—that can be very misleading. In the event that the horse has badly-made feet, it can be as difficult to manage as navicular disease or other chronic problems.
Puncture Wounds and Gravel
Foot infections are common for obvious reasons. Usually the onset of pain and lameness is sudden and at times quite severe. A “gravel” is simply an infection which exists at the junction of the sole and the wall (termed the white line). A gravel may be the result of a poorly placed nail or the result of embedded foreign material in the white line.
The severity of any foot infection is determined by its location and depth. The most serious involve the tissues in and around the navicular bone, coffin joint, or third phalanx. Septic (infectious) involvement of these areas can be, at times, life threatening. Most local infections require nothing more than localization, drainage, and protection of the area while it is healing. The more seriously involved infections usually involve surgical drainage and significant medication and support.
Hoof Cracks and Hoof Wall Loss
Such problems can occur with any horse under any set of circumstances; but, the most common situation that we encounter involves racehorses. Cracks and/or loss of hoof wall can occur anywhere in the foot (the most common area being at the quarters and heels). The severity of the problem is determined by the location (the worst being the heel region), the depth of damage (whether it is superficial or into sensitive tissue), whether or not infection exists, the degree of instability that is created, and the length of the defect. Management requires careful trimming/shoeing, stabilization of the defect, and usually time off to allow new growth of hoof wall.
Management may be as simple as time (let it grow out), or as sophisticated as special shoe design and implants (hoof wall patches). The ideal hoof wall patch material provides significant stability without rigidity.
Laminitis is one of the great medical mysteries in the horse world. Active research is ongoing to determine the mechanism that creates this disaster. The basic problem is that of a relative or complete shutdown of blood flow (and, thus, loss of oxygen) to the laminar tissues. Cellular death follows loss of oxygen and, thus, the support system that exists between the third phalanx and the hoof wall is compromised, or in some severe cases, totally lost. Ultimately, depending upon the degree and duration of the insult, the third phalanx changes its position within the hoof capsule (termed rotation or downward displacement, as in a sinker).
Any number of initiating causes have been identified (diarrheas, various respiratory diseases, wound infections, foaling problems, grain overload, etc.). Basically, any disease situation has the potential to initiate the cascade of events leading to laminitis.
It is, at best, a difficult disease to treat and manage—the reason being that significant damage has already occurred before the signs of lameness appear—thus, the first time the owner is aware of a problem. Usually, it presents as a bilateral foreleg stiffness, unwillingness to move, or obvious lameness and an exaggerated stance. The best advice is to have any suspected horse examined on an emergency basis. Do not delay hoping that the problem will go away.
In the event that you end up dealing with what is termed a chronic situation, get as much information (thorough examination, radiographs, etc.) as you can to appreciate the future realistically. Keep in mind that invariably the involved foot or feet will always be susceptible to recurring foot problems.
Navicular disease is best described as a chronic, degenerative process involving the navicular bone, the deep flexor tendon, and associated soft tissues (navicular bursa, ligaments, etc.). It can be, in the absence of obvious radiographic changes, a difficult diagnosis to confirm and, thus, it is a controversial disease.
The incidence of navicular disease appears to be highest in Quarter Horses (stock horse types), Warm Bloods, and horses that jump. It is seldom diagnosed in young horses (other than Quarter Horses and stock horse types) and is rare in Arabians and Standardbreds.
Usually the owner/trainer/rider “feels” a mild change in gait well before obvious lameness is apparent. Like so many lamenesses, it is apparent (more obvious) on hard footing and in the turns. Commonly it involves both front feet, but it is usually more obvious in one than the other.
Management usually involves various attempts at changing foot angles, pads, and anti-inflammatory medication such as Butazolidin. Isoxsuprine (not licensed in Canada) is often added to the medication regimen. The horse owner must, however, understand that if an individual horse truly has navicular disease it will not go away. It may or may not be satisfactorily managed and that one cannot predict with any accuracy what the outcome will be. Neurectomy surgery (cutting the heel nerves) is an option, but, again, the owner must be informed of the risks involved.
Foot problems are the most common lameness dilemmas encountered. Most will initially appear to be similar. The foot is a small and highly complex piece of equipment. An accurate diagnosis requires a thorough examination and understanding of foot anatomy and provides the only avenue to proper management of the problem.