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Common Lameness Conditions

Common Lameness Conditions

Puncture Wounds

Puncture wounds of the foot are common and can result in an abscess developing below the sole. The wounds often go undetected until the horse presents with a sudden onset of moderate to severe lameness due to the pain associated with it. Applying a poultice to draw out the infection and encourage it to drain is critical to get resolution. Your veterinarian will be able show you how to apply a poultice. Commercially available products are available and are easy to apply. A number of homemade recipes can also be found, frequently making use of compounds such as Epsom salts or sugar. Close examination of the sole of the foot may help to pinpoint the site of the abscess. Paring of the sole by your farrier at this site should result in drainage – again, consult your veterinarian. Administration of an antibiotic is usually not necessary. Healing is frequently without any long term consequences.

Thrush

Thrush is a condition of the frog of the horse's foot, and is often predisposed to by prolonged periods of standing in unhygienic conditions (manure, urine). The frog degenerates and bacteria proliferate in the tissue resulting in further maceration and a black, malodorous discharge. The condition can occur without lameness; this depends largely on the severity of the condition. Improving cleanliness of the horse's environment and topical treatments, with removal of diseased tissue, as/when recommended by your veterinarian will usually resolve the problem.

Tendon and ligament injuries

The horse's legs have several important ligaments and tendons located on both the front ("anterior") and back ("posterior") aspects of the forelimbs and hindlimbs. These are critical structures for support during normal weight bearing and for movement and have little or no extra tissue overlying them that might protect them. Injuries are not uncommon and, depending on the severity and type of injury and the particular tendon or ligament affected, can have very serious consequences with respect to prognosis and ability to return to work. "Desmitis" refers to inflammation of a ligament whereas "tendinitis" refers to a tendon. Tendinitis is sometimes referred to as bowed tendon. Ruptures and lacerations of these tissues can also occur.

Osteoarthritis

Osteoarthritis is also known as degenerative joint disease. It is a progressive deterioration of a joint and represents the end stage of any condition(s) that may have affected that joint, particularly if the condition was unsuccessfully treated, or periodically recurred, or was severe. Osteoarthritis is also the result of, or compounded by the normal age-related wear and tear that occurs within a joint. Although no horse is immune to the wear and tear process, the type of work that he has done in his lifetime – both the intensity and frequency - are likely to have a significant impact on the development of these changes. The high performance dressage horse, for example, is likely to have more severe degenerative changes in some joints than a "pasture ornament" horse. Lameness is a result of pain both in and around the joint and the structural changes due to the degeneration within the joint. Treatment of osteoarthritis is palliative; however, early detection is important so that consideration can be given to modifying the horse's work load/work level. It will be important to maintain some level of exercise. Your veterinarian may also prescribe a nonsteroidal anti-inflammatory drug and recommend other modes of therapy such as massage or chiropractic, which may be helpful. Injections of drugs that have anti-inflammatory and analgesic effects directly into the affected joints (intra-articular) are also used in some cases.

Bruised Sole

Sole bruising is an injury that results in hemorrhage involving the sole of the foot, most frequently the front feet. It is usually due to direct injury from stepping on stones or other materials or irregular ground. Some horses and some breeds seem to be predisposed to this condition because they have thin soles and/or flat feet (e.g. Thoroughbreds). However even horses with so-called "normal" soles can develop bruising if ridden over rough and rocky ground.   

Bruising can result in a severe, sudden lameness or it may be milder and intermittent. This largely depends on the location of the bruising and the amount of damage that has occurred. In milder cases, the lameness may present as a stiff or stilted gait more noticeable at the trot. If the lameness is severe, you will probably contact your veterinarian to rule out other causes for the lameness.

Depending on the degree of pain and lameness, your veterinarian may prescribe an anti-inflammatory drug along with soaking the foot in Epsom salts to reduce inflammation. In some cases, therapeutic shoeing might be indicated.  Rest will help to prevent further trauma as healing progresses. For horses that continually bruise their soles, the use of shoes +/- pads may be recommended.  

Laminitis

Laminitis is a very serious condition affecting one or more feet and management and treatment will involve your veterinarian. Making the call to him/her in the early stages of laminitis will help give your horse the best chance at recovery.    

Most often it is the front feet that are affected and the horse takes up a "sawhorse" stance with the front feet placed forward and the hind feet well under the body. Lameness is often severe and the horse is reluctant to move. If all four feet are affected, the horse tends to place all feet well under its body when standing. There are some horses that will present with a milder form with less pain in the feet and a milder lameness.  

Your veterinarian will probably want to radiograph (x-ray) the affected feet. In this way, the position of the coffin bone can be visualized. Further radiographs can be taken as treatment proceeds to help assess and monitor the condition.

Laminitis affects the sensitive tissues that attach the inner lining of the hoof wall to the surface of the coffin bone. The lamellae (laminae) or leaf-like structures within this tissue that form the bonds resulting in attachment stretch and detach and weaken the tissue. When this occurs, the coffin bone is free to rotate downwards due to tension from the large tendon that is attached to it (DDFT/deep digital flexor tendon). Over time the bone may actually rotate so much that the tip of it penetrates through the sole.  

Much research is being done to understand why this disease occurs. Current thinking is that attachment between hoof wall and the coffin bone is destroyed due to the uncontrolled activity of certain enzymes. These enzymes are normally present in the hoof and play an important role in maintaining the health of the lamellae. However, under some circumstances, their activity goes out of control and results in destruction of the tissue and laminitis.   

What triggers their uncontrolled state is an area of active research. An understanding of these triggers will be important in developing effective treatments and effective ways to prevent the disease. It is thought to involve a combination of hormones and inflammatory proteins that are released under certain circumstances including certain metabolic states and diseases.    

For some conditions that have been associated with a risk of laminitis, endotoxin may be involved as a trigger:

  • Colitis (inflammation of the colon)
  • Metritis (inflammation of the uterus)
  • Retained placenta (failure to pass the afterbirth) after birth of a foal
  • Grain overload
  • Cushing's disease

Obesity in horses suffering from Equine Metabolic Syndrome has been recognized to be a risk factor for developing laminitis. Excess body weight also seems to be a risk factor for pasture-associated laminitis – particularly when pastures are growing or lush.     

Treatment and Management: Early recognition and treatment of horses suffering with laminitis is very important to try and prevent complete rotation of the coffin bone and to minimize long term damage. Treatment will also need to be directed at any other condition that is present such as metritis or retained placenta or grain overload. Treatment of the foot will focus on relieving pain and relieving stress on the DDFT to help prevent or minimize rotation of the coffin bone.

  • Analgesics will be paramount. A nonsteroidal anti-inflammatory drug will be prescribed by your veterinarian to reduce both the pain and the inflammation.
  • Strict confinement to a stall with thick, deep bedding (sand, peat or shavings) to help provide support to the foot.
  • Stall rest to reduce movement or, if stall rest is not possible, confinement to a 
    small paddock. Exercise during the early phases of the disease can potentially worsen the outcome.
  • Cooling the affected foot in the early stages – so-called "cryotherapy" with a slurry of crushed ice or circulating cold water. "Ice boots" have been used early on in some cases.
  • Therapeutic trimming of the foot and application of mechanical support for the coffin bone. This may take the form of a commercially available wedge applied to the ground surface of the foot or pads made from high-density foam. Work with your veterinarian and farrier for the best approach with your horse.

Long term management often involves therapeutic trimming and shoeing with frog support as the hoof wall will tend to grow unevenly. Weight reduction in the case of the overweight patient will be important.

Navicular Disease or Navicular Syndrome

Navicular Disease is another complex condition in the horse. It is described as a chronic forelimb lameness associated with pain that comes from the navicular bone and any of its closely related structures. It is manifested as "heel pain." Affected horses can present with sudden onset of relatively severe lameness in one or both front feet. However, the lameness may be much more gradual in onset. Some breeds seem to be predisposed and this is probably related to the natural conformation (shape) of their feet. Lameness usually is seen in horses that are 7 to 9 years of age although this can vary. Affected horses may show shortened strides or lameness that shifts from one foot to the other accentuated by hard ground.   

Your veterinarian will examine the feet closely and may advise that certain diagnostic tests be conducted. Radiographs, nerve blocks with a local anaesthetic, and other tests can help to pinpoint the origin of the lameness.

Treatment and Management
Unfortunately there is no "cure" for navicular disease at this time. Instead, this is a disease that requires managing. Successful management is likely to involve a combination of drug therapy and therapeutic trimming and shoeing, with the goal being to return the patient to work. With this in mind, it will be helpful to the horse to have both a veterinarian and farrier involved in its care. Medically, your veterinarian will prescribe drug(s) based on the stage of the disease. Nonsteroidal anti-inflammatory drugs are used to help alleviate pain. There are a number of other drugs that might also be prescribed to benefit blood flow to the foot (e.g. isoxsuprine, pentoxifylline. In some individuals, the veterinarian might suggest an intraarticular treatment with an anti-inflammatory drug.

Therapeutic trimming and shoeing will be important parts of the management of the disease. The foot should be trimmed to maintain heel mass, and shorten the toe to facilitate breakover. A variety of shoes are available that have been used successfully in navicular cases. Shoes that provide a greater ground contact surface often help as does elevating the heel with a wedge pad or specific type shoe.   

The ultimate goal of both trimming and shoeing is to maintain the foot, especially the heel area, and protect the heel region of the foot from concussion.

There are also several surgical procedures that may be done involving the nerves or ligaments in the region. These may be suggested on a case-by-case basis but are usually reserved for horses that responded poorly to other treatments and/or continued degeneration of the navicular bone.