Evaluating the Lame Horse

Stress, strain or injury can take a toll on any horse's health, even one with no obvious conformation defects. When lameness occurs, contact your veterinarian immediately. An 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 prepurchase examinations. When your veterinarian evaluates an animal you are considering for purchase, you could 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 manifested 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 methods for performing lameness 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 the past and present difficulties of the horse. He or she also will inquire 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, and look for any evidence of injury or stress.
• A thorough hands-on exam during which 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 60-65 percent of the horse’s weight is supported by the front limbs.
• Evaluation of the horse in motion. The veterinarian watches the horse walking and trotting. Gait evaluation on different ground surfaces (soft to hard) can give valuable information as to the nature of a particular lameness. 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 vet will also watch as the horse walks and trots in circles, on a longe line, in a round pen and under saddle. The veterinarian looks for certain signals, 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 might reveal problems that are not otherwise readily apparent.

Diagnostic Tests

Diagnostic procedures can 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, like those listed below.

• 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. Blocks can also help determine whether the condition is treatable.
• Radiographs. These 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 troubled 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 are examined for infection, inflammation or metabolic abnormalities (muscle biopsy). These exams usually require lab testing.
• Magnetic Resonance Imaging. A recent tool employed to evaluate soft-tissue and bony problems primarily of the lower leg, an MRI provides excellent resolution and detail. Limited availability may be a short-term problem.

Preventing Lameness

Adequan® i.m. (polysulfated glycosaminoglycan) is like no other equine joint treatment available. After 30 years, it’s still the only PSGAG FDA-approved joint product. For full prescribing information, go to Adequan.com. Adequan® is the official equine joint therapy of AQHA. Learn more at www.aqha.com/adequan.