Lameness

Though lameness is a term that covers a broad spectrum of ailments, it can be defined simply as an abnormality in a horse’s movement caused by pain or reduced range of motion. It is commonly used interchangeably with the term unsoundness since a “sound” horse is one that is not lame. Though often thought of as a problem of the feet or legs, lameness can involve virtually any part of the body and can originate in bone or soft tissue.

Veterinarians often use a grading scale to describe various degrees of lameness. Most use a scale from 0 to 5, with 0 being sound and 5 being non-weight bearing on a limb.

Additional terms used to categorize lameness are acute and chronic. Acute refers to lameness that came on recently and often suddenly while chronic refers to an ongoing lameness that the horse has had for a longer period of time. Both acute and chronic lameness can fall anywhere on the severity scale; but, in general, chronic lameness tends to be relatively mild.

Other important variables of lameness are whether it is persistent or intermittent, and progressive or static. Many people confuse the terms persistent with chronic, but the latter refers to the length of time of the problem while the former means that the lameness (which could be recent or not) has been consistently observable since its onset – not coming and going.

Signs of Lameness

Moderate to severe lameness is usually easy to recognize since a horse will often display a marked abnormality in its gait, a distinctly odd stance, or an inability to bear weight on the affected limb. In extreme cases, the animal may be recumbent and unable to stand at all. When lameness is more subtle, however, it can be difficult to spot. A horse with a subtle lameness may demonstrate any number of behaviors that are easy to misconstrue as a training problem or some other kind of problem. In order to avoid pushing a horse that may have a legitimate physical problem, it is necessary to recognise not only the obvious signs of lameness but also the more subtle ones.

Front end pain: Unilateral front end lameness is generally easy to spot since it usually involves some degree of “head-bobbing” or nodding. Other symptoms include toe pointing: the horse stands with the sore forelimb in front of the normal placement with the heel lifted partially or totally off the ground. Bilateral front end lameness may cause symptoms such as short, choppy strides, frequent weight shifting when standing, or a “sawhorse stance,” in which the front legs are “camped” or stretched forward. The hind legs are also more forward than usual as the horse tries to take more of its weight on its hind end.

Hind end pain: A horse with lameness in the hind end will often take distinctly shorter steps with one hind leg (most easily observed from the side), and will frequently drop one hip much lower than the other (easiest to see from behind the horse as it is moving away). Depending on where the problem is, the horse may show secondary symptoms such as poor hind limb propulsion, back pain, difficulty picking up a lead or making transitions, bucking, cantering disunited (cross-cantering), resistance to a bend or turn, or uncharacteristic misbehavior when being tacked up.

Foot pain: The most common symptoms of foot pain include toe pointing, the “sawhorse stance,” frequent shifting of weight when standing, reluctance to turn tightly, and toe-first landing during movement.

Multiple sites: Whether the signs are distinct or subtle, pain can commonly occur in more than one location, often affecting two or more limbs. This can be a result of a systemic problem (such as laminitis) or a result of the body attempting to compensate for the initial lameness, thus putting strain on other parts of the body. Localisation and identification of the cause of lameness in such cases can be particularly tricky.