“The lower limb is the most common site of lameness in 'English' sport horses,” noted Rick Mitchell, DVM, MRCVS, of Fairfield Equine, in Newtown, Conn. Thus, sport horse practitioners must be well-versed in how to diagnose injuries in this region, he said, and should take a "more aggressive" approach to diagnosing these horses to try to reduce as much loss of training and competition time as possible.

Mitchell, who treats high-performance sport horses in his practice, described his diagnostic approach at the 2013 American Association of Equine Practitioners Convention, held Dec. 7-11 in Nashville, Tenn.

Mitchell started out by characterizing the unique anatomical qualities of the equine hoof that enable it to work as a shock absorber—ranging from the corium parietis and the digital cushion to the natural coffin bone movement within the hoof wall and foot balance—but also predispose it to potential injury. Additionally, he listed important factors that can influence lameness development:

• Conformational predisposition;

• Repetitive loading;

• A long toe, low heel, and/or broken-back hoof-pastern axis;

• The manner and frequency with which the horse is shod–medial to lateral (side-to-side) balance and breakover (the moment the heels lift off the ground, which can be impacted by how the farrier adjusts the toe) might be major contributing factors; and

• The footing on which a horse works.

Mitchell noted that the timing of a lameness exam is critical because a horse can improve with a few days of rest after the owner notes a lameness or performance decline. "Such mild lameness issues may be best re-examined after a day or two of exercise," Mitchell added