Equine Orthopaedics and Rheumatology Q&A 15

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A horse presented with a grade 2/5 lameness, at the trot, in a straight line, on the left forelimb. The lameness was increased when the horse was trotted in a circle with the lame leg on the outside. Flexion tests failed to exacerbate the lameness, but hoof testers produced a positive result on the hoof’s medial aspect. The image illustrates the sole of the left fore foot after paring.

Question	Answer		Article
What condition is illustrated?	A ‘corn’ – bruising of the sole in the angle between the medial hoof wall and the bar (the ‘seat of corn’).		Link to Article
Why is the lameness worse in the affected limb outside the circle?	The bruising is usually present on the medial side of the fore feet. Lameness will be more severe when loading of this area is greatest and, in the case of the medial side, this will be when the affected limb is on the outside of the circle.		Link to Article
What causes this condition?	‘Corns’ are usually caused by badly fitting shoes. This can occur if shoes are too small, when the branches will lie over the ‘seat of corn’ and will result in bruising of this region. Alternatively, correctly fitting shoes which are left in place for long periods will move to cover this sensitive area as the foot grows.		Link to Article
How would you treat this horse?	The badly fitting shoe should be removed, and the affected area pared out. Paring should be halted once the bruised area is identified. If the ‘corn’ has become infected, paring should be continued to establish drainage (as for a solar abscess). The foot can be left for a few days for the bruising to heal and the horse to become sound. When shoes are re-applied, care must be taken to avoid pressure in this region – shoes can have the caudal end of the medial branch seated out, and in some cases the heel widened so that it covers and protects the affected area while still being supported by the wall.		Link to Article