Angular limb deformities (ALD) are a type of Developmental orthopedic disease (DOD) found in young, growing horses. ALD can be either acquired or congenital deformities in a young foal. ALD is presented as either a valgus deformity or a varus deformity. Valgus deformities give the horse a 'knock-kneed' appearance and are the lateral deviation of the leg situated away from the center of the body to the location of the deformity. Varus deformities are the medial deviation of the leg situated away from the center of the body to the location of the deformity, giving the foal a 'bowlegged' appearance. Both types of deformities are also typically associated with a certain degree of axial rotation.

Deviations which occur in the fetlock are considered more urgent. Management of ALD in foals must begin early. Once the foal's growth plate closes, any potential for therapeutic intervention to correct the limb deformities is lost.