Hyperextension of the carpus causes the lower foreleg to bend abnormally, bringing the dog's palms closer to the ground. It is a common transient deformity in young, growing puppies. The growth rate of the bones, ligaments, tendons, and joints may not be in perfect harmoney in fast growing animals, causing the crooked joints. Large breed dogs who are fed high calorie, high protein growth diets experience these problems most often. In addition to breed and diet, genetic predisposition also plays a major role.
Most mild cases are self limiting, and resolve when the other parts of the growing leg catch up.
In more severe cases, meta splints applied to the legs for a few weeks provide the needed support while the carpi straigthen. The opposing factors of the body's tendency to grow out of such a problem, and the rising dog's weight increasing the angulation can take weeks to months to either resolve the problem, or to destroy the joints. Early attention is important to produce a favorable outcome.