A sickle-hocked leg structure is one in which the back leg joints of an animal, usually a horse or other equine mammal, are set with too much angle, resulting in the hock also being excessively angled. This can result in uneven hoof wear, which is incredibly painful for the affected horse. If the leg joints are not set properly, there is a high chance that the back joints are also set incorrectly, resulting in a poorly conformed horse.