“Splint” is the term used to describe a bony hard lump that can appear where the splint bone and the cannon bone touch. When they first appear, the horse is often slightly lame – this lameness can last up to 6 weeks. The swelling is painful when pressure is applied – this pain also can last up to 6 weeks. Some splints are quite large – these should be checked by your vet as there may be a fracture of the splint bone present. Because the splint bone takes weight at the knee, and ends above the fetlock so cannot pass this weight on through the fetlock to the ground, it must transfer the weight taken at the knee to the cannon bone – and it does this via a ligamentous attachment to the cannon bone throughout its length. If there is a tear in this attachment, or a bruising of the splint bone, a splint appears. This splint is the horses bodys attempt to stabilise the injury so the weight transfer process can continue. It follows from this that, if a splint should appear on your horse, you should rest the horse for at least 6 weeks to allow healing to occur – if you continue to exercise you horse, the splint will get bigger as the tear gets bigger.
Some horses are more prone to splints because their cannon bones (especially the front legs) are offset – ie looking at the legs from in front of the horse, the leg below the knee is not in a straight line from the shoulder to the hoof – it is displaced sideways. So the splint bones on that leg do not take equal weight – the one taking more weight is more prone to “popping a splint”. If you have a young horse with this anatomical make-up, waiting until it is mature (5 to 6 years old) before putting too much pressure on helps prevent these splints occurring.
Preventing splints in all horses relies on correct hoof dressing and shoeing, having the horse fit and healthy, and avoiding accidents.
Treatment of splints varies according to their size, location, and cause. If a splint occurs in the upper third of the splint bone, surgery is seldom indicated, as too much weight transfer occurs above this and removal can result in permanent lameness. Talk to your vet on your options. Surgical removal of the splint or splint bone below the splint is a good option if the splint is in the lower half of the splint bone length. However, if no fracture is present, and the splint is not recurring, and is small, by far most splints are left alone to heal and cause no further problems once healed.