The splint bones, also known as the metacarpal (forelimb) or metatarsal (hindlimb) bones, are the small bones found on each side of the cannon bone, and they extend from the knee (carpus) to just above the fetlock. The strong ligament between these bones and the cannon bone is called the interosseous ligament, and this ligament hardens to bone as the horse ages. 

Signs to Look out For

A large firm lump on the inside of the horse’s front cannon bone will mean that he has a “splint”.  This lump starts as a fibrous, inflammatory reaction to injury and can progress to a bony growth of the splint bone. It is common in horses.

This swelling is likely to have developed quickly and feel warm to the touch.  Your horse may be lame depending on how much swelling there is, but also, they may show no signs of lameness or pain. 

Causes

Splints can be caused by damage to the interosseous ligament. This in turn is usually caused by too much work on a hard surface. However, it can also be caused by an injury such as a kick to that area. 

Treatment

If you suspect that your horse has thrown a splint it is best to get the vet to come out and diagnose the problem and then discuss with them the best way forward. Early detection will help to reduce the recovery period and will avoid it becoming a more serious problem. 

There is not usually a quick fix for splints so a period of rest will be required for your horse.  This is likely to be a minimum of four weeks but could take up to 12 weeks.  Management in the form of cold-hosing, counter pressure bandaging and box rest may also be required, but your vet will advise you on this.

It will be very important to bring your horse back into work slowly after a splint injury to avoid the problem reoccurring.

Prevention

As most splints happen in young horses it is best to take your time when bringing a young horse into work. Don’t rush the young horse so that it has time to develop slowly, and hopefully without complications.

Don’t ride on hard ground for too long if possible and avoid deep or uneven surfaces.

If your horse has conformation problems with their front legs, then be mindful of this and don’t ask too much of them.

Keep your horse active and a good healthy weight as obesity in older horses has been linked to the formation of splints. Although splints are most common in younger horses, if an older horse gets one then unfortunately, they tend to cause more lameness problems. 

If your horse has had a splint in the past then try to protect that area when he is in work by using well-padded and well-fitted boots or bandages.

Splints generally settle and don’t cause further problems for horses. Your horse may be left with a cosmetic blemish, but this is all.