Splints are bony lumps usually seen on the inside of the upper half of the cannon and splint bone in the forelimbs. They most commonly occur in younger horses and can be caused by trauma or by injury to the ligament between the cannon and splint bones (the interosseous ligament). The trauma causes inflammation to occur, and this results in new bone development between the splint and cannon bones to stabilise the site of the injury. This ultimately results in a palpable bony lump. As the lump is growing, and is caused by inflammation, it is often slightly warm and painful to the touch. Lameness may or may not occur. If lameness is present it is made worse by hard work.
Splints are often diagnosed clinically (on examination) by vets, but their presence can be confirmed using X-Rays. If the lameness is pronounced, however, even if the signs of the splint are convincing, X-Rays must be performed to rule out fracture.
The primary treatment for horses with splints is rest, cold therapy, anti-inflammatory drugs, and bandaging of the affected area. The prognosis for return to work is good to excellent, although some bony growth usually remains in that area long-term. Very occasionally the bony lump may be in a position where it affects the suspensory ligament, and in these cases surgery may be required.