Splints primarily involve the interosseous ligament and periosteum between the large metacarpal (third) and small metacarpal (less frequently, metatarsal) bones. The pathological process is a periostitis with production of new bone (exostoses) along the involved splint bone.
Contributory factors include trauma from concussion or injury, strain from excess training (especially in immature horses), faulty conformation, unbalanced nutrition or overnutrition, or improper shoeing.
When splints arise spontaneously, as they usually do, they almost always occur medially. Lateral splints are more often the result of blunt trauma or fracture.
Lameness due to splints occurs only when they are forming and is observed most frequently in young horses. Splint-induced lameness is more pronounced after the horse has been worked.
In the early stages of splint development, there is no visible enlargement of tissue on the legs; however, deep palpation might reveal local, painful, subperiosteal swelling. In later stages, an exostosis appears.
After ossification of the splint, lameness disappears, except in rare cases in which the growth encroaches on the suspensory ligament or carpometacarpal articulation. Radiographic examination is necessary to differentiate splints from fractured splint bones.
Complete rest and anti-inflammatory therapy are indicated for splints. Intralesional corticosteroids can decrease inflammation and prevent excessive bone growth. Their use should be accompanied by supportive bandaging.
If exostoses impinge on the suspensory ligament, surgical removal might be necessary.
For More Information
Also see pet owner content regarding splints.
