Equine splint bones run down each side of the horse's leg and attach by ligaments to the shinbone, also called the cannon bone. A remnant of the five toes possessed by prehistoric horses, the splint bones can be compared with the first and third finger--the ring finger--of humans, says veterinarian Frank Santos on the MyHorse website. Splint fractures differ in their location on the bone, the complications that can ensue and their causes, but all involve a significant break on one or both of these bones. Veterinary treatment varies depending on these factors.
Causes
Complicated fractures of the upper splint bones usually result from direct trauma--commonly a direct hit to the skin surface when the horse kicks a solid object or receives a kick from another horse. In their book "Practical Guide to Lameness in Horses," Ted Stashak and Cherry Hill report that many of these fractures result in open skin wounds and may lead to bone infection.
When there is no skin break, veterinarians may surmise that the fracture occurs when the attached cannon bone torques at high speed and the fragile splint bones break at the tips. Horses that race and cut cattle may be predisposed to this type of injury.
Symptoms and Diagnosis
Fractured splint bones often involve inflammation, swelling and pain upon palpation. The horse typically shows severe lameness and may be bleeding or have a draining tract in the area of the initial injury, writes veterinarian Hunter Ortis of Equine Medical Services Inc. in Columbia, Missouri.
Your veterinarian needs to take a radiograph of the injured leg to accurately diagnose a splint bone fracture. If a tear in the suspensory ligament is also suspected due to the initial trauma, your vet may recommend an ultrasound check of the ligament to determine whether damage has occurred.
Treatment
Most fractures of the lower splint bone heal on their own with a four- to six-month rest, say veterinarian Ronald Riegel and certified medical investigator Susan Hakola in "Illustrated Atlas of Clinical Equine Anatomy and Common Disorders of the Horse." Many equine vets recommend a relatively simple surgical procedure to remove the small bone fragments of this uncomplicated break. Surgery narrows the recovery time and eliminates the possibility of a callous forming over the break, impinging on the suspensory ligament and causing future lameness. After the procedure, vets apply a pressure bandage for at least three weeks. The animal rests in its stall until the sutures are removed, and then the horse is hand-walked for two weeks before returning to light work.
The more complicated upper splint bone fracture may require surgical casting and internal fixation using a bone screw. This type of surgery calls for 60 to 90 days of stall rest and 30 days of hand-walking before resuming light workouts, say Riegel and Hakola.
Most veterinarians prescribe systemic NSAIDS--non-steroidal anti-inflammatory medications--and alternating hot and cold therapies until the initial inflammation subsides. Animals that need surgery or that have open wounds need antibiotics to prevent infection.
Prognosis
A horse recovering from a fractured splint bone often returns to its previous level of work after completing veterinary treatment and taking time off, making the prognosis for such animals very good, reports Mark Georgetti in his article "Understanding Splint Bone Fractures" on the Horse and Hound website. The time off work is much longer and the incidence of recurring lameness considerably higher when the trauma involves the horse's suspensory ligament.
References
- MyHorse.com: Splints and Splint-Bone Fractures in Horses
- "Practical Guide to Lameness in Horses"; Ted S. Stashak, Cherry Hill; 2003
- Equine Medical Services Inc.: Splint Bone Problems - Splints, Pops and Fractures
- "Illustrated Atlas of Clinical Equine Anatomy and Common Disorders of the Horse, Vol. 1"; Ronald Riegel, DVM; Susan Hakola, BS, RN, CMI; 2001
- HorseAndHound.co.uk: Understanding Splint-Bone Fractures
