When a horse breaks a leg, many people assume it basically means death. However, with improvements in pre-, during and post-operative care, euthanasia is not always the end result. The equipment has improved, and there are more accredited surgeons that are well trained. Anesthesia techniques have been refined and recovery facilities updated to better help the animal when it first wakes up. Today, the survival of the horse is often more a case of finances rather than the veterinarian’s ability to save the animal.
Factors to Consider
Microfractures in the bone are common responses to exercise stress. If given enough time between stressful events, the bone will repair, reinforce and remodel itself. Bone remodeling, which can take place within the bone or on its surface, continues well into a horse’s adult life. However, if the bone isn’t given time to mend, it can eventually lead to a break.
Even with all the recent veterinary advances, fractures in horses are more difficult to repair, and take longer to heal, than human or small-animal fractures. The horse is a large animal and must bear weight on the injured leg immediately, or adapt to being in a sling. Laminitis in the opposite good leg is always a possibility.
Different types of bone heal differently, depending on the range of motion and distance between fragments. However, bone does heal faster than tendons or ligaments, and it heals to 100 percent of its previous strength.
When the Leg Breaks
If you are present when the worst happens, you may hear a loud pop or crack when the bone cracks. Swelling and significant pain quickly follow, and the horse will be unable to bear weight on that leg. Veterinarians have found that a successful recovery has a lot to do with what happens before surgery. The cleaner and more immobile the fracture is, the better. Horses that continue to move on a broken leg can splinter the bone into many pieces, tear soft tissue, and disrupt or destroy blood flow to the leg.
When trying to support the leg until help is available, it is important to keep the bones in a straight line. Racetracks, and perhaps other large equestrian facilities, have equipment on hand to quickly help immobilize a fracture. But even if you don’t, it is possible to create a splint on your own. For the AAEP, Dwight Bennett, DVM, PhD, describes the following steps to safely splint a horse’s leg:
1. Apply a bandage. Never place wood or other stiff splinting material directly against the horse’s skin. Instead, place a bandage under the entire length of the rigid splint.
For a fracture at the fetlock or below, apply a single layer of roll cotton over the skin. Wrap gauze smoothly and tightly over the cotton, then wrap it with elastic tape.
A fracture that lies from mid-cannon-bone upward requires a Robert Jones bandage, which consists of several one-inch layers of cotton bandage. Individually cover each layer with gauze and elastic tape, and repeat until the total bandage diameter is approximately three times the limb’s diameter.
2. Apply the splint. Any lightweight, relatively strong, rigid material, such as wood or PVC pipe split lengthwise, makes an effective splint. Place the rigid material over the bandage and tape it in place with nonelastic adhesive tape. A proper splint requires two boards or two pieces of PVC tubing placed 90 degrees apart—never 180 degrees. In other words, one board should lie along the outside of the leg, and the other should lie along the front or the back of the leg. This helps prevent the leg from bending in any direction.
Types of Fractures
There are three basic types of fractures. The first is an incomplete fracture, where the bone splits but doesn’t break into separate pieces. In contrast, a complete fracture happens when the bone separates into pieces, but doesn’t break the skin. A simple complete fracture breaks into two pieces; a comminuted one breaks into more than two pieces. Finally, a compound fracture is a complete fracture that breaks through the skin.
A minor incomplete fracture may be difficult to diagnose, because the horse may initially display only mild lameness. However, if the horse continues to use the injured limb, the break could become much worse. Radiographs and nuclear scintigraphy help diagnose hidden fractures that, if caught early, may heal with just stall rest.
Performance horses incur a number of different types of breaks. Elizabeth Davidson, DVM, Diplomate, ACVS, Assistant Professor in Sports Medicine at the University of Pennsylvania’s New Bolton Center, mentioned patella (kneecap of the stifle) fractures and coffin bone (P3) fractures as two of the more typical ones. Patella fractures are most often seen in upper-level event horses that are traumatically injured when they hit the front of their stifle on the jump. The key to successful treatment of stifle fractures, Davidson says, is appropriate early diagnosis. However, the stifle is “a difficult area to radiograph. You need multiple views and non-conventional views.”
Once diagnosed, surgical intervention is required. A small fracture with bone chips can be treated arthroscopically, but large fractures are usually fixed with screws inserted through the bone. Both types of surgeries are challenging because of the location. Therefore, Davidson recommends that an experienced orthopedic surgeon do them.
The prognosis for patella fractures is fair to good if treated quickly and appropriately. “A large factor is recovery,” says Davidson. If a small fracture is identified quickly and treated with removal of the chips, many horses can return to their previous level of activity. “But it will be a long rehab,” cautions Davidson. “There will be months of rest to allow the soft tissue and bone damage to heal. For a 3- or 4-star event horse you are looking at a year of rest and rehab before the horse is ready to return.” Larger fractures have a poorer prognosis because there is usually more soft tissue and joint damage. It is also more difficult for the horse to bear weight on the leg, which will mean a long and slow process and, if the horse recovers, chances are he will not return to the same level he was at.
Coffin bone fractures come in several varieties, including sagittal (which are straight down the bone) and wing (in which the side part chips off the bone). Wing fractures may be either articular (involving the joint surface) or non-articular. For non-articular fractures, Davidson recommends stall rest and bar shoes with side clips. The area should be radiographed after 6 to 8 weeks to see how the healing is progressing. Coffin bone fractures are slow to heal, and may require up to 6 months of stall rest. However, with proper rest and shoeing, the prognosis for recovery is very good.
Articular wing fractures have a worse prognosis. Even if they heal, the horse may develop arthritis within six months to a year. The surgical option of a neurectomy is a last resort, but it “needs to be considered seriously.” It does not fix the problem, but stops the horse from feeling pain.
Complete fractures, while rare in performance horses, require surgical repair. The bones must be properly aligned and fixed into position via a cast, pins, screws or plates until healed. Plates sandwich the bone, whereas pins and screws pass through the bone both above and below the fracture. These fixtures may be permanent or require a second operation to remove them. Long bone fractures of the forearm, shoulder or hind leg have a poor prognosis because these are major weight-bearing bones.
While there still is no simple cure for a major break, many of the milder fractures and smaller breaks can be treated successfully through modern surgery and good post-operative care. As with most health issues, the trick to giving the horses in your care the best chance of recovery is to catch the problem early on, get it treated effectively, and patiently attend to the details of recovery.