Traumatic Bone Injuries
TRAUMATIC BONE INJURIES
When it comes to fractures we prefer to say, "we don't shoot horses anymore." While "shooting a horse" with a broken bone was common practice back in the olden days, that same horse can often be saved today. Much of the decision to treat the patient is based on the cost of treatment, the value of the horse, the availability of insurance support, and the prognosis for a return to soundness. Some of the fractures are such that treatment is difficult without extreme measures, or recovery is possible but would result in an unsound horse. Let us be a little more specific about these conditions.
Fractures of the long bone of the legs below the knee and hock can be repaired with a good prognosis. Stabilization with a cast for six weeks will usually result in a well-healed bone. Other than the challenge of building a cast that will withstand the weight of the patient, the prognosis is good and the cost is reasonable.
The exception to this is the compound fracture. A "compound fracture" is when there is an open wound at the site of the fracture, either from the incident causing the injury or from the end of the bone pushing through the skin. This allows infection into the bone and the soft tissue surrounding it. Antibiotic treatment must be continuous and at very high levels, which can be difficult with the injury enclosed within a cast. Recent advances have been made, making it possible to route antibiotics to these areas.
Unless healing is delayed and a large bone callus (similar to a scab) forms at the site of the fracture, there should be little arthritis (click for more on arthritis). If the extra callus does form, there can be some arthritis where the tendons move over this rough area. It is similar to sand or small rocks (in the worse cases) in our shoe: they are present and very irritating. Usually a small amount of anti-inflammatory medicine such as phenylbutazone or aspirin will mask the discomfort and allow use of the horse.
If there is a fracture of the long bone above the knee or hock, treatment becomes much more involved. The difficulty in treating these fractures is due to the challenge of stabilizing the fracture site. Stabilization of a fracture site involves limiting movement of the joint above and below the fracture:
In the front leg, repair of a fracture of the radius would require stabilization of the knee and the elbow.
A fracture of the tibia of the back leg would require putting the hock and stifle in a cast or stabilizing apparatus. The knee and hock can be surrounded with casting material, but the elbow and stifle cannot.
A fracture of the humerus and shoulder blade of the front leg, or of the femur of the back leg, presents even more challenging situations. As you can imagine, many of these cannot be saved without considerable treatment and expense, if at all:
With the humerus, shoulder blade, and pelvis, conservative treatment may be successful.
We have a mare at the clinic right now that fractured her humerus (the large bone of the upper front leg) many years ago.
~For lack of any practical approach, and due to her owner's willingness to go to the greatest of lengths to save one of his horses, we just let her carry that leg.
~The weight of the leg kept the bone ends together and the pain of the fracture kept Cricket from moving.
~That has only been about fifteen or more years ago (my memory only goes back that far!), and she moves without any indication of a past fracture.
In fact she feels so frisky she is going to be bred.
Most horses are not this fortunate, and the movement of the unrestrained leg prevents the fracture from healing. In addition, the opposite leg will often break down due to the increased weight it must bear. If the fracture does heal, it usually takes longer due to the movement that does occur and the thickness of the bones involved. These conditions result in more bone or callus buildup, and the presence of rough bone or arthritis.
Next week we will discuss fractures of the small bones and the bones forming joints.
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