Simple Fracture in Cats
Dr. Nicholas Trout
A simple fracture is a break in the continuity of bone or cartilage with minimal displacement or disruption of the normal structure. The bone is broken into two fragments. Fractures that result in multiple bone fragments are referred to as "comminuted." Young growing animals are most commonly affected by simple fractures. Lameness
Simple fractures usually result from low-grade trauma, such as being stepped on or landing awkwardly during a fall. Cats with inadequate or inappropriate nutrition may be predisposed to simple fractures because poor bone quality may leave their skeletons prone to minor fractures from injuries that would not normally cause a problem. In older cats, simple or spiral fractures secondary to minimal trauma like slipping on a floor may suggest underlying weakness in the bone, perhaps a fracture secondary to a bone tumor.
Simple fractures may cause minimal soft tissue swelling at the fracture site. They can produce a non-weight-bearing lameness or, depending on the fracture location, no obvious lameness problems. In some cases, if not addressed, the bone may heal in an abnormal alignment or not heal at all. If the cause of the fracture is underlying metabolic or nutritional bone disease, this must be addressed to prevent subsequent fractures.
What to Watch For
Limb swelling after a minor injury
A history of trauma may not be obvious, so your veterinarian will carefully question you about the events leading up to the injury. This may include questions about type of diet or the use of dietary supplements.
There may be swelling and pain associated with a fracture, but instability and crunchiness on palpation of the fracture site is uncommon with simple fractures. A leg may be completely non-weight bearing, or in the case of certain pelvic fractures, a cat may use the leg as if nothing has happened.
In most cats with simple fractures, there are no major life threatening injuries and so most patients are stable at the time of presentation. After a thorough physical examination, other tests may include:
Radiographs. X-rays are the most common way to diagnose the presence of a fracture. A fracture may be obvious or very subtle on an X-ray. Sometimes your veterinarian will X-ray the normal opposite side, if possible, to compare to the suspected fracture, in order to confirm the diagnosis.
Blood tests. There are no laboratory tests specific to fractures, but blood may be obtained and tested prior to a general anesthesia, to ensure that there are no other abnormalities.
To repair a fracture, the ends of the bone must be opposed and the continuity of the bone restored as close to normal as possible. In the case of simple fractures, this can often be done closed, that is without exposing the bones, using traction and manipulation, trying not to disturb the natural healing processes already underway. Surgically exposing the bones by separating and, if necessary, cutting through muscle to visualize the fracture and to put it back together, (open fracture repair) may be appropriate for simple fractures above the elbow and knee. General anesthesia is necessary to manipulate a fracture.
The fracture must be immobilized to allow it to heal and this can be done in several ways.
Casts and splints are usually the easiest and least expensive way to provide stabilization of a simple fracture below the elbow and below the stifle. Plaster of Paris® used to be used for casting but it has been replaced by fiberglass materials that can easily and quickly be molded and conformed to the shape of the leg and then set to provide rigid external fixation. Plastic, fiberglass and metal splints in a variety of shapes and sizes can be used to provide support to a portion of the limb, usually the back or the sides, as opposed to a cast that encompasses the entire circumference of the affected portion of the limb.
The rigidity of the cast prevents bending of the limb but the joint above and below the fracture must be stabilized to prevent rotation of the fracture fragments. This limits the use of casts and splints to the lower extremities, below the knee and elbow.
Higher up the leg internal fixation may be used to fix a simple fracture. Most commonly this would involve the use of pins and wire or perhaps plate and screws, placed via open reduction of the fracture.
Injectable analgesics (pain medications) may be given to your pet while being treated in the hospital and may be continued orally once your pet is discharged from the hospital.
In some cases, in which an animal is young and healthy, and the fracture is minimally displaced and relatively stable, strict cage rest for several weeks can allow the fracture to heal.
Home Care and Prevention
In the case of a cast or splint, the toes or the top of the bandage will need to be checked daily for swelling, rubbing or chaffing. The cast or splint will need to stay clean and dry. It may need to be checked and changed frequently to avoid or address pressure sores, particularly the top of the elbow and the knee.
In cases of open fracture repair, there will be an incision that needs to be monitored for swelling redness or discharge. Stitches or staples will need to be removed in 10 to 14 days.
Your pet will need to rest to allow the fracture to heal. This time frame will be less for younger animals (two to four weeks) and longer for older animals (6 to 12 weeks or even more dependent on the nature of the fracture).
Follow up x-rays will be taken with your veterinarian to ensure the fracture is healing and that there are no problems with the implants.
If your pet is being fed an inappropriate diet, it must be changed to a balanced preparation, either homemade (after consultation with your veterinarian) or regular proprietary cat food. This should ensure healthy bone quality and avoid these simple fractures in the future.