Fracture Repair in Cats
Dr. Nicholas Trout
A fracture is any break in bone or cartilage, whether it is complete or incomplete. With any fracture there is also damage to the surrounding soft tissues. Sudden onset of lameness
The majority of fractures are caused by trauma sustained by motor vehicle accidents. Occasionally they will occur because of an underlying bone disease such as a bone tumor or from repetitive stress applied to a certain bone.
Because trauma is the most common reason for fractures, young, male non-neutered cats, may be at a higher risk as they are more prone to wander and to get into trouble.
What to Watch For
Swelling or pain associated with touching an area of the body
Bone sticking through the skin
A fracture may be an incidental finding among other more serious and life threatening injuries following trauma.
In many cases, a history of trauma will be obvious, but your veterinarian will carefully question you about the events leading up to the fracture. For example, a fracture in an older cat, secondary to minimal trauma, say slipping on a floor, may suggest underlying weakness in the bone, perhaps a fracture secondary to a bone tumor.
There may be swelling and pain associated with a fracture, together with instability and crunchiness on palpation. 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 addition to a 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. This can be done closed, that is without exposing the bones, using traction and manipulation, trying not to disturb the natural healing processes already underway. Or, it can be done open, surgically exposing the bones by separating and, if necessary, cutting through muscle to visualize the fracture and to put it back together. Both techniques require general anesthesia.
The fracture must be immobilized to allow it to heal and this can be done in several ways.
A limb can be placed in a splint or cast, which aims to immobilize the joint above and below the fracture. Nowadays, casts tend to be made of fiberglass. This technique is not particularly useful for fractures above the stifle or above the elbow.
External fixation describes the use of pins passed from outside the leg, through the skin and into the bones of the limb, ideally with at least three pins above and below the fracture. These pins can then connect to one another either by bars, or rods or cement or rings. External fixators can be applied open or closed, and combined with many other techniques making them extremely versatile.
Internal fixation describes the use of pins and wire, plate and screws, with variations on these themes, such as interlocking nails placed via open reduction of the fracture. Plates and screws can be used for a variety of different fragments, but offer exceptionally stable fixation and in some cases the ability to squeeze or compress the ends of the bone fragments together. Such repairs can ensure an animal can be up and using a fractured limb as soon as possible.
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.
External fixators must have the skin-pin interface cleaned daily or twice daily, where the pins pass through the skin toward the bone. Crusting and discharge is common at this location, but excessive swelling or discharge should be brought to your veterinarian's attention.
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 (2 to 4 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.
Since most fractures occur secondary to being hit by a car, all cats should be kept indoors whenever possible.