Feline Fracture Repairs
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.
The majority of fractures in cats 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
Sudden onset of lameness
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.
Diagnosis of Fractures in Cats
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.
Treatment of Fractures in Cats
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.
In-depth Information on Fracture Repair in Cats
Below are some conditions and concerns that can be related to fractures in cats.
Any swollen and painful area of an extremity may be confused for a fracture, particularly if your cat will only allow a cursory examination of the injured limb. A swelling may be due to an infection, cyst, tumor, abscess or hematoma.
Dislocations of joints can produce profound lameness that can be misinterpreted as a potential fracture. Certain dislocations or luxations may give rise to more characteristic placement of a limb. For example, a dislocated hip may give rise to positioning of the paw beneath the body with the knee outwardly rotated. This would be quite different from a femur fracture that might just “dangle” from the body.
Fractures may go unnoticed in cases with multiple injuries, for example, a cat with an obvious fracture of a radius and ulna may also have a subtle scapula fracture which is easy to overlook.
Many fractures can have significant effects on other organ systems that need to be taken into consideration, such as pelvic fractures causing urethral trauma, spinal fractures causing spinal cord injury and rib fractures causing lung trauma.
Some traumatic injuries to bone create crushing or shearing forces on the growing areas of young bone, the growth plates. Such damage does not always result in overt fractures or changes on a x-ray, directly after the trauma. The interference with the growth plate may take weeks to create a visible change in the shape of the limb or to produce an abnormality detectable on an x-ray.
Treatment In-Depth of Injuries in Cats
Following a traumatic injury, fractures will be low down on the list of priorities for your cat in comparison to bleeding problems and breathing disorders. Life threatening problems will be evaluated and treated initially.
For this reason, all fractures of the extremities will be noted on a thorough examination but will be addressed once other systems are stable. Fractures associated with the skull and the spine may necessitate careful handling of your pet and modifications of early treatment protocols to offset spinal cord or brain swelling. Once stabilized, tests and treatment may include:
Open wounds with protruding bone fragments will be covered and protected. Antibiotics will be started until the area can receive some form of temporary stabilization.
Careful physical examination will usually allow localization of a suspected fracture due to the pain produced on palpation of the area or the restriction of range of motion in that region of a limb.
The bones of the jaw and skull will be examined to evaluate dental alignment, jaw motion, nasal deviation and the presence of swollen or depressed contours of the skull where fractures may have occurred.
If your cat is recumbent (lying down and unable to get up), a neurological examination will be performed to evaluate the cranial (head) nerves, consciousness and reflexes of the forelimbs and hindlimbs. Any abnormalities may be suggestive of skull or spinal fractures or spinal dislocations.
Radiographs (X-rays) are the mainstay of fracture diagnosis. Before X-rays are taken of the limbs, blood work, chest and/or abdominal radiographs may be more important to ensure that vital systems are in order and to assess your pet’s risk for anesthesia, if surgery were necessary.
Chest and abdominal X-rays may provide valuable information with regard to rib fractures, spinal injuries and some upper forelimb and hindlimb fractures that happen to be included on the film.
Only when your cat is stable will views be taken specifically to evaluate the nature of a fracture. This may be done prior to anesthesia or under anesthesia as certain views may be difficult to obtain in a conscious and painful animal.
Based on the type of fracture(s) present your veterinarian will present options for treatment. This may include referral to an orthopedic specialist.
Use of CT scans or MRI is occasionally helpful for the diagnosis of fractures, particularly involving the skull or spine to assess involvement of underlying nervous tissue.
Special radiographic views, such as skyline views or oblique views, can be used to highlight certain fractures and experienced radiographers may be needed to obtain these images.
Treatment In-Depth of Fractures in Cats
The type of fracture, its location, the age of the animal, the presence of other injuries/fractures and the financial means of the owner are all major considerations in the choice of fracture repair undertaken. For any given fracture there are often many different treatment options.
Some types of repair may require special equipment and experience and your veterinarian may recommend referral to a board certified surgeon.
Because there are many ways to fix the same fracture. Each option will be discussed and considered for its advantages and disadvantages in the context of your cat and his or her particular injury/injuries.
The Robert Jones bandage is the most common form of temporary fixation of a fractured limb prior to definitive stabilization.
Casts and splints are usually the easiest and least expensive ways to provide stabilization of a 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.
Casts and splints may not be appropriate for open fractures, in which the bone has pierced the skin or where there is a lot of soft tissue trauma associated with the broken bone. Casts prevent management and monitoring of the injured area.
External fixation can provide stable fracture fixation at less cost than plates and screws. It can be particularly useful for the management of open fractures or fractures where wounds need to be managed while the fracture is stabilized.
External fixators in many cases can offer the surgeon the ability to stabilize a fracture, without interfering with the natural healing process already under way. Closed reduction involves manual repositioning of the broken bones, placement of pins through the skin and into these bones and then rigid fixation of the pins to metal bars, graphite bars, circular rings, or cement polymers.
External fixators can be simple or complex creating uniplanar, biplanar, and circular support frames around the fracture. The fixators may appear cumbersome and uncomfortable but cats tolerate them extremely well.
The connection of the pins through the bone to the outer construct may involve clamps that will be checked periodically for tightness.
External fixators may not be suitable for certain fractures where they may interfere with muscles and impede movement of a limb. Generally they are considered less appropriate for fractures of the femur and the humerus.
Internal fixation, by definition, necessitates internal reduction of the fracture, by incising the skin and dissecting through soft tissue planes to get the fragments exposed and back into alignment.
Internal fixation is often appropriate for more complicated fractures such as those that involve a joint surface, or those that have shattered the normal contour of the bone, as in a comminuted fracture.
Stainless steel pins and wire are the simplest implants for internal fixation. Wires (referred to as cerclage wires), can be placed around the circumference of a bone to squeeze together fracture fragments in order to reconstruct the cylinder of bone that used to exist. They can also be used in combination with small pins to skewer bone back into place, particularly where the fractured bone may be pulled away or distracted by a muscular attachment, a so-called tension band wire technique.
Larger pins can be placed down the central canal of a long bone, an intramedullary pin, to enable the fracture fragments to be brought back together.
The pin can provide good resistance against bending of the healing bone but poor resistance to rotation around its long axis. Cerclage wires may help resist this rotational instability but certain fractures may benefit from adjunctive external fixation or the use of plates and screws instead of pins and wires.
Plates and screws offer the most rigid form of fracture fixation and, therefore, early return to limb function. There are numerous different sizes and shapes of plates and screws for different sized animals and fracture configurations. Plates and screws tend to be the most expensive form of internal fixation.
When fractures involve a joint surface, screws can be used to put the bone fragments into apposition and to actually compress them together, thereby minimizing any gap or step at the fracture site. This will restore the fractured bone as close to normal as possible, allowing optimum function of the joint and minimizing the chances for arthritis.
Metal plates can be used to span the bone across a fracture site. The plate can be used to hold the fragments in place or to actually squeeze and compress the ends of the bone together to enhance and speed up the healing process. Many of the plates are designed in such a way that when a screw is placed through its appropriate hole in the plate and screwed into the bone, it will compress the ends of the fracture fragments together – a dynamic compression plate. Ideally, a surgeon will attempt to get at least three screws above and below the fracture site.
Plates and screws can be used in conjunction with pins and wires and external fixators, depending on the configuration of the fracture that is being repaired.
Interlocking intramedullary pins are popular in human orthopedics, and are becoming more common in veterinary surgery. This technique combines placement of a pin down the medullary (central) cavity of a bone and screwing this pin into the bone at several locations along its length. It is mainly used for the treatment of humeral and femur fractures.
Spinal fractures and combinations of fracture and dislocation, where spinal cord is damaged, are the only fractures that constitute a surgical emergency. Fixation of these fractures can be achieved using any of the techniques previously described, including the use of pins fixed in position using a sterile cement compound.
Follow-up Care for Cats with Fractures
The cast or splint needs to be kept clean and dry. The top of the cast may have a tendency to rub or chaff the skin. The toes at the bottom will need to be assessed for swelling, sweating or pain. Sore areas will necessitate that the cast is changed. The cast may have fitted snugly at the time of initial placement but because the swelling at the fracture site resolves, the cast may become loose.
Casts and splints may seem like the least expensive option but cast complications that necessitate numerous changes can add up, particularly if sedation or anesthesia is required to change a cast. In many cases, other forms of fixation may not actually cost that much more.
The skin-pin interface of an external fixator will need attention to keep the area clean and dry as discharge and crusting commonly occur at these sites. Sometimes pus will be noticed at this interface and is not uncommon. You should consult with your veterinarian to ensure that the discharge is reasonable and to be expected.
External fixators may not be appropriate for some pet owners who find the devices distasteful to look at and manage.
Cats must be restricted and confined when wearing an external fixator as it is possible to snag the device on furniture or other household items if the pets are given too much freedom.
When internal fixation has been performed, there will be a surgical incision which will have to be checked daily for swelling, redness and discharge. Stitches or staples will need to be removed in 10 to 14 days following surgery.
All animals that are recovering from fracture repair surgery or are in a cast or splint will need restrained activity: they should be confined to a small area; going up or down stairs (unless unavoidable) should not be allowed; they should not be allowed to jump on and off furniture; and they must be kept indoors.
The fracture will be re-evaluated and x-rayed again by your veterinarian from 4 to 8 weeks after the surgery or cast placement, depending on the nature of the fracture and the age of your pet. Young kittens heal quickly and may have cast removal after only a few weeks, whereas older debilitated animals may not heal properly for months.
The external fixator may be removed in stages in order to increase the work of the healing bone that has been stabilized. This can involve removal of a couple of pins at a time over a number of weeks until the device is fully removed. The holes where the pin was removed should be kept clean until they dry up and scab over. Infection tracking along a pin and into the underlying bone is extremely unusual.
Most plates, screws, pins and wires can remain in place if they are not causing a problem. If they are backing out or migrating from the bone they will usually cause swellings, pain or lameness and should be removed. This may require sedation or a general anesthesia.