Fracture of the Pelvis in Cats

Pelvic Fractures in Cats

Fractures of the pelvis are the most common fractures seen in veterinary medicine. These fractures are usually the result of major trauma.

Generally, pelvic fractures cause acute, non-weight bearing lameness of the hind legs. These fractures are usually found in mature bones; young animals with trauma to the pelvis commonly will have other structures break before the pelvis. Because of the shape of the pelvis, these fractures normally occur in several locations at once including both the left and right sides at the same time.

Depending on the nature of the fracture, different methods of management may be indicated in each situation. Pelvic fractures can have serious complications if not repaired or if the repair fails.

Diagnosis of a Fractured Pelvis in Cats

A thorough physical examination can help determine which tests to perform. Although no laboratory tests are required to make the diagnosis, your veterinarian may recommend the following:

• Chest radiographs to rule out injury to the lungs caused by the trauma
• Complete orthopedic examination for other fractures or joint injuries
• Neurologic examination of the hind legs to rule-out nerve damage
• Radiographs of the pelvis

Treatment of a Fractured Pelvis in Cats

Emergency care for concurrent problems caused by the trauma is paramount. Once stabilized, additional treatments can begin.

• Treatment of concurrent soft-tissue injuries
• Anesthesia and surgical stabilization of the bone fragments to give the animal the most rapid and least painful return to function. Some fractures do not require surgery.
• The pelvis cannot be adequately immobilized in a cast or splint to allow proper healing.
• Injectable analgesics (pain medications) are given to the animal while being treated in the hospital and may be continued orally once discharged from the hospital.

Home Care and Prevention

Take your pet to the veterinarian as soon as possible after any trauma for immediate attention. If your animal does not need surgical stabilization or if surgery is decided against, strict exercise restriction may be the only required course of action.

If surgical repair of the fracture is performed, the animal will be kept restricted from activity for several weeks and the skin incision will be monitored while healing.

Recheck appointment with the veterinarian will occur in several weeks to evaluate how the bone is healing (with new radiographs), to monitor the animal’s progress, and to make sure it is safe to increase the cat’s activity level.

Many traumatic events are true accidents and thus unavoidable. Avoid the chance for motor vehicle trauma by keeping your cat indoors where it is safe.

In-depth Information on Fractured Pelvis in Cats

Of all of the fractures seen in small animal hospitals, fractures of the pelvis are the most common. Motor vehicle trauma is the most frequent cause of pelvic fractures. These animals tend to be young, non-neutered males who roam away from home and get hit by a car. Cats of both sexes and of any age are susceptible to this type of trauma if not kept indoors.

The left and right halves of the pelvis are actually several bones that fuse together as the animal matures. Each half is composed of the ilium, ischium and pubis. Both halves are then fused together in the middle to create a boxlike shape. Because of this configuration, trauma to the whole box usually results in many fractures at once. The pelvis forms a “socket” (acetabulum) of the hip joint and connects to the spine through the sacroiliac joints. These joints frequently become involved (fractured acetabulum or sacroiliac luxation) with trauma to the pelvis and may complicate the method of treatment and the animal’s prognosis.

Each case of pelvic fractures needs to be evaluated in its entirety, including the severity of the fractures, age of the cat, experience of the surgeon, and financial concerns of the owner, to determine the most appropriate and best form of treatment.

Inappropriate case management, inadequate surgical stabilization, or poor aftercare can lead to complications such as non-unions (fractures that will not heal), malunions (fractures that heal in an abnormal direction or orientation). These can result in compromise of the width of the pelvic canal, osteomyelitis (bone infection), arthritis of the hip joint, or a non-functional leg.

Diagnosis In-depth

No laboratory tests are required to make the diagnosis, but your veterinarian may recommend the following:

• Thorough physical examination. It is very important to make sure your pet is not showing signs of hypovolemic shock, which is shock due to reduced blood volume, secondary to the trauma or blood loss. It is also important to make certain that there are no other injuries present. A digital rectal examination should be performed to make sure that sharp bone fragments within the pelvic canal have not also injured the rectum.
• Thoracic radiographs (Chest X-rays). Chest trauma, in the form of pulmonary contusions (bruising) or pneumothorax (collapsed lung lobes secondary to free air within the chest cavity), must be ruled out with chest radiographs prior to anesthesia to repair the leg.
• Complete orthopedic examination. A complete orthopedic examination must be performed to look for the cause of the non-weight-bearing lameness as well as possible injuries in other bones or joints. Examination involves palpation of all of the bones and joints of each leg for signs of pain or abnormal motion within a bone or joint. The thorough orthopedic examination is especially important for an animal that is unable or unwilling to get up and move. Crepitation, which is the abnormal “crunchy” feeling with motion, and pain during manipulation of the hip joint(s) may be the only abnormal findings. They do not specifically indicate that the pelvis is broken, but they may help to direct the veterinarian to radiograph the pelvis to look for possible injuries in the hips or pelvis.
• The neurologic status of each leg must also be assessed before any surgery is considered. The sciatic nerves are extremely important to function of the hind legs and they travel very close to the bone on their way to each leg. They can become damaged during the trauma and may alter the recommendations for treatment if present.
• Radiographs (x-ray) of the pelvis. Two radiographic views of the cat’s pelvis are used to confirm the diagnosis of pelvic fractures and may also show sacroiliac luxation (dislocation), coxofemoral luxation, or femoral fracture if they are present. Based on the location and severity of the fracture, a more informed discussion with the owner can occur regarding potential treatments, prognosis and costs.

Treatment In-depth

• Emergency care for concurrent problems. Shock is a frequent result of major trauma and must be treated quickly. Treatment for shock involves intravenous fluid administration to maintain blood pressure and adequate oxygen delivery to the body. Injury to the lungs and chest cavity are also commonly seen after major trauma and may require supplemental oxygenation or removal of free air (pneumothorax) from around the lungs.
• Soft-tissue injuries must be addressed in order to minimize the chance for the development of wound infections. Lacerations and other open wounds or open fractures must be cleaned of debris and covered or closed to minimize infections.
• In the interim between treating the emergency patient and surgical repair of the pelvic fracture, all of the orthopedic injuries that have been found should be addressed with splints and/or pain medications to keep the animal comfortable until the fractures can be properly addressed.
• Depending on the specific fracture type, location, and age of the animal, pelvic fractures may be managed in one of two ways. Some pelvic fractures may not need surgical stabilization. Minimally displaced fractures that do not involve the hip joint might fit into this category. Most other pelvic fractures should be stabilized in order to give the animal the best chance for a successful outcome, with the quickest return to function and the least painful recovery period.
• For most situations of pelvic fractures that do not involve the acetabulum, a bone plate and screws are usually used to support the fractured ilium. Fractures of the ischium and pubis are usually not repaired. Fractures that do involve the acetabulum may need to have the acetabulum carefully reconstructed and stabilized or a procedure in which the femoral head and neck are cut off the shaft of the femur might be recommended. This procedure is done in order to minimize the chance for the animal to have long-term problems associated with a hip joint that heals in an abnormal way leading to future arthritis. If a sacroiliac luxation is also present, the luxation may require repair and stabilization as well. When both sides of the pelvis are broken, only one or both sides may require surgical repair.
• Pelvic fractures cannot be adequately stabilized with a cast or splint.
• Pelvic fractures, as well as any other traumatic injuries that the animal might have, are painful and the animal will be given analgesics before and after surgery.

Follow-up Care for a Fractured Pelvis in Cats

If it is determined that surgery is not required for your pet or if it is not necessary to pursue the surgical option, you must strictly confine your cat to allow the pelvis to heal and prevent excessive pain. Because the bone fragments are not stabilized when this course of treatment is followed, excessive motion or activity can prevent the fracture from healing at all or cause it to heal in a location that interferes with motion of the leg or with structures that pass through the pelvic canal like the colon, urethra and uterus.

After surgery and discharge from the hospital, the animal must be restricted from activity to allow the fracture to heal properly. Activity must be restricted for several weeks after surgery (the duration will vary depending on the severity of the injury, the type of fixation that was used, and the age of the animal). Restricted activity means that the animal should be kept confined to a carrier, crate, or small room whenever he cannot be supervised, the animal cannot play or rough-house, even if he appears to be feeling well, and the use of stairs should be limited.

Analgesics (pain medications) or anti-inflammatory drugs should be given as directed by the veterinarian. Analgesics, such as butorphanol (Torbugesic®) can cause sedation, and anti-inflammatories, such as aspirin or carprofen (Rimadyl®), can cause an upset stomach. Your veterinarian should be informed if any adverse side effects do occur.

The skin incision needs to be monitored daily for signs of excessive swelling or discharge. These can indicate problems with the incision or possibly infection. Contact your veterinarian if these occur.

If at any point prior to the recheck radiographs your pet stops using the leg again after some improvement following surgery, there could be a problem. Again, the veterinarian should be notified.

Several weeks after surgery, the pelvis will need to be radiographed again to make sure the bones are healing well. If the healing has occurred as expected, the cat’s activity level will be allowed to increase slowly back up to normal over the next few weeks.

In general, any other implants that were used in the repair will be left in place unless they cause the animal a problem at some point in the future. Potential problems can include migration (movement) or infection of the implant.