Fracture of the Metatarsus and Metacarpus in Cats

Fracture of the Feline Metatarsus and/or Metacarpus

The metatarsal bones are the long bones in the hind foot (the arch of the human foot) that connect the toes to the bones of the ankle (tarsus). The metacarpal bones are the long bones in the front foot (the human palm) that connects the fingers to the bones of the wrist (carpus). Fractures of these bones usually occur as the result of major trauma in cats.

These fractures can be classified as “open” (bones exposed) or “closed,” and can be “simple” or “comminuted” (multiple fragments). Depending on the nature of the fractures and the age of the animal, different methods of repair may be indicated for each situation.

Metatarsal and metacarpal fractures generally heal well without long-term effects on the cat, but they can lead to abnormal function of the foot if not properly treated.

What to Watch For

• Lameness
• Swelling of paw
• Pet not putting weight on the paw
• Pain when paw is handled

Diagnosis of Metatarsal and Metacarpal Fractures in Cats

A thorough physical examination is important to determine if fractures are present and to determine if there are other injuries. No laboratory tests are required to make the diagnosis, but your veterinarian may recommend the following:

• Complete orthopedic examination
• Radiographs of the affected foot
• Chest radiographs to determine other injuries

Treatment of Metatarsal and Metacarpal Fractures in Cats

Emergency care for concurrent problems caused by the trauma is the most important part of treatment. After stabilization, additional treatment may include:

• Cast or splint. Certain fractures of the metatarsal and metacarpal bones can be managed successfully with a cast or splint.
• Surgery. For some fractures, anesthesia and surgical stabilization of the bone fragments may be recommended.
• Pain medication. 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

After surgical repair or immobilization in a cast or splint, the cat will require restricted activity for several weeks and the cast or splint will need to be kept clean and dry.

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

Most metatarsal and metacarpal fractures are caused by trauma and since many traumatic events are true accidents, they are often unavoidable. Keeping your cat confined to a fenced in area or leash walk only can help prevent some traumatic events.

In-depth information on Feline Metatarsal and Metacarpal Fractures

In cats, there are four metatarsal bones in each hind foot and five metacarpal bones in each front foot. In the front foot, the dewclaw is a rudimentary “thumb” that has a metacarpal bone associated with it, but it does not reach the ground and has no function. The other four metacarpal bones and all of the metatarsal bones run parallel to each other and commonly more than one of the bones in the foot will fracture at the same time.

The middle two toes on each foot are considered the “weight bearing” digits because they support most of the weight. The outer two toes on each foot bear less weight and are considered the “non-weight bearing” digits. Fractures that involve only the non-weight bearing digits tend to cause less lameness for the animal than those that involve the weight bearing digits.

Fractures of the metatarsals and metacarpals can be classified as “open” or “closed” depending on whether the skin surface has been damaged during the injury. Open fractures have a greater chance of getting infected and may have more complications than closed fractures. Open fractures of the feet are common as there is little soft-tissue covering these bones.

As with all fractures, fractures of the bones of the feet can also be classified as “simple,” if each bone breaks into two pieces, or “comminuted,” if there are multiple pieces.

Each case of metatarsal and metacarpal fracture needs to be evaluated in its entirety (age of animal, severity of the fracture, 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), osteomyelitis (bone infection), or a non-functional foot.

Diagnosis In-depth

A thorough physical examination is very important to make sure your pet is not showing signs of hypovolemic shock secondary to the trauma or blood loss. It is also important to make certain that there are no other injuries present. Additional tests may include:

• 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 as well as an assessment of the neurological status of each leg. The thorough orthopedic examination is especially important for an animal that is unable or unwilling to get up and move on the other three legs. Specific palpation of the foot and finding swelling, bruising, pain, and crepitation (abnormal “crunchy” feeling with motion) can be highly suggestive of fractures of the metatarsal or metacarpal bones.
• Radiographs of the foot. Two radiographic view of the animal’s foot are used to confirm the diagnosis of metatarsal or metacarpal fractures. Based on the location and severity of the fracture, a more informed discussion with the owner can occur regarding potential treatments, prognosis and costs.
• No laboratory tests are required to make the diagnosis.

Treatment In-depth

Emergency care for concurrent problems is paramount. 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. Once stabilized, additional treatment may include:

• 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 stabilization of the metatarsal or metacarpal fractures, all of the orthopedic injuries that have been found should be addressed with splints and/or pain medications to keep the animal comfortable.
• Depending on which bones are fractured, how many bones are fractured, and the age of the animal, metatarsal and metacarpal fractures may be repaired in a few different ways. If at least one of the weight bearing bones is not fractured, the foot may be treated without surgery by immobilizing the foot in a cast or splint. The remaining unbroken bones act as internal “splints” that help to maintain alignment of the fractured bones. For those fractures that involve both of the weight bearing bones and especially those that involve all four bones in the foot, surgical stabilization will likely be recommended. Depending on the size of the animal’s bones, pins alone, pins and wires, or bone plates and screws can be used to provide stability to the bone fragments while they heal. After surgical repair, the foot is usually placed in a splint to protect the small implants while the bones regain strength.
• Fractures of these bones in the feet, as well as any other traumatic injuries that the animal might have, are painful and the cat will be given analgesics before and after surgery.

Follow-up Care for Cats with Metatarsal and Metacarpal Fractures

After discharge from the hospital, the cat must be restricted from activity to allow the fracture time to heal properly. Activity must be restricted for several weeks after surgery; the duration will vary depending on the severity of the injury and any concurrent injuries the animal may have. Restricted activity means that the animal should be kept confined to a carrier, crate, or small room whenever he cannot be supervised. Playing and rough-housing should be avoided, even if he appears to be feeling well. The use of stairs should be limited, and outdoor walks should be just long enough for the cat to relieve himself and then should be returned indoors for more rest.

The cast or splint must be monitored closely during the recovery period. If it becomes wet or soiled, it should be removed and replaced with new materials. The end of the foot should be covered with a plastic bag when the cat is taken outside to keep it from becoming wet. When brought back indoors, the bag must be removed. The toes that may be visible at the tip of the bandage should be watched for swelling, discharge or odor. If the cat begins chewing at the cast or splint, there might be a problem that should be checked by the veterinarian. Generally, the veterinarian will want to check or change the bandage materials regularly to make sure that there are no hidden problems and that the cat is progressing well.

Analgesics (pain medications) or anti-inflammatories 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.

If surgery was performed, there will be a skin incision that will be concealed by the bandage. Your veterinarian will check the incision and remove any sutures at one of the follow-up appointments.

If at any point prior to the recheck radiographs being taken the dog stops using the leg again after some improvement following surgery, there could be a problem.

Several weeks after surgery, the foot will need to be radiographed again to make sure the bones are healing properly. If the healing has occurred as expected, the cast or splint may be replaced with a less supportive soft-padded bandage, or may be left off altogether, and the dog’s activity level will be allowed to increase slowly back up to normal over the next few weeks.

In general, any 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 implants.