Carpal Hyperextension in Cats

Overview of Carpal Hyperextension in Cats

Carpal hyperextension injuries in cats produce a breakdown of the ligaments that support the back of the carpal joint in the wrist resulting in collapse from the normal upright position. The injury can produce a non-weight bearing lameness that progresses to a point that demonstrates the broken-down appearance of the carpus. The lameness usually persists and leads to significant arthritic changes in the affected joints. The carpus is commonly referred to as the “wrist” of a cat.

There is no breed, age or sex predisposition. Most commonly, the disease is the result of landing on the front legs from a significant height such as a second story window.

What to Watch For

Diagnosis of Hyperextension Injuries to the Carpus

Following a thorough discussion of your cat’s medical history and a full physical examination, your veterinarian will perform an orthopedic evaluation.

Treatment of Hyperextension Injuries to the Carpus

Medical management is often unrewarding, so carpal hyperextension injuries are best treated surgically. This involves making an incision over the damaged joint, removing the articular cartilage from the affected joint and other joints nearby to allow the bone across the joint to fuse. The bones can be held in place to allow this fusion to occur (arthrodesis) by a metal plate and screws, pins, or even placed in a cast alone.

Your cat will receive injectable pain-killers (analgesics) during the period of hospitalization, and will probably be sent home with oral medications to reduce pain and inflammation.

Home Care and Prevention

Your cat will usually be in a splint or cast, regardless of the surgical fixation technique. You will need to keep the bandage clean and dry. The toes at the bottom of the dressing should be checked daily for swelling, pain or discomfort.

If the bandage gets wet, creates sore spots at the top or bottom, begins to smell, or seems to bother your cat, it will need to be changed.

Strict rest is important for the first six to eight weeks following surgery. Follow-up X-rays of the surgery will be arranged with your veterinarian to assess the healing, to time removal of the cast or splint, and to set up a program for gradual increase in exercise.

Depending on the type of surgery performed, your cat will not have complete range of motion in the carpus or even no motion whatsoever.

Carpal hyperextension injuries are usually the result of a significant fall from a height. To prevent this, make sure that windows are secure in second floor rooms that your cat can access.

In-depth Information on Feline Carpal Hyperextension

Diagnosis In-depth

Treatment In-depth

Follow-up Care for Cats with Carpal Hyperextension

The toes can be seen at the bottom of the bandage and they may be somewhat swollen, but your veterinarian will guide you as to how much swelling is normal, and when to be concerned. Although swollen, the toes are not normally painful. However, they may sweat and become moist, necessitating cleaning with a moist cotton ball.

The swelling subsides dramatically within the first week, so your cat may require a cast change to enable a better fit and support. Your cat should not place any weight on the limb initially, but he can begin to do so gradually over the next few weeks.

Strict rest is essential, which means no going up or down stairs and no jumping on or off furniture. Avoid slippery surfaces such as tile, linoleum or hardwood floors.

The incision over the front of the wrist and down the paw cannot be seen under the splint or cast. For this reason, look for any discharge seeping through the bandages, any foul smell, or your cat pulling or biting at the bandages. If you have concerns, have the cast checked by your veterinarian. Stitches or staples can be removed 10 to 14 days after surgery.

X-rays of the carpus will be redone around six weeks after the procedure to assess healing. Depending on how things look, the cast may be reduced to a splint, or even a soft padded support bandage for a few more weeks; in this way, slowly downgrading the amount of external support so that the healing fusing bones have to work a little harder. The carpus may be X-rayed again in four to six weeks.

All external support may be removed from eight to 12 weeks depending on the damage, the type of fixation, the age of the cat, and so forth. If the plate or pins are not causing any problems, they can stay where they are. In some cases, pins may back out and need to be removed, or plates, particularly in partial fusion, may impinge on the large radio-carpal joint, and are better off being removed.

In order to create a hyperextension injury to the carpus, a significant downward force must be applied against the ligaments holding up the back of the wrist. Depending on the size of the pet, certain household falls may create the kind of conditions necessary for just this sort of injury to occur. A cat could fall from a tree and therefore may be much better off kept indoors. Also, cats should not be allowed near an open upstairs window. These simple limitations on activity can help reduce the likelihood of this type of injury occurring to your pet.