Putting the pep back in pet's step
By Sarah Netherton/University of Illinois College of Veterinary Medicine
Total hip replacement — replacing the ball and socket of the hip joint with prosthetics — was performed on 332,000 people in the United States in 2010, according to the Centers for Disease Control and Prevention.
Pets, too, can benefit from this procedure, which will soon be offered again at the University of Illinois Veterinary Teaching Hospital in Urbana.
"Conditions in animals that can be treated with this surgery include arthritis, hip dysplasia (where the joint is malformed) or traumatic injury or fracture of the head of the femur, the leg bone that attaches to the joint," said Tisha Harper, a veterinarian who is board-certified in small animal surgery.
Harper has completed training and is now certified to perform the surgery. She uses what is known as a "press-fit" system for hip replacement. The press-fit system depends on an initial tight fit and then bony in-growth, over the long term, to provide stability to the joint.
The press-fit system is a cementless system.
"Cemented implants can also be used," she said, "but the press-fit approach eliminates complications associated with the use of bone cement such as thermal damage to the bone. The head of the femur and socket, called the acetabulum, fit together to hold the implants in place."
The choice of cemented versus cementless implants is often based on the shape of the animal's bones and how secure the implant is during surgery.
This procedure can be performed on both cats and dogs, though Harper said it is mainly done for dogs.
"In the past, veterinary surgeons were able to perform total hip replacement surgery only on medium-sized and large dogs," she said. "Today, a micro-hip system is available for small dogs and cats, although I most commonly see dogs."
To determine if an animal is a good candidate for a total hip replacement, the first step is to take X-rays.
The animal's growth plates must be closed for it to be eligible for the surgery. Breeds mature at different rates, but in general, the surgery can be performed as early as 12 to 14 months of age.
"The goal of a total hip replacement is to provide a pet with a pain-free, functional and biomechanically sound hip," Harper said. "Patients generally tend to do well following this procedure."
The total time of hospitalization, including the surgery, is two to three days. Patients should be totally recovered in about three months.
Harper recommends taking X-rays three months after the surgical procedure to check on the implants, and again once a year for a year or two after the surgery. Improvement is usually immediate.
"Even though there may be some discomfort after surgery, the patient generally starts using the limb within a few days," Harper said.
Post-operative care includes restricting the pet from running and jumping anywhere and from walking on slippery floors.
Harper said the main complications of this surgery are dislocation of the hip prosthesis and infection. Because of this, she advises owners to walk their newly recovering pets with a leash and sling to prevent any splaying of the legs, which can cause dislocation of the hip.
Pain medications and basic physical therapy also are part of post-operative process.
Even if the pet needs both hips replaced, the procedure would be done one hip at a time to allow for the animal to properly recover from the surgeries.
"Since they are quadrupeds, animals are able to shift their weight, and therefore, some pets can do well with only one hip being replaced," Harper said.
For more information about a total hip replacement, speak with a veterinarian familiar with this specialized procedure.
An archive of pet columns from the University of Illinois College of Veterinary Medicine is available at http://vetmed.illinois.edu/petcolumns/. Requests for reprints of this article may be directed to Chris Beuoy, firstname.lastname@example.org.