Prosthetic cat paw may help people move forward

The smallest kitten born two years ago to a feral mother beside the back steps of a Glendon, N.C., home came into this world with two good front legs and two deformed rear legs. Before being weaned by his mom (who was thought to be a “he” before having kittens), this tuxedo-colored kitten would propel himself around the concrete back steps with his good paws and drag his nonfunctional hind legs behind.

George’s adoptive parents, Al Simmons, the clinical lead pharmacist for First Health Moore Regional Hospital in Pinehurst, N.C., and his wife, Kathy Vincent, a coronary care unit nurse at the same hospital, brought the kitten inside their house and named him George Bailey after Jimmy Stewart’s character in the movie, “It’s A Wonderful Life.”

George was born with two bad legs but with an indomitable spirit.

“He was small, got knocked around, but fought back like there’s not a thing in the world wrong with him,” remarked Simmons with obvious pride in this furry fighter.

But there was something wrong with George and each trip to eat, drink, go potty or play was a torturous ballet. He had voluntary motor control of his rear legs but had never walked on them.

George’s caring owners wanted to, in a way, make him whole again by giving him the gift-of-grab: the ability to gain rear traction and walk. Whereas prosthetic limbs act as sleeves that fit over the outside of the stump and are secured by various means, keeping this type of prosthetic paw on a hyperkinetic kitty like George proved to be a daunting challenge. Al and Kathy tried moleskin, crutch tips, even the fingers out of Isotoner gloves to give George a leg of sorts. Nothing worked.

George’s Mom and Dad wanted to make his life easier, to give him more mobility than what they described as “his pirouette dance” so they turned to Dr. Denis Marcellin-Little, an assistant professor of orthopedic surgery, originally from France, but now at the North Carolina State University College of Veterinary Medicine, to do something he’d never attempted before: to attach a prosthetic paw to the cat’s actual leg bone so it would be anchored, not strapped on.

On March 22, in a groundbreaking two-hour procedure called osteointegration, Marcellin inserted a prosthesis designed by the North Carolina State College of Engineering into the stump of George’s right rear tibia, the major bone between our knee and ankle.

One end of the central titanium shaft (about the size of a small drinking straw) is anchored in the bone and the other end extends outside the stump. A short sleeve made of a special, porous, biocompatible metal called tantalum surrounds the shaft from the end of the bone to the skin margin. The bone and skin are being allowed to grow into this part of the prosthesis to complete the seal.

The external shaft has a coupling to which a prosthetic leg and the actual prosthetic paw – which looks like a rubber coated shoehorn and is made of spring steel – will be attached. No pun intended, the spring steel stores energy and will really give a bounce to George’s step once it’s attached.

A second prosthesis on the left rear leg is unnecessary as cats have proven to get along just fine on three legs. Plus, this leg is more severely deformed with the kneecap pointing backward.

While waiting for the internal prosthesis to gain enough strength to support the actual prosthetic paw, a temporary foot has been attached. Leave it to the French, it’s an upside down champagne cork with a rubber sleeve for traction.

Within five days of the surgery, George started to use the cork like a real leg and could use it to catch his balance.

“He went from Flipper to a wildcat who could zoom through the house chasing our other cat, Desi,” says Simmons proudly about George whose cork is covered by the thumb of a $2 garden glove for traction.

The beauty of this surgery, which NBC 17 in Raleigh, N.C., reports has only been performed on just 70 humans digits worldwide, is twofold.

First, the dynamics of the prosthesis allow the bone of the leg to remain dense and strong. Secondly, the prosthetic paw won’t come off.

Because a cat lives in the “real world” and can’t be expected to understand the complexities of living with a prosthetic limb, George’s success with this new technology gives us some information about its versatility.

Unlike humans who can take great pains to keep a sensitive area sterile, George plops his surgery site down in his Yesterday’s News litter while going potty.

Other than treating a minor skin infection where the titanium rod protrudes through the skin, George’s recovery has been uneventful and Marcellin and George’s owners expect to “pop the cork” and celebrate the placing of George’s actual prosthesis before the first of June.

A breakthrough in engineering and modeling, Marcellin says, “It’s not too far fetched to think this could apply to humans who lose a foot to diabetes.”

Or a child who has lost a limb to a land mine.

This one-of-a-kind surgery to give a cat a more normal life may prove to be helping people move toward their own recovery. We hope this George Bailey does have a “wonderful life” and look forward to hope that this kind of medical advancement can help others to live better lives as well.