Oscar, fitted with titanium prosthetic paws by Noel FitzpatrickNeuro orthopaedic veterinary surgeon Noel Fitzpatrick has been having a busy old time: hot on the heels of his world-first procedure to implant a prosthetic hip and femur in an American Bulldog comes the news that he has now fitted a cat with titanium prosthetic paws in another world-first.

Oscar the cat was minding his own business, basking in the late summer sun, when a passing combine harvester chopped off his hind paws.

Unlucky.

However, Oscar's luck turned when his veterinary surgeon, Peter Howarth from St Saviour in Jersey, referred owners Kate and Mike Nolan to Fitzpatrick Referrals to investigate the possibility of giving Oscar a pair of prosthetic paws.

Kate said: "We had to do a lot of soul-searching and our main concern has always been whether this operation would be in Oscar's best interests and would give him a better quality of life". Having decided it would, the Nolans asked Noel to go ahead. And so he came to give the two-year-old cat a pair of new artificial feet in a single, three-hour surgical procedure - something he says has never been done before by any team anywhere in the world.

The revolutionary design of the feet uses custom-made implants to 'peg' the ankle to the foot and mimics the way in which deer antler bone grows through skin. These pegs, or ITAPs (intraosseous transcutaneous amputation prosthetics), were first developed by a team from University College London led by Professor Gordon Blunn,  Head of the Centre for Bio-Medical Engineering at UCL's Institute of Orthopaedics and Musculoskeletal Science. Working in partnership with UCL, Fitzpatrick has pioneered the use of these weight-bearing prosthetic implants.

During the operation, the veterinary surgical team had to insert the ITAPs by drilling into one of the ankle bones in each of the back legs - an extremely delicate feat,  which could have fractured the ankle joint before the procedure had even begun, and even more challenging because it had to be performed twice. These artificial implants which are attached to the bone at an amputation site are coated with hydroxyapatite, which encourages bone cells to grow onto the metal. The skin then grows over the special umbrella at the end of the ITAP to form a resilient seal against bacteria and potentially fatal infections. The ITAP itself protrudes through the bone and skin, allowing the custom-built artifical paws to be attached securely. Click here to see x-rays and other case photos in the VetSurgeon media gallery.

Noel FitzpatrickFollowing successful surgery in November last year, the focus of the veterinary team has turned to the slow process of rehabilitation and helping Oscar to learn to walk again - firstly using external scaffolding anchored to the tibia  to protect the new implants until the ITAPs integrated into the bone and the skin grew onto the ITAP.  Remarkably Oscar was trying to stand within a day of the operation and despite some problems with infection that had to be overcome, in less than four months Oscar could stand and bear weight equally on all four limbs. He has since been fitted with a series of prototype new paws to ensure the best possible long term fit.

What makes this procedure so complicated is that Oscar's feet were severed at the junction of the tarsus and metatarsus. Noel said: "The real revolution with Oscar is because we have put a piece of metal and a flange into which skin grows into an extremely tight bone, with very narrow tolerances in the region of nanometres, rather than millimetres.  We have then successfully managed to get the bone and skin to grow into the implant and we have developed an exoprosthesis that allows this implant to work as a see-saw on the bottom of an animal's limbs to give him effectively normal gait.  Oscar can now run and jump about as cats should do.

Noel Fitzpatrick and the team at Fitzpatrick Referrals are the focus of a new six part documentary series: The Bionic Vet to be broadcast on BBC 1 at 10.45 pm every Wednesday starting on 30 June 2010. The programmes will focus on the multi million pound state-of-the-art vet practice in Surrey as well as the ways in which Noel is pioneering revolutionary new surgical techniques.