via BBC News
Robo-cat Missy may have used up most of her nine lives but now she is
back on the prowl after becoming the world's first feline to have an
artificial knee replacement.
Vets found her close to death after she was run over by a car, but she
completed a miraculous recovery after undergoing pioneering new surgery
to rebuild her limbs and fit a specially-made metal joint.
The eight-year-old family pet had lain injured in a bush for two days
with one hind leg broken in eight places and the other with a completely
It was only because of her owners' relentless efforts that they found
'I heard a tiny little cry coming from the bush and I knew she was calling
me,' said owner Louise Morris, of Petworth, West Sussex.
Dr Noel Fitzpatrick, the vet who performed the operation at his clinic
in Guildford, said: 'It was a case of putting Missy to sleep forever
or developing an artificial knee, which had never been done before.
'Amputation was not an option since the other hind leg was broken in
The skin and tendons at the back of one foot had died due to crushing
of the blood supply and the tissue had all fallen off, leaving raw bone
In order to re-grow tissue and cover the bone, a collagen mesh made out
of pig's bladder was used.
The various broken bones were then placed in a scaffolding of pins called
a Spider (Secured Pin Intramedullary Dorsal Epoxy Resin Frame) until
the bone and tissue healed.
The new total knee replacement implant for the other leg was designed
by Dr Fitzpatrick, Professor Gordon Blunn and Mr Jay Meswania of OrthoFitz
It is made of two parts which are linked together with a hinged mechanism
so that the knee ligaments - which had all been shredded - would no longer
be required and the knee could no longer dislocate.
Uniquely, the implant was custom-designed based on a CT scan of Missy's
knee and exactly fitted Missy's measurements, both in terms of the size
of her bones and the range of motion of her knee joint.The three-inch
long implant is made out of stainless steel and is bonded to the thigh
bone and the shin bone using cement.
Dr Fitzpatrick said: 'The most difficult thing about the operation was
miniaturising the implants and matching the hinge motion to allow walking,
running and jumping, which cats do a lot of.
'A human patient with a knee replacement would probably walk and maybe
even run but would rarely expect to jump.'
The operation took two-and-a-half hours to cut out the old damaged knee
and replace it with the new joint.
After twelve agonising weeks of treatment her owners were over the moon
to take Missy home to pamper her and treat her to her favourite chicken
Ms Morris now faces a huge vet's bill but said: 'Missy is a valuable
member of the family and we would do whatever possible provided she has
a good quality of life.'
She added: 'Noel is a genius. He makes it possible for animals to have
the same level of care as humans.'
(Missy's new knee)