Click Here to return to the Vets Advice search page.
A:West Highland Terrier with Patella Luxation PetPlanet Vets PPAdmin email@example.com
Sorry to hear about Cosworth's leg problems -it is typical that he injures a front leg just when you are trying to sort out his back legs ! You are right to leave everything until his front leg has
completely healed. Surgery on the patella should only be carried out if he definitely needs it, and then he needs his 3 other legs to be in good shape while he recovers. It is not an emergency surgery, so you do have time to work out with your vet what is the best long-term treatment plan. It is a little bit unusual that he was 4 before it became obvious - often younger animals have problems and it can cause clinical signs in puppies. That may be an indication that it is not too severe a luxation, or that he was coping with it up to now, but arthritis or degenerative joint disease is developing. This is the long term problem - the patella slipping on and off the knee eventually damages the joint and it becomes comfortable and arthritic. Many little dogs live with a mildly luxating patella all their lives and never need surgery - but the more severe ones will benefit a lot from stabilisation of the patella.
Now to give you a bit more information about the condition. Luxation of the patella normally occurs because of congenital (present at birth) defects in the shape of the knee joint. but it can also occur because of trauma. The patella can luxate to the outside or inside of the joint - it is much more common to have it go to the inside. We are not sure why it happens in some animals and not others, but it is problems with the shape of the hip and knee as they develop which result in the patella
being pulled to one side so that it occasionally pops off the groove it is meant to slide on. It is seen mostly in little dogs such as Cavaliers, Yorkies and Jack Russells, but can also occur in big dogs. Dogs are often brought to the vet because of it within their first year.
There are different grades of seriousness - some just have a shallower groove than normal and the patella will only occasionally slip off with difficulty.At the other end of the scale some dogs have no groove at all and the patella is out of place all the time. Cosworth sounds somewhere in the middle- your vet will be able to assess that.
There are different surgical techniques to improve the situation. In mild cases it may be possible to keep the patella in place
using only soft tissue surgery - tightening up the tissue on the outside of the joint to pull the patella in that direction. but if there is actual skeletal deformity of the joint, then this will not be enough and bone
surgery will be needed. The most commonly required surgery is to deepen the groove which the patella slides up and down in and so keep in it place. More severe cases need more drastic bone surgery. Many cases will have a combination of techniques performed. They normally do very well once they have recovered from the surgery. There is always a slight risk of the patella luxating again.
Good luck with Cosworth,
Maeve Moorcroft MVB MRCVS
It may also be worth using the chatgroup area to contact other owners with experience.