My 2 yr old chihuahua has luxating patella in BOTH her kneecaps. She went through a few weeks of being lame and holding up one of her legs, so we took her to the vets and after x-rays they told me her kneecaps were popping out of place.They said that it is very common in her breed and some dogs quite happily live with it, or need the op later in life or never need the op at all. Now here is my dilemma- I have had a very nice person offer to help me with the costs of the op to get her sorted.The vets said that if it is effecting her day to day then I am better to get the op done as she is likely to get much worse in the future and especially as she is only 2!! The thing is, some days you wouldnt even know she has dodgy knees! she zooms round like a loon then  the odd day she wont put one of her legs down and yelps if you go near her back end. The vet told me about the possible complications of the op and that it was quite complicated as they have to pin the joint etc and she has very small joints. They said that she could get an infection in the bone which would be really bad. Also she will need to have one knee done at a time and so would need a month cage rest after each op. Meaning a total of 2 months strict rest. Sounds awful. She manages to get around ok at the moment but do I do the op whilst I have the offer of finacial help as that is unlikely to come round again! and because she is only two and lkely to get worse-I dont want to leave her until she can barely walk before doing anything about it, but what if I let her have the op and something goes wrong I am going to feel really awful. What do you think?? 

My dog had a big knee op at age 10 and he did get an infection which meant they had to open him up 4 weeks later and remove the metal plate and pins as the bacteria were 'sticking to the metal.'
He had sort of healed enough from the op, according to the vet, but personally I don't think he had because his leg was almost just as bad.

However not every dog gets an infection and I would say that as it will only get worse, it may be better to have one leg done whilst she is young enough to recover more quickly.
If that one makes an improvement then good, if not then you know not to have the other one done.
If you have the chance of it being paid for now but not later then there is your answer.

Being such a small dog at least you can have a small crate in the room to restrict her movement that will be necessary afterwards.
Get a waterproof thing though to put over the bandage because if it gets wet she will have to keep having it rebandaged. The vet should be able to sell, or hopefully give you one.

good luck

My vet has just given me a home made bandage protector for my dog's leg bandage.
It's made from a saline solution pouch with one end cut off and holes made for a bandage strap to hold it in place. Easy to slip on when she does outside and really thick durable plastic.