It all depends on the severity of the luxation.
Ginger has both knees that luxate and she doesnt need surgery, but both Tequila and Kylie did.
I think as long as it isnt effecting them (isnt painful, isnt chaning their gate, etc) then they wont do surgery, but if your chi is painful, if your chi is walking funny (hopping, putting more weight on the other legs, etc) then they might see it necessary to do surgery.
Also the grade of the luxation is a factor. There are 4 grades.
Grade 1 is a very mild case and never needs surgery...the knee cap slides out but not very often and it pops back in right away
Grade 2 usually doesnt end up in surgery either...the knee cap can slide out of the grove a little easier and might take a second or two to pop back in, but always pops in on its own
Grade 3 the patella pops out quite often and usually needs assistance in popping back in. This is where you can see a change in your dogs walk. Tequila and Kylie would bunny hop to get their knee cap back in the grove...they would also stretch their leg all the way back to try to pop it in. Sometimes we have to help and guide the kneecap back in...but I wouldnt do that unless a doc shows u how
Grade 4 is when the knee cap pops out and cannot be put back in without assistance from us. The knee cap is almost always out and is very hard to put back in.
THe most common reasons for luxating patella is a shallow grove in the knee where the kneecap sits.....the knee should be shaped like two hills, with the knee cap sitting at the bottom between the two hills...if the grove isnt deep, the kneecap can slide out. In the case with toy breeds, usually they have little to no grove in their knee and that is why they have such problems with their knees.
Another reason but less common in toy breeds is the ligaments and muscles surrounding the kneecap...it could be that one muscle is pulling too tightly to one side forcing the knee cap our or visa versa...the muscle isnt tight enough and the knee cap can easily slide in and out.
A vet is the only one who can tell you for sure whats going on. I dont ever remember a clicking sound from my dogs, but that isnt to say it cant happen.
Make an appointment and let us know what the vet says...try not to worry because more often then not your chi wont need surgery.