Tinker had a lot of pain when it first started. We medicated for a couple of days and then she was fine. Once you learn where to check and how to pop it back over when it slips, that helps quite a lot as does a good joint supplement.
These days Tink is mostly just fine as long as she gets her Joint Strong and her black currant seed oil, which she needs for her neck/back issues as well. The expense of the surgery and the stress of keeping her quiet for weeks makes me unenthused about surgery. Tink is very active...a big pogo sticker and loves chasing around the yard, so the knee thing does not seem to be slowing her down.