My min foxy had the same problem of limping and after a while she was fine. Took her to vet a week ago and they diagnosed luxating patella as well and about $1600 to put a pin in her knew to prevent it slipping out again. A luxating patelling involves the knee slipping out of the joint and somehow the dog manages to get it back into the joint themselves which is why they only limp for a short time.
IF they do not get the surgery then with wear and tear the joint wears down to a point where they cannot slip it back into place and they end up in massive pain leading to leg amputation. It is true that they end up with arthritis with or without the surgery but the arthritis is much worse WITHOUT the surgery
