i agree with skmcbride
it sound like you have a patella femoral tracking issue, though this isnt always an arthritic condition,
do a search on a lady called Kate Grace,, she is based in San Diago and probably the world expert in this condition,, she has developed a brace (neoprene) which works very very well.
wearing this and doing the recomemnded excercises works wonders,
i see people who have had surgical proceedures for this condition,,,, most seem un successful , ofcourse i probably dont get to see the successful ones.
but id say the last thing u want is surgury for this condition.
if ur struggling to get Kates contact details let me know and ill sort them out for u