I've had a stiff right knee for two years, and it pops/cracks when I bend it. Am I getting osteoarthritis?

I'm 18 and a freshman in college. I'm highly active (trail running and rock climbing) but didn't really get active until I was about 16. Before that, I had a very sedentary lifestyle, and until the past 18 months haven't really even been very athletic. When I started working on my physical fitness at 16, I finally noticed my knee. The popping is very audible, and I can feel what seem to be ligaments sliding over the front of my knee cap. I have never had a knee injury, so I'm assuming the cause is either genetics or my lack of exercise in the past. I also doubt I caused it by overtraining, as I noticed it fairly early on, and I stick to high intensity bodyweight exercises, no weights/heavy loads.
It never troubles me trail running, and rarely when climbing. However, jumping, squats, burpees, and similar exercises really make it noticeable.
I'm getting an x-ray in a few weeks, but would like to know ahead of time what to expect from the doctor. Should I be expecting to be diagnosed with arthritis? Does anyone have any positive experience with collagen/glucosamine/chondroitin? I'd like to think that knee-strengthening exercises would help prevent further damage, but I fear they could also do more harm than good. Please help, I'd like to know if I will be able to jump when I'm 25.

Also, I am fairly flexible. I took up yoga in August, and do at least 45 minutes of extensive stretching and meditating every day now.

I am a 20 yr old sophomore in college. This past summer I had knee x-rays and MRIs for both knees. I have been complaining of stiffness and pops/crackles for years. It started when I was about 13 or so. I have always had an active lifestyle with soccer, basketball, and golf. When I went to the doctors as a child I was told it is just growing pains blah blah blah. This past summer though when I went they said I mainly need strength training in the right areas. I am extremely inflexible. I worked on my calf, hamstring, and quad muscles for flexibility. Another part of my leg I strengthened was my hip-flexer. It made a tremendous improvement on my knees within 2-3 weeks. I attended physical therapy during this but you don't really need that. Just talk to somebody in the gym about how to strengthen or stretch those areas.

I would have pain after every round of golf. I played 4 times in 5 days last week. Guess what--- no pain.

You might want to ice your knees after long runs by the way for 15 minutes. I do this now after basketball.

It could also just be cartilage moving around when you bend your knee. Thats what happens to my knee after i got kicked in a soccer game. You never know with knee injuries.

You need to see a doctor. You may need stretching exercises, but it may be the bone rubbing.

hmm both of my knees pop and crack when i bend them and im only 16
its been happening since i was about 12..and iv never had any serious accidents.
Id really like to know aswell!

It's worn out, see your doctor !

I read a similar question in Runner's World magizine a long time ago, and the physician who answered it said if it doesn't hurt don't worry about it. I was interested because I had the same problem. But now more than a decade later it has developed into arthritis and is a problem. But then, I 'm more than thirty years older than you. But anyway, that was the doctors answer to the same question then. Maybe you can look it up in their archive.

If it was arthritis you would know because it hurts, swells, gets stiff, hot, etc... and different pressure systems (weather) make it worse. The snap crackle and pop can be normal, some get it some don't. I have crackled for years, even my 12 year old daughter snaps, crackles and pops as does my 26 year old son. The popping noise is typically a tendon (much like a rubber band pops when stretched too far). G&C (glucosamine and chondroitin) won't hurt you and can help keep your joints strong and lubed. Stay active, sedetary lifestyle will catch up to you later, much later, in life.