ok well i have been having knee problems for about 11 years now. i went to see the doctor when i was about 7 yrs old. they said the lump on the right side of my knee cap was the growing pains thing, but i'm 18 yrs old now and the lump has gotten bigger. my knee has been giving out on my when i run or walk. one incident was when i was running and my right knee gave out and i tried 2 catch myself with my left leg and my left knee gave out 2 so i fell to the floor the doctors put me on crutches for 2 weeks after that. i'm wondering if i should try and get a knee replacement...my knee does swell when i have been on it and it gets stiff when i've been walking or sitting down. the pain isn't 2 bad just bothers my a lot but i put up with it. can anyone give me an idea on what it could be? and if i should try and get a knee replacement??