I'm 53 yr old female . Fractured knee cap years ago no treatment -I was walking down the hall calmly and heard/ felt a loud pop/snap (which did not hurt)., I took one more step and my knee collapsed forward with SEVERE pain, I saw stars and almost passed out it hurt so bad. I had 15 episodes of the buckling knee sliding forward that day..Really painful, sharp pain. Swelling as big as a large grapefruit. Can bend and straighten with nearly no pain. Nearly no pain when resting. Only severe pain on buckling which pitches me forward and sideways and almost falling badly. I must avoid this buckling at all costs, I got myself a compression ace with metal in support, and a brace with moveable metals on sides and straps above and below knee. Had crutches. Helps prevent buckling. MRI: Effusion, loose body 8mm X 4mm in joint space he thinks is bone, cyst, and tri osteothritis, loss of cartilage near femoral cardial, on weightbearing side, ligaments intact (one a little thinned, ACL and PCL all intact, meniscus intact. (This is all from memory - all other structures grossly intact I think). MD says the "loose body" might not be loose at all, but doesn't know if it is or not so another few xrays in a week to see if it moved.. Gave me better knee brace the same type, using same ace under and a walker as I would fall with crutches (which I could not tolerate anyway). He wants me to walk. He has allowed me stand during my lectures but forbade my hospital work. He gave me lidocaine and cortisone into joint. He worried about my diabetes and cortisone. He said I may be better in a week. I may have physical therapy. THEN he said I may need total knee replacement if it does not work. Ultram and alleve. He wants me to walk. All of this sounds fine except this... I am terrified to walk, what if it buckles? I tear up just thinking it might again., I cannot tolerate the pain, I nearly pass out each time. Also, the Ultram will do nothing for the severe pain because it is so acute and the pain subsides in 3-6 minutes per episode anyway but he wants me to take it anyway.. Any advice? Is the loose body catching in the joint causing the pain? I trust him, I think he is good. He also wrote I had a strain/sprain, which I found on the Xray form. YIKES!