I am 52 , wt. approx. 211 lbs. I have Psoriactic arthritis and Sjogrens, I take Enbrel and Methotrexate. Last Oct. I went to the store for groceries. I squatted down to pick up a can, and as I did I my leg gave way. It felt like a muscle was pulled behind my L knee. My knee did not hit the floor. Though It was difficult, I managed to stack some cans to push myself back to a standing position .When I got home I took some advil, and elevated my leg while I rested with ice and heat alternate (it appeared a bit swollen). I did not have a lot of pain though. I went to see my Rheumatologist 2 wk. later for my reg, appt. I told her about what had happen. She did an ultrasound because she thought there was some fluid accumulated at the back ok the knee . The ultrasound did not reveal any fluid. Since I did not have any pain and no fluid was evident, we decided to take a wait and see approach. A few weeks later I started to feel the pulling sensation again while walking up stairs, and it also felt like something was crawling around in the back of my knee. It came and went a few times. A few days later I did start to have pain with a burning sensation, so I started to wear compressions socks that I had kept from a surgery I had 1.5 years earlier. The added presser did seem to offer some comfort (especially at night, when I was trying to sleep). My doctor sent me in for a MRI of the L knee. I was dx. with a torn meniscus. I was also dx. with a torn meniscus of my R knee approx.. 6 mos. earlier, but did not have an issue with pull muscle felling at back of my knee. Several weeks pass and the pulling sensation came and went. On my next visit to my doctor she did another sonogram. She did not find any fluid, but did give me a steroid injection. The injection helped with the pain, but 3 weeks later I am once again having the pulling sensation in the back of my knee, and it feels like something is crawling around in the back of my knees again. This time I do have some pain as well. I have not done any thing other that my normal routine activities. Do you have any Idea what might be causing my problem, and what test would reflect what is happening to the area at the back of my L knee? I did see a specialist (orthopedic) after I was dx. with the torn meniscus of my R knee. He just gave some recommendations about what to avoid, no stairs (can not avoid) and no bike riding... Since the 2nd MRI showed the same dx, I did not go back to see him. Thank you.