### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
I was squatting down to pick up a pitcher of water and when i came back up to standing I felt an extreme tightening in my knee. It felt as if someone was squeezing my knee all around it , but especially in the back of my knee. It lasted about 2 minutes and I almost lost my balance. The rest of the day it was a bit gimpy but it bounced back. I had an x-ray that revealed no abnormal bone structure and no arthritis. This knee has bothered me off and on since this happened about 6 months ago. It varies from pretty sore under the knee cap to almost feels ok again. It also clicks to different degrees when I walk.

### output:

Hello, Since the x-ray turned out to be normal you need not have to worry much. Because there won't be any bony Injury.  Usually this symptoms might have caused due to either of the reasons. Ligament injury or the muscle weakness.  Since its bothering you from 6 months I think you should opt for an MRI.  Usually any ignored knee injury in later stages develops major issues, so it's better to the cautious.  Also, the pain you mentioned is behind the patella, I will advise you to do water fermentation and then static hamstring and static Qua Chat Doctor.  Which should help the knee muscles to have enough strength to avoid the knee cap bone to rub against the thigh-bone and thereby relieving the inflammation. Wait and see with the exercise if all goes well than MRI might not be needed. But it fails then we need to take an MRI for precise exercise prescription. Hope I have answered your query. Let me know if I can assist you further. Take care Jay In