Welcome to HCM!
I have gone em through your question and it reflects that from past two years you have pins and needle like sensation up your thigh, but no abnormality comes in MRI or x Ray of the part.
From my clinical experince I can say that you try to get an MRI and xRay of the 
spinal cord, thoracic and lumbar region. Usually, the pins and needle sensation point towards some neurological cause and needs investigation like MRI. now, from your question it looks like you have this problem on both sides , so it is likely that there is something compressing the nerves from above.  getting an MRI knee would not give any findings.
So, please donot worry, get the above investigations done. Meet a 
neurologist on person, he may like to do some tests like, sensation testing in that area of your body , and get 
nerve conduction study.
 You have not mentioned but if someone is suffering from 
diabetes or 
high blood pressure, one can have such complaints.
 Hope the reply helps you
 feel free to ask more queries.
Dr. Manisha Gopal.