Thank you for sharing your story, Lamees!
Looking at your response to the trauma in 2016 (feeling angry all the time, frantic and agitated), where do you place it on the Autonomic Ladder? You obviously found your way up to "ventral vagal" by mindfulness and by therapy supporting you on the way.
Regarding the knee problem we do look for self-devaluation when the tissue is/was weakened. Especially we focus on what the significance of the knee is in the context of your trauma and sensitization - was the conflict about a lack of movement and flexibility, did you experience yourself as too rigid or too weak? What would the leg and knee like to have done in the situation but couldn't? 

The typical "old brain" stress response is "more of that", meaning increase of function and possibly tissue. Like in conflicts of not feeling able to break down and process something, the body might attempt to help by increasing production of digestive juices, which in the long run will lead to digestive troubles and a change of the microbiome in the gut etc. 
Then, because of being sensitized for things to do with the conflict (your survival theme) and not being able to permanently resolve it, this in turn can lead to self-devaluation which is related to the "new brain" and has a weakening effect, which may reflect in the gut microbiome but also in other tissues like in muscles and bones!. This is how a mix of old brain/new brain themes comes about.

During the training, we'll go into much more detail with detailed hints by our symptoms, as to what shapes the "soil" and roots of our specific patterns.