Where is the medial mensical root in the knee? What is the purpose of a j brace? Does popping of the knee joint mean that the meniscus is torn?

The Attachment. The meniscus is c-shaped. At each end is a firm attachment to the bone. That's the meniscus root. A j brace helps stabilize the patella (kneecap). A torn meniscus is one reason for the knee to pop.