How long and how do you heal knee bone contusions? I have bruising on the patella, and the end of the femur. From an injury I suffered 2 yrs ago.

Usually 6-8 weeks. You are way outside the window for calling it due to a bone bruise--should be seen by an orthopedist for history, exam & likely new x-rays to see what is going on. It may be trying to tell you something.
Let me explain. You had two after the contusions of the bone and still have symptoms, this means to me that permanent damage to the bone in that area, i go and check it out with orthopedic surgeon.