Two years ago I had a motorcycle crash where I broke my left hip and damaged my left knee.My hip rapaired itself nicely but the knee is still a problem. In March I underwent a knee Op. My ACL had considerable scarring around it and this was removed. My knee had damage to the back of the Knee cap and this was also removed. I now find myself with a very weak left leg. If I try to do any strengthening exercises it just gets painful and swells. I am desperate to get back to running as I used to,is there anything I can do to help this along ?