ankle pain and loss of stability

In 1969, I severed a nerve at the knee while playing football. This was only discovered through an exploratory surgery in 1970 and I was told that to reconnect the nerve was not possible and was left with foot drop and a brace. About 1973, I visited a physcian who later performed a then innovative surgery in which he detached the muscle that pulled the foot down and attached it on top of the foot.
I am now 54 years old and while this surgery was at that time a major improvement, my ankle stability has degrenerated substantially in the past 6-7 yrs. I am feeling quite a bit of pain while walking. I feel as though I am walking on the side of my foot and this is evident by the rapid wear on on the outside shoe sole. There is also much stiffness in the joint and I can freguently feel something cracking or popping. My orthopedist told me just to deal with the pain but walking is increasinly more difficult. Am I doomed to wear a hard brace or can surgery help? Soft braces seem to help little. Also, I weigh about 300lbs and I know losing weight would help and I am working on that. Thanks