i have the same problem with my legs..way too skinny compared to the rest of my body.
they have implants to augment the calf area and u could go for fat graft on the ankles
thats what my doc suggested but there is the problem of fat resorption ,not to mention unpredictability of fat grafts.....so cant really say that would be a permanent solution and im sure u re aware of the risks associated with implants
I've never heard of anything for this problem other than a lot of exercise specifically for the calves - running being one of the best. Gyms always have equipment designed to work that area too.