I have elephantiasis in my legs, have sever pain in both knees, and unable to walk any distance. I am a 52 year old male, otherwise in good shape with no heart problems, low cholesterol , no diabetes, etc., just being 335lbs because of the lymphedema . My Orthopedic doctors tell me I am not a candidate for knee replacement . Is there a specific reason I would not be able to have full knee replacement surgery?