Thanks for writing to us.
The decrease in the muscle strength in the left leg is not likely to be due to spread of polio
after so many years. You need to consult a neurologist
to find out any neural deficit in the leg.
I hope this information has been both informative and helpful for you. You can consult me again directly through my profile URL http://bit.ly/Dr-Praveen-Tayal
Dr. Praveen Tayal