Swimming in the sea / so long as it is fairly pure / is healthier and less likely to lead to infection than a swimming pool. You may be advised to have salt baths ..... sea ... salt ..... check with your Doctor to be absolutely sure.
One small point about your flight to Corfu ..... after the anaesthetic your system will be a bit fragile, so rotate your feet and clench the muscles in your legs during the flight, as often as you can. Rotating the feet helps the ankles and keeps the circulation going.It is easy to do on a plane, and really does help.
Best of luck.