MY WIFE HAD REPLACED HER LEFT KNEE,ABOUT 5 YEARS AGO,IT DID NOT GO WELL!FIRST,SHE HAD A STROCK(?)--RESULT: LOST SIGHT IN LEFT EYE: HAS TO USE A WALKER ( I HAVE TO DO EVERY THING AROUND THE HOUSE,NOW HER RIGHT KNEE IS ALSO IN BAD SHAPE:MY QUESTION--CAN REPLACEMENT KNEE BE CORRECTED?--IS THE KNEES CONTROL IN THE BACK--?IF THIS FAILS,WILL SHE NEED A WHEEL CHAIR.( HER AGE IS 84--)