I WEAR ORTHOTICS AND THEY HELP MY KNEES I ALWAYS WORE THE SOFT TYPE ?

USUALLY BLUE AND THEY WORKED WELL FOR YEARS BUT I THINK OF LATE MY FEET HAVE FLATTENED FURTHER SO TIME TO RENEW BUT THE PODIATRIST WHO IS NEW GAVE ME CAD CAD NEW BALANCE THEY ARE CALLED WHICH ARE RIGID HAVE BEEN AGONY ON MY FEET ,IS THIS BECAUSE I NEED A NEW REFIT OR IS IT BECAUSE THEY ARE A DIFFERENT MATERIAL IE HARD AN D RIGID,R DO I NEED TO BREAK IN SLOWLY WHICH I NEVER DID I JUST WORE ALL THE TIME I SHOULD MENTION I HAVE A ARTHRITIC KNEE BUT MY OLD ORTHOTICS HANDLED MY KNEES O K THANKS FOR ANY ADVICE