Okay, Senior Ladies..???

If anyone here has MEDICARE... do they pay for a knee replacement surgery? I walked out of the hospital last August cause I just felt it wasn't the right time for me.  (Divorcing and it was a stressed decision because I knew I'd be losing insurance.) ANYWAY... I think I really should go on and do it or I'll just never be able to do as well as I could with this program. Anybody know re: the Medicare?  I'll be going on it in September. THANKS