My Mom Has Had 3 Surgeries On Her Shattered Elbow.all

my mom has had 3 surgeries on her shattered elbow.all 3 times,the hospital has charged medicare about $16,000 per surgery.i want to know if its just some bone adjustments on her elbow,are they allowed to keep charging this cost to medicare.seems insane.and yes my moms care is paid for.just asking.