The patellar articular surface may get replaced but into a lesser extent dependant upon the findings of the surgeon in the course of the surgery, which has a patellar button which is also comprised of the identical material because the tibial insert. Broken bone and cartilage from your thighbone, shinbone https://www.theorthopaedicandpainpractice.com/what-should-i-do-if-i-have-a-collateral-ligament-injury-of-the-knee/?_gl=1*xbbxlb*_up*MQ..&gclid=Cj0KCQjwkt6aBhDKARIsAAyeLJ2krYJSOuy5mZksrNqH-VDjQwW1ScD49yD8BUWysDG6u6bJPCSbXVUaAuCPEALw_wcB