The ACL stabilises the knee for slicing, twisting and leaping and pivoting action. The anterior cruciate ligament is in the middle of your knee joint. Any time you tear an ACL, you will normally sense or hear a pop, experience the knee change outside of place and produce important swelling 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