The ACL stabilises the knee for cutting, twisting and leaping and pivoting action. The anterior cruciate ligament is in the center on the knee joint. When you tear an ACL, you may often feel or listen to a pop, sense the knee shift from spot and produce major swelling in 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