There are typically three levels of ACL injuries.u003cbr/u003eu003cstrongu003eFirst Degree:u003c/strongu003e Here, the ACL ligament is stretched without any tear in the fibers. This may cause slight tenderness and swelling. However, the knee does not give out during activities.u003cbr/u003eu003cstrongu003eSecond Degree:u003c/strongu003e Here, the ACL ligament is partially torn and can cause moderate swelling and tenderness. The knee feels unstable and thus, would require a doctor’s treatment immediately.u003cbr/u003eu003cstrongu003eThird Degree:u003c/strongu003e Here, the ACL ligament is completely torn, and it causes extreme swelling and pain. The knee feels unstable and gives out while walking. A doctor has the best solution in such cases as it may also call for surgery depending on its severity.u003cbr/u003eA knee brace can be an excellent solution for some individuals who need ACL protection. However, knee surgery is usually meant for restoring knee joint stability and preventing the additional risks of developing knee arthritis in the future. After an ACL surgery, physical rehabilitation is essential.