An ACL tear cannot heal on its own. However, not all ACL tears require surgery. Whether or not the ACL needs treatment primarily depends on your activity level. The ACL is most important for cutting and pivoting sports, such as tennis, basketball, and skiing. Those with strenuous jobs involving heavy lifting and climbing also usually need a functioning ACL. So for those who desire unrestrained activities or are unable or unwilling to modify their activity level, ACL surgery is encouraged.
People who lead a more sedentary lifestyle may get by with exercise and sometimes a brace to stabilize the knee. However, some may experience giving way with simple activities such as going down stairs or stepping off a curb. In these cases, your surgeon will often recommend surgery to restore normal activities and prevent further damage to the knee.