ACL injury

ACL injury is a common knee injury that occurs when the anterior cruciate ligament (ACL) is torn. The ACL is one of four ligaments that connect the shinbone (tibia) to the thighbone (femur) and helps to stabilize the knee joint.
ACL injuries are most often caused by sudden changes in direction, landing awkwardly from a jump, or being hit directly on the knee. Contact sports such as basketball, soccer, and football are the most common causes of ACL injuries.
Symptoms of an ACL injury include:

Pain and swelling in the knee
Instability or giving way of the knee
Difficulty walking or running

ACL injuries can be diagnosed with a physical exam and MRI. Treatment for ACL injuries typically involves surgery to repair or reconstruct the ACL. Following surgery, physical therapy is necessary to regain range of motion and strength in the knee.
ACL injuries can be serious, but with proper treatment, most people can recover and return to their previous level of activity.