Anterior Cruciate Ligament (ACL) Tears

ValleyOrtho’s physicians treat a wide range of common knee injuries, including anterior cruciate ligament (ACL) injuries.


There are four main ligaments that stabilize the knee. The ACL is located in the center of the knee and is primarily responsible for stabilizing knee rotation that occurs during cutting and pivoting activities.

The ACL stabilizes the knee by:

  1. The ligament provides protection against excessive anterior and rotational movement of the knee through its connection to the lower leg bone (tibia) and thighbone (femur).
  2. The ACL provides sensory feedback to help with balance and proper knee positioning during activity.


ACL injuries are more common among athletes and are often caused when playing sports that include running, jumping and pivoting. Problems occur when:

  • Changing direction rapidly
  • Stopping suddenly
  • Slowing down while running
  • A bad landing from a jump
  • A direct collision, such as a tackle


In addition to pain and likely swelling, patients may report a “popping” sound when injured. Another common symptom is the feeling that the knee is “giving out.” Whereas some individuals are able to cope without an ACL, others will continue to experience knee instability and may suffer secondary damage to the knee


A thorough history and a physical examination of the knee is often the most reliable method of diagnosis. The knee experts at ValleyOrtho will assess the knee’s range of motion, swelling, muscle strength and laxity. A magnetic resonance imaging (MRI) scan may be ordered to visualize all the soft tissue in and around the knee and evaluate for other injuries.


The knee experts at ValleyOrtho examine conservative, nonsurgical treatments before proposing surgical intervention. The choices for treatment will be individualized and will take into account the age, activity level and the desire to return to activities which require significant amounts of cutting and pivoting or other high-speed movements.

  • One form of conservative treatment is to modify the patient’s sports participation. This could involve discontinuing sports involving cutting and pivoting, such as soccer and basketball. These sports could be replaced by sports that do not involve cutting and pivoting, such as swimming or running.
  • Another form of conservative treatment is rehabilitation with a physical therapist. Rehabilitation for an ACL injury focuses on improving the patient’s proprioception and muscular stabilization.
  • Surgical ACL reconstruction involves replacing the torn ACL with a graft. The new ACL graft can either come from the patient (autograft) or a cadaver (allograft).