Anterior Cruciate Ligament (ACL) Injury


Your anterior cruciate ligament (ACL) is located in the middle of the knee joint, connecting the shin bone (tibia) to the thigh bone (femur). It crosses over diagonally with the posterior cruciate ligament (PCL) to control the backward and forward movement of the knee at the joint. It is one of four strong stabilising ligaments of the knee, along with the PCL and the medial and lateral collateral ligaments. The ACL works to stop the tibia from sliding forwards in front of the femur.  

What causes an ACL injury?

Injury to the ACL is a common knee injury, and often occurs alongside injury to other knee structures, such as the cartilage and the collateral ligaments. The different levels of severity of injury include a ligament sprain, a partial tear, or a complete rupture. ACL injuries are often sustained by athletes involved in high-impact sports that involve sudden changes in direction, such as basketball or soccer. ACL injuries are more common in females, which may be attributed to by muscle strength, control and conditioning.  Typically, ACL injuries are caused by:
  • Direct trauma/impact such as from tackles
  • Quickly changing direction
  • Sudden stops, especially during fast-paced activity
  • Improper landing from jumps
  • Overextending the knee

What are the symptoms?

Depending on the severity of your injury, symptoms may include:
  • Feeling unstable, like your knee is giving out from under you
  • A ‘popping’ sound on impact/injury
  • Pain and tenderness in the knee, especially on walking
  • Swelling
  • Limited movement in the joint

How are ACL injuries treated?

When the injury first occurs, it’s important to stop physical activity and avoid walking on the affected knee where possible. Following the PRICE principles (protection, rest, ice, compression and elevation) can help reduce the initial pain and swelling. If you have had a rupture or significant tear to your ACL, you may require surgery. It’s important that you have a diagnosis to confirm the extent of your injury, which may involve having an ultrasound, x-ray or MRI imaging. Your podiatrist can help you gradually rebuild the strength in your knee and surrounding muscles, and improve the range of motion in the joint, which will likely be restricted following your injury. Your podiatrist will make recommendations based on the cause of your injury to both help your recovery and reduce the risk of re-injury in the future. This may look at the use of orthotics to control motion at the feet and legs, assessing the stability of your footwear, teaching you how to strap your knee or recommending a brace, and physical therapy.