Anterior Cruciate Ligament (ACL) Rupture

The anterior cruciate ligament (ACL) is one of the four major ligaments in the knee. These ligaments, along with the muscles around the knee provide joint stability. The ACL is found deep inside the knee joint and prevents the femur (thigh bone) from moving forward during weight-bearing as well as preventing rotation of the joint.

When injuring the ACL, it is common to have a “pop” or “snap” sound or sensation and to experience sudden, usually severe, pain. The swelling will increase within 1-2 hours after the injury and the knee will often feel unstable like it is “giving way”

All patients who rupture their ACL should attend for assessment as soon as possible, and always within the first 2-weeks following injury. In most circumstances, a trial of conservative management should be undertaken before surgery is considered. There are exceptions to this, and your Physiotherapist is the ideal person to discuss what treatment options are most suited to your condition. 

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Rupture or tear of the ACL is a relatively common injury, particularly in certain sports. Women are two to five times more likely to sustain an ACL injury than men. ACL injuries occur most often when an athlete is pivoting, decelerating suddenly or landing from a jump (particularly if the knee is hyperextended forcefully). This injury could also be caused by another player falling across the knee or indirect contact sporting incidents. Factors that may increase a person’s risk of an ACL injury include:

  • Participation in high-risk sports, such as netball, football, soccer, basketball, volleyball and skiing, involving sudden start-stop movements.
  • Previous ACL injury
  • Females more commonly than Males


Specific orthopaedic tests performed by your Physiotherapist place stress on the ligament and can detect a torn ligament. An MRI may also be used to determine if the ligament is torn, and also to determine whether any associated injuries are present.

ACL injuries can be graded on a severity scale:

  • Grade 1: Mild injury to the ligament- stability maintained.
  • Grade 2: Partial tear of the ligament- some degree of instability of the knee.
  • Grade 3: Complete tear or rupture of the ligament- the knee joint is unstable.

Your physiotherapist will assess the level of instability of the joint, and the likelihood of associated injury (for example cartilage injury) and advise on the best course of action. Should surgical opinion be recommended, all patients should be offered prehabilitation to recover knee movement and quadriceps strength before undergoing surgery.


Initially, treatment aims to reduce pain and inflammation associated with the injury. Treatment and management options include:

  • Rest- restriction of all activity with crutches to enable non-weight bearing walking.
  • Reduce inflammation through rest, ice, compression, elevation and physiotherapy. Anti-inflammatory medication as recommended by a doctor or pharmacist may also assist in the healing process.
  • Knee brace if required.
  • Physiotherapy to assist in reducing pain and swelling and for maintenance of knee range of movement and strength.

If surgery is not required, the next phase of treatment aims to restore movement, strength and proprioception (“balance”) to the knee.

Surgical reconstruction is a very common method used to repair a completely torn ACL. Surgery involves replacing the damaged ligament (often using part of a tendon from somewhere else in the body) and stabilising the knee. Following surgery, physiotherapy will assist in reducing pain and swelling whilst commencing and progressing the rehabilitation program as indicated.

A comprehensive rehabilitation program is essential to ensure optimal function is regained after recovery from the injury or surgery. 4 Life Physiotherapy works with numerous state-level sporting clubs and specialist orthopaedic surgeons and has an outstanding reputation for excellent management of ACL injuries. 

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