Anterior cruciate ligament injury



The anterior cruciate ligament (ACL) is found in the middle of the knee and is one of four important ligaments that maintain the stability of the joint. The function of this ligament is to limit the anterior movement of the tibia (shinbone) and maintain the alignment of the femoral and tibial condyles.

The anterior cruciate ligament is most commonly injured during sports-related activities. Injuries occur with the twisting forces experienced by skiers and footballers.


 Twisting of the knee leads to ACL injury


In acute injury

  1. 70% of patients hear or feel a pop at the time of injury.
  2. Almost all patients notice swelling of the knee that occur within 24 to 48 hours of the injury.
  3. Patient feels severe pain in the knee with difficulty standing, walking or bending the knee


With old injury :

  1. The symptoms are less severe and usually the patient complains from repeated knee instability and giving way (the knee suddenly and unexpectedly is unable to support the person, and the leg buckles, leading to stumbling or falling) when running or walking quickly or climbing stairs or coming off or other activities that require knee stability.
  2. Repeated swelling and weakness of the front thigh muscles may occur.
  3. With chronic ACL injury knee osteoarthritis may occur .



Diagnosis is made by clinical examination of the patient's knee and testing the stability of the knee. MRI of the knee is used to confirm the diagnosis and to exclude other injuries of the knee as meniscial injuries or joint ulcers.

MRI of torn ACL


Treatment :

In Acute injuries

Knee may be treated symptomatically followed by repeated evaluations over first 2 to 3 weeks following injury.

Symptomatic treatment include :

  1. Applying ice or cold packs for 10 to 20 minutes, 3 or more times a day. To relieve pain & decrease swelling
  2. Medical treatment as analgesics & anti-edematous drugs.
  3. Knee support and walking aids like crutches for the first few days after injury

The injury is then treated surgically or non-surgically according to: 
1-patient's age
2-severity of injury (partial or complete tear)
3-patient's activities
4- presence of other knee injuries

Surgical reconstruction is usually delayed at least 3 weeks after injury to allow decrease in swelling and increase in range of motion. The ACL is recunstructed using tendon graft.

Conservative treatment includes functional stabilization through rehabilitation, muscle strengthening, bracing and lifestyle modification.


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