Reviewed by DR. D. DATTA.
Ex. Emergency Medical Officer.
Ligament is a band of tough fibrous tissue that connects bones or cartilages. Like strong rope it holds the bones together in a joint, thereby making the joint stable and limits its movement.
Anterior cruciate ligament (ACL) is present in the knee joint.
Knee joint is formed at the site of meeting of three bones, the femur (thigh bone), the tibia (the shin bone) and the patella (kneecap, a small triangular bone in front of the knee joint).
There are four main ligaments in the knee joint.
1 Medial collateral ligament present on the inner side of the knee joint. It prevents inward bending of the knee joint.
2 Lateral collateral ligament is present on the outer side of the knee joint. It prevents outward bending of the knee joint.
3 Anterior cruciate ligament-Â It is present in the middle of the knee. Anteriorly and below it is attached with the top of the tibia. It passes upwards, backwards and laterally to be attached with the bottom of the femur. It prevents the shin bone from sliding out in front of the thigh bone.
4 Posterior cruciate ligament is stronger and shorter than the anterior cruciate ligament. Posterior cruciate ligament injury is less common than anterior cruciate ligament injury. Posteriorly and below it is attached with the top of the tibia. It passes upwards, forwards and medially to be attached with the bottom of the femur. It prevents the shin bone from sliding backward under the femur.
Anterior cruciate ligament injury is a common knee injury.
It may be associated with other knee injuries such as cartilage, meniscus or other ligament injury.
There may be partial or complete tear of anterior cruciate ligament. Usually tear is complete tear.
Causes of anterior cruciate ligament injury
An ACL injury can occur
1 If there is a sudden stop of movement.
2 sudden changing direction while running.
3 Incorrect landing from a jump.
4 Overextend your knee joint.
5 Violent hit from the side of the knee, such as during a football tackle.
ACL injury is more common in athletes involved in sports such as football, basketball, skiing.
It is more common in female athletes possibly due to differences in muscular strength, differences in anatomy of pelvis and lower extremity, effect of estrogen on ligaments.
Symptoms of anterior cruciate ligament injury
1 Most patients hear a loud pop at the time when tear occurs.
2 Severe knee pain, tenderness in knee joint.
3 Swelling of the knee joint usually occurs within 6 hours.
4 Loss of range of motion of knee joint.
5 Unstable knee.
Diagnosis of anterior cruciate ligament injury
Doctor will take proper history from the patient. Examine the knee joint for swelling, tenderness and range of movement.
Investigations done to confirm the diagnosis and determine the severity of injury.
X-ray – anterior cruciate ligament cannot be seen by x-rays but it can show any bony injury that may be associated with the anterior cruciate ligament injury.
Magnetic resonance imaging [MRI]- This is a non-invasive procedure. Anterior cruciate ligament injury and any other soft tissue injury can be seen by MRI.
Arthroscopy- It may be done for diagnosis and also for surgical management of anterior cruciate ligaments injury.
Treatment of anterior cruciate ligament injury
Immediately after injury
Rest- After injury stop all activities that may cause movement of the knee joint.
Application of ice- Wrap ice in a cloth and apply ice on the knee joint for maximum 20 minutes every two hours.
Compression- Wrap the knee joint with elastic bandage to prevent movement of the knee joint.
Elevation- keep a pillow under the knee joint to elevate it.
Instability due to ACL injury may cause other injury of knee joint such as injury to the menisci and cartilages. Ultimately this may lead to arthritis of knee joint.
Treatment options are non-surgical treatment and surgical treatment.
Treatment option in a particular case depends upon the age, how much the patient is active and severity of injury.
Non-surgical treatment is for those people who live a sedentary lifestyle, who are not sportsperson. Non-surgical procedure carries higher risk of re injury to the knee joint.
Non-surgical treatment includes bracing and physiotherapy.
Bracing- patient wears a brace around the knee that makes the knee joint more stable.
Physiotherapy under guidance of a physical therapist will strengthen other ligaments of the knee joint and increase its stability.
Surgical treatment is considered when.
1 The patient is active, a sportsperson.
2 When there is associated other knee injury along with ACL injury.
3 When there is considerable instability of the joint which may lead to other knee injury if not repaired surgically.
It is done under general or regional anesthesia by arthroscopic surgery.
The torn ACL is replaced by a tendon from the patient (autograft), or from a donor (allograft).
Quadriceps, patellar or hamstring tendon may be used for autograft.
Patellar, semitendinosus, gracilis or achilles tendon may be used for allograft.
Usually, a patient may return to his normal activity after one year.
