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Anterior Cruciate Ligament Injury

Anterior Cruciate Ligament Injury

Definition

An anterior cruciate ligament (ACL) injury is a tear in a ligament of the knee. The ACL is a tough band of fiber in the middle of the knee joint. It connects the lower leg bone to the thigh bone. The ACL keeps the knee stable during movement by keeping the lower leg bone from sliding too far forward. An injury to this ligament can make the knee unstable. The injury may be partly torn or a complete tear.

Anterior Cruciate Ligament Injury
ACL injury
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Causes

ACL injury is caused be excess force on the knee. It occurs most often when your knee gets twisted or during a hard landing from a jump. It can also happen with:

  • Sudden stops or changes in direction
  • Sidestepping or pivoting
  • Direct contact

Risk Factors

Factors that increase your chance of ACL injury include:

  • Weak knee structure
  • Muscle strength imbalance between the quadriceps and hamstrings
  • Playing sports that require sudden changes of direction and deceleration
  • Use of incorrect technique for cutting, planting, pivoting, or jumping
  • Previous injury or reconstructive ACL surgery

Symptoms

Symptoms may include:

  • A popping sound at the time of the injury
  • Pain and swelling in the knee
  • Loss of full range of motion
  • Weakness or instability in the knee
  • Difficulty walking

Diagnosis

You will be asked about your symptoms and how you injured your knee. A physical exam will be done and your doctor will test your knee’s strength and stability.

The doctor may do further tests to see if there is any other damage to the joint. This may be done with:

  • X-ray
  • MRI scan
  • Arthroscopy

Ligament sprains are graded according to their severity:

  • Grade 1—Mild ligament damage.
  • Grade 2—Partial tearing of the ligament.
  • Grade 3—Complete tearing of the ligament.

Treatment

Talk with your doctor about the best treatment plan for you. Recovery time will depend on the severity of the injury. Immediate care includes:

  • Rest—Avoiding activities that cause pain.
  • Ice—Regular icing in first few days may help slow swelling.
  • Compression—Compression bandages can provide gentle pressure to help move fluids out of the area.
  • Elevation—Keeping the knee elevated at rest can help fluids drain out of the area.

Prevention

To reduce your chance of injuring the ACL:

  • Try plyometrics, a form of exercise that uses explosive movements.
  • When jumping and landing or turning and pivoting, your hips and knees should be bent, not straight.
  • Strengthen and stretch the muscles of your legs.
  • Maintain proper technique when exercising or playing sports.
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