ACL FAQ

Most Frequently Asked Questions

If you suffer from an injury to the anterior cruciate ligament in your knee, you may have questions about the ACL tear (and the surgery and rehabilitation you need).
Below we have listed the answers to some of the frequently asked questions about the ACL injury

What is the Anterior Cruciate Ligament (ACL)?

The ACL is one of four strong fibrous tissue bands called ligaments that hold together and support the knee. The ACL runs diagonally inside your knee between your thigh (femur) and shin (tibia) bones. Your ACL primarily keeps your knee stable when you turn, cut, twist and pivot. Unfortunately, it is the knee ligament most often injured. An ACL tear is one of the most common and devastating sports injuries.

What is an ACL injury?

The three grades of ACL injury range from mild to severe.
1. Sprain Trauma to the ligament is relatively minor. Some of the fibers are stretched.
2. Grade II – Partial Tear Trauma to the ligament is more severe. Some of the fibers are torn.
3. Grade III – Complete Tear This is the most severe ACL injury. The fibers of the ligament are
completely torn.

How do ACL tears happen?

Injuries to the ACL can occur in several ways, usually without contact. High speed twists, bending or extending the knee beyond its normal range, or landing “wrong” from a jump may result in an ACL tear. Basketball, volleyball, tennis and soccer players, as well as skiers and snowboarders are particularly vulnerable. More than 90 percent of the time, it tears completely.

What are ACL tear symptoms?

When your ACL tears:

  • Seventy percent of those suffering an ACL tear feel or hear a pop.
  • You’ll feel pain that increases when you bend your knee or try to walk. It may hurt to put any weight on that leg.
  • Usually your knee will swell quickly.
  • Your leg might feel unstable. This is because your shin can move forward beyond its natural range (called loss of anterior stability). Also swelling and pain in your quadriceps (front of thigh) may keep the muscle from working properly.
  • Your range of motion might be severely limited. It will be painful to straighten your leg.

How are ACL injuries diagnosed?

ACL tears can be confirmed only through medical evaluation or magnetic resonance imaging (MRI). If you experience symptoms of a torn ACL, you should get a medical professional’s diagnosis as soon as possible to begin your recovery. If your ACL is torn, you’ll be referred to an ACL professional specializing in knee injuries.

Why does recovery from ACL surgery take so long?

  • The knee is the largest joint in the body. It works in coordination with every other muscle and bone on that side of your lower body up through your back. The knee’s ability to support all activities, especially demanding sports, is astonishing. A knee injury is a big disruption to your body.
  • The ACL is critical to stabilizing your knee.
  • Very little blood circulates inside your knee, which slows healing.
  • ACL surgery rehabilitation develops functionality and strength. Functionality is being able to do something. Strength is being able to do it with force. Strength takes longer to regain than functionality.

Can I retear my reconstructed ACL?

Yes. Even the best reconstruction surgery cannot eliminate the possibility of a retear.

Are females more likely to tear an ACL?

Yes. Studies have shown females are two to seven times more likely to tear an ACL than males competing in the same sports. Theories for this difference between sexes range from hormonal and anatomical differences to lower biomechanic and neuromuscular control.

What is an ACL reconstruction?

An ACL reconstruction is a surgical procedure that involves removing the remains of the damaged ACL and replacing it with another form of soft tissue, called a graft. The graft is either autogenous, which comes from the patient, or an allograft, which is tissue donated by an individual at the time of death.

Is surgery always needed for an ACL tear?

Surgery is not required for all ACL injuries. Partial tears, in which a physical examination shows a relatively stable knee, may be treated with bracing and rehabilitation. Even some patients with complete ACL tears do not need reconstruction. These “copers” are typically older patients with lower physical activity, who do not participate in pivoting and cutting activities.

Why should the ACL be reconstructed?

One reason to reconstruct the ACL is to provide knee stability that allows for return to activities and sports. Another reason is to provide knee stability in order to prevent more injury, such as a meniscal tear, which may eventually lead to degenerative joint disease.

What happens if I don't have an ACL reconstruction?

The anterior cruciate ligament provides stability to the knee particularly with twisting, turning and change of direction activities.  Immediately after an ACL tear, your knee will be sore but the pain will settle provided there are no other injuries. The end result of the cruciate ligament tear is an unstable knee, not a painful knee. Most people with an anterior cruciate ligament tear are unable to return to competitive sporting activities without reconstruction. Straight line activities such as walking, swimming and cycling are still possible. Cruciate ligament reconstruction surgery is undertaken to restore stability to the knee joint to improve quality of life and allow sporting activities. It is also generally accepted that an unstable knee with a torn cruciate ligament is more likely to develop arthritis in the longer term. The risk of arthritis after an ACL tear is increased but that does not mean that it occurs in all patients.