ACL tear

What is an ACL tear?

Your knee joint has a band of tissue in it called the anterior cruciate ligament, also known as the ACL. The ACL helps connect your thigh bone to your shin bone.

ACL tears are most common in athletes who play sports that involve sudden stops and starts, such as soccer, tennis, and basketball.

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ACL tear symptoms

If you tear your ACL, you may hear a ripping or popping sound when it happens. This is followed by symptoms that can include:

  • Pain or swelling
  • Difficulty standing on the leg with the injured ACL
  • Loss of some of the normal motion of your knee joint

ACL tear causes and risk factors

The biggest risk for an ACL tear is participating in sports that require quick stops and starts. Causes include:

  • Pivoting or changing direction while running
  • Slowing down or stopping suddenly
  • Landing awkwardly after a jump
  • Banging your knee against the ground or against another person

Depending on the activity, women are about three times more likely than men to tear an ACL. One reason for this is that the fibrous bundles that make up the ACL are smaller in women.

ACL tear treatment options

Nonsurgical options

If your ACL is not completely torn, your doctor may suggest changes in your lifestyle, such as:

  • An exercise program to strengthen the knee
  • Avoiding high-risk activities that could cause you to reinjure yourself
  • Wearing a knee brace during sports or other activities

There is a high risk of other damage to the knee (meniscus tears, cartilage lesions) with ACL tears treated non-operatively in young active patients so surgery is typically discussed.

Surgical options

A completely torn ACL will not heal on its own. It requires reconstruction surgery. A successful ACL reconstruction surgery will allow active athletes to return to their pre-injury form.

ACL reconstruction surgery usually requires a graft of your own tissue or tissue from a cadaver. Synthetic materials have been tried, but they don’t work as well as human tissue.

Surgery will also require you to do a rehabilitation program of up to six months.

Last reviewed: 
October 2019

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