ACL Tears

The anterior cruciate ligament (ACL) is one of the main stabilizing ligaments of the knee, running through the center of the joint to keep the shinbone from sliding forward and to control rotation. When it tears, the knee can feel unreliable during pivoting, cutting, and changes of direction. Most ACL tears happen without contact, during a sudden stop, plant-and-pivot, or awkward landing. A torn ACL does not heal back together on its own, but it can be treated, and most people do well with the right plan.

Common symptoms include:

• A pop felt inside the knee at the moment of injury
• The knee giving way, followed by rapid swelling within an hour or two
• A feeling that the knee is unstable or shifts with each step
• The knee buckling during twisting, pivoting, or stepping off a curb at an angle

A focused physical exam of the knee, comparing it with the uninjured side, points to a torn ACL. An MRI confirms the diagnosis and checks for meniscus, cartilage, and collateral ligament injuries, which often occur alongside an ACL tear.

Not everyone needs surgery. Lower-demand patients can often do well without reconstruction:

• Physical therapy to strengthen the quadriceps and hamstrings, the foundation of nonsurgical care
• A brace for comfort and some support during activity
• Activity changes, staying with straight-line activities and avoiding pivoting and cutting sports

Reconstruction is recommended for active patients who want to return to pivoting or cutting sports, for younger patients, and for those with associated injuries. The torn ligament cannot be stitched back together; it is replaced with a tendon graft, using either your own tissue or donor tissue. Ongoing instability is a real risk of leaving it untreated, since repeated giving-way can damage the meniscus and cartilage over time.

• ACL reconstructionKnee

For a fuller explanation, including anatomy, diagnosis, and the full range of treatment:

• Anterior Cruciate Ligament (ACL) Injuries — AAOS OrthoInfo