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What Is ACL Reconstruction? 

A sprain or tear of the anterior cruciate ligament (ACL) is one of the most common knee injuries and is the one that most frequently requires surgery. The ACL connects the femur (thigh bone) to the tibia (shin bone) and provides stability for the knee joint structure. 

When the ACL tears completely, it is not typically possible to stitch it back together. Generally, an ACL reconstruction will be necessary to return to sport activity or for instability. 

Common Reasons for an ACL Reconstruction 

Partial tears to the ACL are rare; most are complete or nearly complete tears that require reconstruction. Injuries to the ACL are often non-contact injuries that happen when: 

  • Changing direction suddenly 

  • Landing poorly from a jump 

  • Stopping suddenly 

They can also happen from a direct blow, such as from a fall on the knee, a football tackle or a car accident. 

Candidates for ACL Reconstruction 

The ACL is necessary to stabilize the knee for jumping, twisting and changing directions. Injured athletes who want to return to play, especially basketball, baseball, football and soccer players, are often in need of ACL reconstruction. Women are more likely than men to have an ACL injury. 

Patients with a mildly stretched ligament—a grade 1 sprain—will usually not need surgery, but having a full tear (grade 3) when the ligament has detached from the bone, usually means surgery. Grade 2 sprains, where the ligament has stretched to the point of looseness or instability, are rare; the ligament usually tears completely rather than stretches. 

Preoperative Considerations 

The doctor will usually want to take a medical history and conduct a physical examination before determining if a patient is a candidate for ACL reconstruction. X-rays and magnetic resonance imaging (MRI) scans can help determine if an ACL injury requires the ligament to be reconstructed. 

The Procedure 

ACL reconstruction starts with a ligament graft. The surgeon replaces the torn ligament with other tissue. Often, this replacement comes from the patient’s own body (an autograft), such as from the patellar tendon in the knee, the hamstring tendon at the back of the thigh or the quadriceps tendon at the front of the thigh. Other times, the surgeon will use an ACL tendon from a cadaver donor, which is called an allograft. 

The surgery to insert the graft is done arthroscopically, with small incisions, small tools and a flexible camera attached to a video monitor. The aim of the surgery is for the body to build a new ligament over the graft. 


ACL reconstruction is usually a same-day surgery, no hospital stay necessary. Patients usually need a brace and will use crutches for one to four weeks. 

Physical therapy for four to six months is often necessary to strengthen the muscles around the knee and to return the knee to its full range of motion. Most people can resume working and playing some sports in four to six months after the surgery. Some sports that involve rapid changes of direction, such as soccer or basketball, may be require 9 to 12 months to return to play. 

If you have a knee injury and suspect you may need ACL reconstruction, follow the link below and answer a few short questions. Someone will get back to you as soon as possible. Thank you for choosing Summit Health. 

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