Anterior cruciate ligament (ACL) surgery involves placing screws and staples to hold the knee in place. These screws may cause pain in the knee. In some cases, ACL surgery can fail.

The ACL works to stabilize the joint. It is crucial in stopping forward movements of the shin bone and limiting knee rotation.

Learn more about knee anatomy.

ACL injuries are common in athletes, particularly those who play football, basketball, and handball. In some cases, people with ACL injuries may require surgery.

ACL surgery involves reconstructing the ligament. Surgeons use screws to attach the reconstructed ligament to the femur (thigh bone) and the tibia (shin bone).

A person may experience pain after surgery due to the placement of these screws. Pain may also be a sign of ACL surgery failure.

In this article, we look at the symptoms associated with ACL screw pain and surgery failure, causes, complications of ACL surgery, treatment, and when to contact a doctor.

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During ACL surgery, a surgeon replaces a person’s anterior cruciate ligament. As it is a major surgery, all people should expect to feel the following:

  • bruising
  • swelling
  • redness

These will occur around the knee joint. Because the fluid in the knee may leak down the shin, bruising, swelling, and redness may also occur in the front of the shin and ankle.

According to one 2018 review, approximately 75–97% of all ACL surgeries have a positive outcome.

However, in some cases, the ACL screws may fail. Doctors sometimes refer to this as graft failure. Often, this requires additional surgery.

Symptoms of knee graft failure or ACL screw pain may include:

  • knee pain that worsens with activity
  • pain behind the kneecap
  • pain when crouching or kneeling
  • a feeling of looseness in the knee
  • limping
  • stiffness
  • swelling
  • feeling unstable

ACL screw pain may be due to the placement of the screws. For example, if they are too close to the joint, this may cause pain or stiffness. It is also possible for the screw edge to rub on a tendon, resulting in pain.

Additionally, ACL surgery can fail and cause pain.

The most common causes of ACL failure are:

  • trauma to the knee
  • misplacement of the tunnel
  • lack of graft incorporation

Surgical error

According to one 2016 analysis, errors associated with surgical technique is the most common cause of relapse instability following ACL reconstruction. The authors write that this accounts for 77–95% of all ACL failure cases.

Some of these possible surgical errors include:

  • incorrect positioning of the tunnel for the ACL graft
  • incorrect fixture of the graft at the shin or thigh bones
  • incorrect placement of the graft resulting in it catching in the notch in the lower end of the thigh bone
  • incorrect placement of screws, leading to them rubbing against tendons or being too close to joints


If a person reinjures the ligament, the ACL replacement may begin to fail.

Although the replacement ligament is strong, injury is still possible. Additionally, if a surgeon uses metal screws, these can dislodge or move due to impact.

A 2021 review examining whether wearing a knee brace when returning to sports after ACL surgery was effective found mixed results. However, the authors note that several studies suggest bracing is effective in preventing additional injuries.

Aggressive rehabilitation

ACL failure may occur in people who are too enthusiastic or aggressive during rehabilitation therapy. If a person tries to rush their recovery, this could result in loosening the new graft or dislodging the screws.

Learn more about what to expect during knee surgery rehabilitation.

Screw type

A surgeon can choose between two types of screws for ACL surgery: metal and bioabsorbable.

Metal screws can sometimes interfere with MRI scans and can be difficult to remove if further surgery is necessary.

Therefore, some surgeons may opt for bioabsorbable screws. However, a 2016 review of studies found that using bioabsorbable screws may increase the risk of surgical failure as they may break during the procedure. There is also an increased risk of infection and inflammation with this type of screw.


People who undergo ACL surgery may receive a donor graft. This procedure can also involve the use of a person’s own tissue.

For those needing a donor, there is a possibility of the body rejecting this new tissue.

All surgical procedures carry risks of complications.

Some possible risks of ACL surgery include the following:

Some rarer complications of ACL surgery include:

  • rupture or movement of the graft
  • fractures in the tibia or femur
  • infections due to bacteria or mycosis
  • injuries relating to the blood vessels
  • nerve injuries

To diagnose ACL surgery failure, doctors will conduct physical examinations and scans. These scans include X-rays, CT, or MRI scans. However, metal screws may interfere with MRI scans.

Learn more about the difference between a CT and an MRI scan.

The likely treatment for ACL failure is revision surgery.

Sometimes, a person may need an osteotomy, which involves cutting the bone to realign the graft.

A doctor may also prescribe pain medication to help a person manage pain until the surgery. A person can also take over-the-counter (OTC) pain relievers to help reduce pain and inflammation.

Heat and ice therapy may also be beneficial in relieving any inflammation and pain.

People should contact a doctor if they experience pain and weakness after their rehabilitation therapy following ACL surgery.

Additionally, they should consult a healthcare professional if they injure the area again.

ACL screw pain is very similar to ACL surgery failure. A person may experience pain, weakness, stiffness, looseness, and instability.

This may result from surgeon error, reinjury, aggressive rehabilitation, the type of screw used, or donor tissue rejection.

In the case of surgical failure, a person may need to have revision surgery.