Failed ACL Repair

The anterior cruciate ligament (ACL) is one of the most critical stabilizers of the knee. When the ACL is torn, patients often experience instability, pain, and difficulty returning to sports or active lifestyles. While most ACL injuries are treated with reconstruction using a graft, certain cases—particularly when the ligament is torn near its attachment—may be suitable for ACL repair. This procedure attempts to preserve the patient’s native ligament by reattaching it to the bone with sutures or anchors. Although ACL repair has advanced with modern surgical techniques, there are situations where the repair does not succeed. This is referred to as a failed ACL repair.

What is a failed ACL repair?

A failed ACL repair occurs when the reattached ligament does not heal properly or loses its function, resulting in persistent instability, pain, or reduced knee performance. Unlike ACL reconstruction, where failure often involves problems with a graft, failure of a repair means the original ligament did not re-establish its strength and stability after being reattached. The repaired tissue may stretch out, scar tissue may interfere with healing, or the repair site may not hold due to biological or mechanical reasons.

Failure does not necessarily mean the ligament has torn again completely; instead, it may remain weak and unable to provide the stability patients need to return to their activities.

What are the symptoms of failed ACL repair?

The symptoms of a failed ACL repair often resemble those experienced at the time of the initial injury. Common warning signs include:

• A sensation that the knee is “giving way” or buckling during movement
• Recurrent swelling, particularly after exercise or sports
• Ongoing or worsening pain in the knee joint
• Stiffness or difficulty fully bending and straightening the knee
• Trouble resuming athletic activities or even daily tasks like climbing stairs or walking on uneven surfaces

Some patients also notice clicking, catching, or locking in the joint, which may signal associated injuries to the meniscus or cartilage that developed because of instability.

How is a failed ACL repair diagnosed?

Diagnosing a failed ACL repair requires a thorough evaluation by an orthopedic surgeon with expertise in sports medicine. The process typically begins with a detailed discussion of the patient’s surgical history, including how the ligament was repaired, the type of fixation used, and the recovery timeline.

A physical examination is then performed to assess knee strength, range of motion, and ligament stability. Specific tests such as the Lachman test or pivot shift test help evaluate whether the ligament is functioning as it should.

Imaging studies play an important role as well. X-rays provide information on bone anatomy and hardware position, while an MRI scan allows the surgeon to closely evaluate the repaired ligament and surrounding structures. If revision surgery is considered, advanced imaging may be used to carefully map the knee and plan the procedure.

What are the risks and contributing factors?

A number of factors can increase the likelihood of a failed ACL repair:

• Tear pattern and location: ACL repair is only suitable for certain types of tears, typically those close to the ligament’s bony attachment. If the tear pattern is not ideal, the ligament may not heal securely.
• Biological healing response: Not all ligaments heal at the same rate. Some patients may have limited blood supply to the injured area, reducing the chances of success.
• Technical factors: The method of fixation, surgical precision, and the ability to restore proper tension in the ligament all affect the long-term outcome.
• Re-injury: Returning to activity too quickly or experiencing another traumatic event can stress the repair before it fully heals.
• Rehabilitation issues: Inadequate physical therapy, or overly aggressive rehabilitation, can both contribute to failure.

When ACL repair fails, instability can place additional stress on the meniscus and cartilage. Over time, this increases the risk of further injury and can accelerate the development of knee arthritis.

Recognizing a failed ACL repair early is critical. Ongoing instability not only limits a person’s confidence in their knee but also leads to secondary damage in the joint. For athletes, this may mean missed seasons or shortened careers. For active adults, it may impact the ability to participate in fitness activities or even perform normal daily routines without fear of the knee buckling.

What happens when a failed ACL repair occurs?

When an ACL repair fails, the most common next step is revision surgery. In most cases, this involves converting the repair into an ACL reconstruction, where a tendon graft is used to replace the ligament. Revision procedures are more complex than the original repair and require careful planning to ensure tunnels, fixation points, and any additional injuries are addressed properly.

Some patients may also need additional procedures such as meniscus repair or cartilage restoration at the time of revision. Rehabilitation after revision surgery is a key part of recovery, and it is typically slower and more cautious compared to the timeline following a primary repair.

For patients with lower activity demands, non-surgical management may be an option. This can include bracing, physical therapy, and activity modification. However, for younger and more active patients, ongoing instability is rarely sustainable without surgical correction.

If you have undergone ACL repair surgery and are still experiencing pain, swelling, or instability in your knee, these may be signs of a failed ACL repair. Addressing the issue early can help protect your knee from further damage and restore your ability to move confidently.

Dr. Brian Waterman, Board Certified and Fellowship Trained Orthopedic Surgeon and Sports Medicine Expert in Winston-Salem, North Carolina, has extensive experience evaluating and treating complex knee injuries, including failed ACL repairs. With advanced training in revision procedures, Dr. Waterman develops personalized treatment plans to restore stability, function, and quality of life.

Do not let persistent knee problems keep you from the activities you enjoy. Contact Dr. Brian Waterman’s office today to schedule a consultation and learn about your options for recovery.