What is an ACL Repair?

The anterior cruciate ligament (ACL) is an important stabilizing ligament in the knee that is frequently injured in sports. It is estimated that there are between 100,000 and 200,000 ACL tears annually in the United States. When surgical treatment is indicated, ACL tears have historically been treated with a complete reconstruction of the torn ligament using either an autograft or allograft tendon. As technological advancements in sports medicine have progressed, there are now ways of repairing and saving one’s native ACL that may have torn. An ACL repair may yield a better outcome compared to an ACL reconstruction given that one’s native ACL anatomy is preserved.

In the last decade newer arthroscopic techniques, smaller and stronger implants and suture materials, and advanced surgical skills have helped make ACL repairs a viable treatment option for some patients. During ACL repair, small non-metallic suture anchors and high strength suture are used to repair the native ACL back to its attachment site on the bottom end of the femur where it commonly tears away from. ACL doctor Richard Cunningham, MD has utilized ACL repair in certain types of ACL tears for 10 years, and has seen great patient outcomes.

ACL Repair vs Reconstruction

Although ACL reconstruction surgery has been the gold standard of treatment for ACL tears, certain types of ACL tears can be repaired, thus preserving one’s normal anatomy. If an ACL tears in the middle of the ligament, these injuries still require ACL reconstruction surgery and currently cannot be repaired with any high degree of success. However, in some ACL tears, the ligament fibers pull away from their attachment on the femur. These particular types of tears can be repaired and a more invasive reconstruction can be avoided.

With ACL reconstruction, the entire torn ACL is removed from the knee. Bone tunnels are drilled in the femur and the tibia and a tendon graft (usually taken from the patient and less commonly from a donor as donor tendons retear more easily) is then anchored into these bone tunnels. Although ACL reconstruction surgery leads to very good outcomes in the majority of cases, around 15% of ACL reconstruction surgeries fail with retearing of the ACL graft. Dr. Cunningham has performed thousands of arthroscopic ACL reconstruction surgeries, but most ACL reconstruction surgeries are done by surgeons who do less than 20 ACL reconstruction surgeries a year. If the surgery is not performed properly, one’s graft can more easily retear and there can be other damage to the knee such as meniscus tearing which can lead to early arthritis in the knee joint. In addition, a redo or revision ACL reconstruction surgery has an even lower success rate, and the recovery time is typically one year to return to all activities.

Whenever possible, it is best to try to preserve your ACL and have it repaired. ACL repair can be done if the ligament tears up at the top of the ACL. One of the biggest benefits of ACL repairs is the elimination of the graft harvesting process. By not having a piece of tendon removed from around your knee and instead repairing the native ACL, patients have a quicker recovery compared to reconstruction surgery. Other ACL repair benefits compared to ACL reconstruction include:

  • Conservation of blood vessels and nerves to the ACL
  • No tunnel drilling or removal of bone from the femur and tibia
  • Preservation of the exact attachment sites of your ACL to the tibia and ACL
  • Restoration of the exact sized ACL you had
  • Marked decrease in muscle atrophy compared to reconstruction surgery
  • Full return to sports in half the time it would take following ACL reconstruction

Why Save the ACL?

The biggest advantages of repairing one’s ACL is preserving the normal anatomy and biomechanics of the knee. By preserving the anatomy and biomechanics of the knee, one is able to more fully restore normal knee range of motion, stability, strength, and function Additional benefits to repairing a torn ACL include:

  • Overall, less pain and a quicker recovery
  • In younger patients where the growth plate is still present, a repair does not necessitate drilling across the growth plate which could result in a limb length discrepancy or angular growth deformity of the femur or tibia.
  • No pain from a graft harvest
  • If the repair does fail, there is still the option to do a reconstruction

How is an ACL Repair Performed?

During this minimally invasive procedure, ACL doctor Richard Cunningham, MD creates several small incisions around the knee. The torn ACL is freed up from any scar tissue. Strong sutures are woven through the torn ACL fibers. These sutures are loaded onto small, strong, non-metallic suture anchors which are placed into the native ACL attachment site on the end of the femur thus anchoring the torn ligament back in place. To provide additional support to the healing ligament, an “internal brace” is also used. With this, a strong braided suture is placed along the repaired ACL, and this suture is secured in one anchor in the femur and then into another anchor in the tibia, thus supporting the ACL while it heals. This functions as an internal support built around the injury, allowing for earlier return of motion, while providing enhanced protection and an opportunity for the original ACL to heal tightly in place so it is not stretched during the healing process.

Typically, an ACL repair is performed in an outpatient setting. No hospital stay is required. The procedure flow is generally:

  • Patient intake and prep including a femoral nerve block to help decrease postop pain as well as a light general anesthetic in surgery
  • The leg is position in a special leg holder and the knee is prepped
  • An arthroscope and other specialized fine instruments are introduced into the knee joint through small incisions
  • The torn or ruptured portion of the ligament is mobilized from any scar tissue
  • Strong, non-absorbable sutures are woven through the torn ACL
  • These sutures are loaded onto sutures anchors which are placed in the femur bone thus reattaching the torn ACL to its native attachment site.
  • An internal brace suture is placed alongside the ACL to help support the ACL during healing so that it is not stretched.

The surgical incisions are closed. Sterile dressings are applied as well as a knee brace. Patients are released from the outpatient surgery center a few hours after surgery.

What is Recovery Like After an ACL Repair?

Recovery from an ACL repair begins immediately. Patients are allowed to put weight on the knee right away, as long as a hinged knee brace is on the leg with the brace holding the knee straight. When not walking, the knee brace may be removed and immediate knee range of motion is encouraged. Patients are instructed to ice and elevate the knee regularly during the first week. Formal physical therapy can be started the day after surgery. Pain medications are prescribed and usually only needed for the first week. Although the rehabilitation course is similar to an ACL reconstruction, everything moves along faster as there is less pain and swelling as the surgery is less invasive. The patient and doctor will work together to determine when one can return to normal activities, but this usually occurs twice as fast as after ACL reconstruction surgery.