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What is Anatomic Double-bundle ACL Reconstruction?

Anatomic double-bundle anterior cruciate ligament reconstruction is a new surgical technique employed in ACL reconstruction.

ACL reconstruction is a surgical procedure to replace a torn or damaged ACL ligament in your knee with a new ACL tissue graft obtained most commonly from your own body (autograft) or in rare cases from a deceased donor (allograft).

The innovative anatomic double-bundle anterior cruciate ligament reconstruction aims to restore the two functional bundles of the ACL in an attempt to better replicate the native biomechanics of the injured knee and promote long-term knee health. Whereas traditional reconstruction techniques utilized a single bundle graft that was usually placed in a non-anatomic position, the newly developed anatomic double-bundle anterior cruciate ligament reconstruction focuses on anatomic reconstruction techniques with an emphasis on individualizing ACL surgery based on each patient’s native anatomical characteristics, such as insertion site size, notch size and shape to better reproduce the function of the normal ACL.

Anatomy of the ACL

The anterior cruciate ligament (ACL) is made of tough, fibrous tissue and is one of the four major ligaments of the knee that connects the femur (thighbone) to the tibia (shinbone) and helps stabilize your knee joint. The ligament itself is made of thousands of individual fibers, that together form the ACL. Some of these fibers are organized into distinct bundles. The normal ACL has two primary bundles of fibers, and each bundle is named based on its location. The longer anteromedial bundle is positioned in front of the shorter posterolateral bundle. When an athlete tears their ACL, the knee will tend to buckle when pivoting or suddenly changing direction. To restore stability to the knee, your doctor may recommend an ACL reconstruction.

Indications for Anatomic Double-Bundle ACL Reconstruction

An ACL tear or injury is the main indication for anatomic double-bundle ACL reconstruction surgery. An ACL injury is a sports-related injury that occurs when the knee is forcefully twisted or hyper-extended. An ACL tear usually occurs with an abrupt directional change with the foot fixed on the ground or when the deceleration force crosses the knee. Changing direction rapidly, stopping suddenly, slowing down suddenly while running, landing from a jump incorrectly, and direct contact or collision, such as a football tackle can also result in injury to the ACL.

Preparation for Anatomic Double-Bundle ACL Reconstruction

In general, preparation for anatomic double-bundle ACL reconstruction surgery will involve the following steps:

  • A review of your medical history and a physical examination are performed to check for any medical issues that need to be addressed prior to surgery.
  • Depending on your medical history, social history, and age, you may need to undergo tests such as blood work and imaging to help detect any abnormalities that could compromise the safety of the procedure.
  • You will be asked if you have allergies to medications, anesthesia, or latex.
  • You should inform your doctor of any medications or supplements you are taking or any conditions you have such as heart or lung disease.
  • You may be asked to stop taking certain medications, such as blood thinners, anti-inflammatories, aspirin, or other supplements for a week or two.
  • You should refrain from alcohol and tobacco at least a few days prior to surgery and several weeks after, as it can hinder the healing process.
  • You should not consume any solids or liquids at least 8 hours prior to surgery.
  • You should arrange for someone to drive you home after surgery.
  • A signed informed consent form will be obtained from you after the pros and cons of the surgery have been explained.

Procedure for Anatomic Double-Bundle ACL Reconstruction

Almost all ACL reconstruction surgeries are performed utilizing a single-bundle reconstruction. A single-bundle ACL reconstruction employs a tendon graft to replace the torn ACL. Unfortunately, ACL tears cannot be sewn together or repaired and graft must be utilized to reconstruct the ligament. When the ACL is reconstructed, the tendon graft is positioned at the site of the anteromedial bundle. Grafts are held in position by making a hole in the bone called a tunnel. One tunnel is made in the tibia and one in the femur. The graft is held in the bone with a fixation device, such as a screw.

Instead of placing just one larger graft, the anatomic double-bundle ACL reconstruction procedure utilizes two smaller grafts. Therefore, there are essentially two ligament reconstructions, one for each bundle. The double-bundle procedure necessitates two additional bone tunnels to house a second graft and one additional incision. The surgical procedure may take slightly longer, even though surgeons doing this procedure can routinely perform it in a similar way to a single bundle ACL reconstruction.

In general, anatomic double-bundle ACL reconstruction surgery is performed under general anesthesia in a minimally invasive arthroscopic technique and involves the following steps:

  • Your surgeon will make two to three small cuts, about 1/4-inch-long, around your knee.
  • An arthroscope is inserted into the knee joint through one of the incisions.
  • An arthroscope is a thin tubular instrument with a camera, light, and a magnifying lens attached at the end that is connected to an external monitor and enables your surgeon to view the inside of the knee joint.
  • Along with the arthroscope, a sterile solution is pumped into the joint to expand it, enabling your surgeon to have a clear view and space to work inside the joint.
  • Miniature surgical instruments are passed through the other incisions and the torn ACL is removed and the pathway for new tendon grafts is prepared. The most common tendon grafts used are the patellar tendon (tendon of the kneecap) or one of the hamstring tendons (tendons located at the back of the thigh). In some instances, the quadriceps tendon located above the kneecap is utilized.
  • Your surgeon makes an incision around the knee area and obtains a suitable tendon to prepare the new ACL tendon grafts.
  • Two holes each are drilled into the upper and lower leg bones (femur and tibia) where these bones come together at the knee joint. These holes form tunnels in your bone to accept the new tendon grafts.
  • The grafts are pulled through the predrilled holes in the femur and tibia and fixed into the bones with screws or suture anchors.
  • After confirming satisfactory reconstruction, the scope and the instruments are withdrawn, and the incisions are sutured and bandaged.

Postoperative Care and Instructions

In general, postoperative care instructions and recovery after anatomic double-bundle ACL reconstruction surgery will involve the following:

  • You will be transferred to the recovery area where your nurse will closely observe you for any allergic or anesthetic reactions and monitor your vital signs as you recover from the effects of anesthesia.
  • You may notice pain, swelling, and discomfort in the knee area. Pain and anti-inflammatory medications are provided as needed to address these.
  • You are advised to keep your leg elevated while resting to prevent swelling and pain.
  • You will be given assistive devices such as crutches with instructions on restricted weight-bearing for a specified period of time. You are encouraged to walk with assistance as frequently as possible to prevent blood clots.
  • Instructions on surgical site care and bathing will be provided to keep the wound clean and dry.
  • Refrain from strenuous activities for the first few months and lifting heavy weights for at least 6 months. A gradual increase in activities is recommended.
  • An individualized physical therapy protocol will be designed to help strengthen the knee muscles and optimize knee function.
  • You will be able to resume your normal daily activities in a couple of months, but with certain activity restrictions. Full recovery and return to sports usually take about 9 to 12 months.
  • You may return to your work in about 6 weeks if your job is not too physically demanding. Those with physically demanding jobs will require a longer recovery period.
  • A periodic follow-up appointment will be scheduled to monitor your progress.

Risks and Complications

Anatomic double-bundle ACL reconstruction surgery is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as the following:

  • Infection
  • Bleeding
  • Pain and weakness in the knee
  • Adverse reactions to anesthesia
  • Blood clot or deep vein thrombosis
  • Damage to adjacent soft tissue structures
  • Knee stiffness or decreased range of motion
  • Re-rupture of the graft
  • Non-healing of the ligament