ACL Surgery

2. How is an ACL Reconstruction done?

ACL reconstruction remove the damaged ACL and replace it with a graft in the former ACL site. Different graft choices are offered to reconstruct the damaged ligament. Dr. Yau will discuss the option of using native tissue from the patient (autograft) or processed cadaver tissue from a donor (allograft). Autograft choices include the hamstring or patellar tendon grafts. After thorough consultation with Dr. Yau regarding the advantages and disadvantages of each, the appropriate graft will be determined prior to surgery.

Once the graft has been obtained either through an autograft or allograft, a small incision is made in the front of the knee to place the arthroscope (a thin tube with a fiber-optic camera and surgical tools). The arthroscope allows the surgeon to see inside the knee during the procedure. After removing the torn ACL, Dr. Yau will clean the area. Next, he will drill small holes into the tibia and femur so that new ACL can be attached. The attaching devices are screws or a suspensory device. Once the new ligament is attached, the surgeon will test the knee’s range of motion and tension to be sure the graft is securely in place. The opening will then be stitched, and the wound, dressed. The knee is also stabilized with a brace. Typically, the patient goes home the day of surgery.

3. When is ACL Reconstruction Surgery Necessary?

It is estimated approximately 70% of ACL injuries occur from a traumatic event not involving direct contact. A doctor may use the Lachman’s test as one determinant of having ACL reconstruction surgery. While the patient lies flat, the doctor will bend the knee just slightly, at 15- to 20-degree angle. Next, the doctor stabilizes the thigh and pulls the shin forward. Between the shifting of the shin bone and the feel of the endpoint of movement, the doctor will learn how damaged the ACL is. Damaged ACLs may show more movement and less firm endpoint (the ligament may feel less solid or “soft”).

Doctors grade the results of the Lachman’s test on two criteria:

• The endpoint. If the endpoint is firm, that’s a sign that the ACL is limiting the amount of movement in the knee joint and is doing its job. A soft endpoint means that the ACL, and other secondary stabilizers, are not doing the job of limiting movement.
• The amount of laxity (or movement) of the joint. That’s based on a comparison of the injured knee to the noninjured knee.

These measurements will help determine if surgery is recommended.

In addition to a clinical exam, Dr. Yau will recommend diagnostic imaging such as an MRI or X-ray to help determine if the ACL has been torn.

4. When Should the ACL be Repaired?

ACL repair is a treatment for a complete ligament tear that results in instability of the knee. An ACL tear can be determined through physical exam and/or diagnostic imaging. A torn knee ligament may prevent a person from doing normal activities that involve turning or twisting the knee. The knee may also buckle or “give way”. Patients who do not address repairing the ACL surgically, risk injuring other structures in the knee.

5. How long does an ACL repair last?

Success of ACL repair surgery depends on various factors. Dr. Yau performs ACL surgery arthroscopically (using a scope that allows the doctor to see inside the joints). He will replace the damaged native ACL with an autograft or allograft to ensure optimal outcomes. The surgical technique and the patient’s dedication to the rehabilitation program will help determine the success of the repair. Generally speaking, return to sports following ACL surgery is between 6 to 12 months after surgery.

6. How long is the recovery after ACL surgery?

The recovery from ACL surgery varies depending on the patient, and is also influenced by the type of activities the patent wants to pursue. Rehabilitation plans also vary depending on the type of graft used in reconstruction surgery and any associated injuries (such as a tear to the meniscus). The surgery is often “out patient,” with the person discharged the same day.

Following ACL surgery, patients will be placed in a brace and encouraged to use crutches for 2 weeks to help protect the reconstructed ligament and facilitate healing. A physical therapy program aimed at returning range of motion and muscle function will be initiated immediately after surgery. Patients are instructed to follow all rehabilitation guidelines prescribed by Dr. Yau to help ensure an efficient and successful outcome following primary ACL reconstruction.  Recovery timeline varies between patients based on injury severity, age and concomitant injuries. Generally speaking, return to sports is between 6 to 12 months after surgery.

7. When can I run after ACL surgery?

Following surgery, patients will be encouraged to use crutches for the first 2 weeks to help promote healing. Physical therapy will be prescribed and will focus on returning range of motion and muscle function. Patients are instructed to follow all rehabilitation guidelines prescribed by Dr. Yau to help ensure successful outcome following ACL surgery. Recovery timeline varies between patients based on injury severity, age and concomitant injuries. Typically, return to full athletic activity will be between 6 to 12 months after surgery.

8. ACL Reconstruction vs ACL Repair, Which is Better?

Reconstruction and repair are used in very different situations. ACL reconstructive surgery is performed to repair a torn ACL and to regain stability and movement in the knee. ACL repair surgery is usually only performed when there is an avulsion fracture, which means the ligament and a piece of the bone has separated from the rest of the bone. The surgery’s goal is to reattach the bone fragment to the bone.

In the case of a complete tear of the ACL, Dr. Yau will recommend an ACL reconstruction which involves replacing the injured ACL with a graft in the former ACL site. The graft is typically attached to the bone with special screws or suspensory device. Various graft choices are offered to reconstruct the damaged ligament. Dr. Yau will discuss the advantages and disadvantages of each graft choice with the patient and the appropriate graft will be decided on before surgery.

9. ACL Reconstruction vs conservative treatment

The level of severity of an ACL injury will help determine between ACL reconstruction surgery and conservative treatment. In mild ACL injury cases, patients can do well with rehabilitation or physiotherapy. These patients may experience instability (the sensation that the knee “gives way” or buckles), but can manage those symptoms by modifying their activity level. Patients who do not have surgery risk the development of arthritis or damage to other structures in the knee.

In cases of a completely torn ACL, Dr. Yau will recommend ACL reconstruction surgery. For patients who want to return to full activity level, surgery will be encouraged to ensure stability to the knee.

10. ACL Reconstruction: Which is better, a Patellar Tendon or a Hamstring?

When the ACL is surgically reconstructed, a graft of tissue is used to make a new ligament. That graft comes from different sources. If the tissue comes from the patient’s own body, the two common options are the patellar tendon and the hamstring tendon.

• Patellar tendon: The advantages of a graft from the patellar tendon (the structure on the front of the knee that connects the kneecap to the tibia, or shin bone) is that it most closely resembles the ACL. The length is roughly the same as the ACL, which means the bone ends of the graft can be placed into the bone where the ACL attaches, allowing for the desired “bone to bone” healing. The disadvantage to this kind of graft is the risk of post-surgery patellar fracture or a tear of the patellar tendon. Most commonly, the side effect in the patient is pain in the front of the knee.
• Hamstring tendon: In ACL surgery, two of the tendons of these muscles on the back of the thigh are removed and “bundled” together to form a new ligament. Unlike with the patellar tendon and the pain that can result in the front of the knee, the hamstring tendon is believed to result in much less pain. On the down side, it takes longer for a hamstring graft to become “rigid” and fixation can be affected by post-operative motion. In this situation, a brace is often used to immobilize the knee for a week or two after surgery.

11. What causes ACL Reconstruction Failure?

What happens when ACL surgery goes wrong or when ACL surgery fails?

There are several causes of failure related to reconstruction of the ACL.

• Precise placement of the tunnels drilled for the placement of the graft is crucial. A slight variation of the tunnels drilled for the graft can create abnormal stresses and lengthen the graft. This can result in excessive laxity (looseness) and decreased range of motion.
• The failure of “fixation”: The fixation choice depends on the type of graft used. The fixation needs to secure the graft tissue in place, while the graft then becomes part of the bone tissue.
• Graft impingement: Caused by placement, the graft can be compromised, increasing the graft’s length and creating more wear, and ultimately, failure. The patient will experience decreased range of motion.
• Intrinsic graft failure: This can come from impingement or trauma. Immunologic reaction to an allograft (from cadaver tissue) can also weaken the graft and cause failure.
• Anthrofibrosis: This is the formation of scar tissue after both the injury and surgery that can lead to decreased range of motion.
• Trauma, which can cause excessive impact on the graft before it has fully healed. Significant trauma to the graft after it has healed can also cause failure.