ACL Reconstruction and Surgery

An anterior cruciate ligament tear is one of the most common knee injuries. Athletes who participate in high demand sports like soccer, football, basketball and skiing are more likely to injure their anterior cruciate ligament.

If you have injured your anterior cruciate ligament, you may require ACL surgery to regain full function of your knee. This will depend on several factors, such as the severity of your injury and your activity level.

Anatomy

Three bones meet to form your knee joint: your thighbone (femur), shinbone (tibia), and kneecap (patella). Bones are connected to other bones by ligaments. There are four primary ligaments in your knee. They act like strong ropes to hold the bones together and keep your knee stable.

Collateral ligaments are found on the sides of your knee. The medial collateral ligament (MCL) is on the inside and the lateral collateral ligament (LCL) is on the outside. They control the sideways motion of your knee and brace it against unusual movement.

Cruciate Ligaments are found inside your knee joint. They cross each other to form an "X" with the anterior cruciate ligament (ACL) in front and the posterior cruciate ligament (PCL) in back. The cruciate ligaments control the back and forth motion of your knee. The anterior cruciate ligament runs diagonally in the middle of the knee. It prevents the tibia from sliding out in front of the femur, as well as provides rotational stability to the knee.

The weight-bearing surface of the knee is covered by a layer of articular cartilage. On either side of the joint, between the cartilage surfaces of the femur and tibia, are the medial meniscus and lateral meniscus. The menisci act as shock absorbers and work with the cartilage to reduce the stresses between the tibia and the femur.

Description
It is unusual for ACL tears to be isolated injuries. About half of all injuries to the anterior cruciate ligament occur along with damage to other structures in the knee, such as articular cartilage, meniscus, or other ligaments.

Cause
The anterior cruciate ligament can be injured in several ways:

• Changing direction rapidly
• Stopping suddenly
• Slowing down while running
• Landing from a jump incorrectly
• Direct contact or collision, such as a football tackle

The mechanism of injury is often associated with deceleration coupled with cutting, pivoting or sidestepping maneuvers, and awkward landings. It is estimated that 70 percent of ACL injuries occur through non-contact mechanisms while 30 percent result from direct contact with another player or object.

Symptoms
When you injure your anterior cruciate ligament, you might hear a "popping" noise and you may feel your knee give out from under you. Within 24 hours, your knee will swell. If ignored, the swelling and pain may resolve on its own. However, if you attempt to return to sports, your knee will probably be unstable and you risk causing further damage to the cushioning cartilage (meniscus) of your knee. After a complete ACL tear, some patients are unable to participate in cutting or pivoting-type sports, while others have instability during even normal activities, such as walking.

Other symptoms of ACL tear:

• Pain and swelling after activity
• Feeling of instability or laxity in the knee
• Discomfort while walking
• Tenderness along the joint line
• Loss of full range of motion
  

Partial tears of the anterior cruciate ligament are rare; most ACL injuries are complete or near complete tears. About half of ACL injuries occur in combination with damage to the meniscus, articular cartilage or other ligaments. Secondary damage may occur in patients who have repeated episodes of instability due to ACL injury. With chronic instability, the risk of further meniscus tears and cartilage damage is increased.

Imaging Tests
Although Xrays may not show any injury to your anterior cruciate ligament, X-rays can show whether the injury is associated with a fracture. Also it is important for your orthopedic surgeon to appreciate the orientation of your anatomy and examine for any deformity that may predispose to ACL tear.

MRI allows for better images of soft tissues like the anterior cruciate ligament. MRI is also useful to evaluate for other related injuries such as to the cartilage or meniscus.

Nonsurgical Treatment
A torn ACL will not heal without ACL surgery, but nonsurgical treatment may be effective for patients who are elderly or have a very low activity level. If the overall stability of the knee is intact, Dr. Samimi may recommend simple, nonsurgical options such as a brace and physical therapy.

Surgical Treatment
Young athletes involved in agility sports will most likely require ACL surgery to safely return to sports. The goal of ACL reconstruction surgery is to prevent instability and restore the function of the torn ligament, creating a stable knee.

What happens during the procedure?
ACL tears cannot be sutured (stitched) back together. To surgically repair the ACL and restore knee stability, the ligament must be reconstructed. Los Angeles orthopedic surgeon Dr. Samimi specializes in ACL reconstruction using the most up to date minimally invasive techniques.

First, Dr. Samimi uses arthroscopy to examine your entire knee. The arthroscope is inserted into your knee through a small incision large enough to fit the small camera. The arthroscope is connected to a video monitor in the operating room. All the tissues of your knee joint -- the cartilage, meniscus, and ligaments are inspected.

Once a thorough understanding of the problem is obtained, the torn ACL tissues are removed by the ACL surgeon. To do this, small surgical instruments such as scissors, graspers, and motorized shavers are inserted into the knee joint through these same small incisions. Next, bone tunnels are drilled into the thigh bone (femur) and shin bone (tibia) where a newly prepared graft is attached using screws. This newly prepared graft acts as a scaffold for a new ligament to grow on and will eventually provide the stability and support necessary to return to sport. Usually 2 to 3 small incisions are all that are needed in knee arthroscopic ACL reconstruction. The benefits of less invasive techniques include less pain from ACL surgery, less time spent in the hospital, and quicker recovery times. The procedure usually lasts 1 to 2 hours depending on the findings and the treatment necessary.

At the end of the ACL surgery, your incisions will be closed with stitches and covered with a dressing (bandage). Usually arthroscopic ACL reconstruction surgery is done on an outpatient basis. Typically you will go home the same day followed by a course of physical therapy. You will be able to remove the bandage and shower 2 days after surgery. The small incisions will simply be covered by a band-aid.

Graft Choice
Grafts can be obtained from several sources and there are advantages and disadvantages to all graft sources.

Hamstring tendon autograft.
The semitendinosus and gracilis hamstring tendons on the inner side of the knee are used in creating the hamstring tendon autograft for ACL reconstruction. This creates a four-strand tendon graft that has shown to have fewer problems associated with harvesting of the graft compared to the patellar tendon autograft including: no anterior knee pain or kneecap pain (compared to patellar tendon), less postoperative stiffness, smaller incisions, and faster recovery.

The graft function may be limited by the strength and type of fixation in the bone tunnels, as the graft does not have bone plugs. There have been conflicting results in research studies as to whether hamstring grafts are slightly more susceptible to graft elongation (stretching), which may lead to increased laxity.

Hamstring Tendon Autograft

Allografts
Allografts are grafts taken from cadavers and are becoming increasingly popular. These grafts are also used for patients who have failed prior ACL reconstruction and in surgery to repair or reconstruct more than one knee ligament. Advantages of using allograft tissue include elimination of pain caused by obtaining the graft from the patient, decreased surgery time and smaller incisions.

The achilles and patellar tendon allografts allow for strong bony fixation in the bone tunnels with screws. However, allografts are associated with a higher risk of infection, including viral transmission (HIV and Hepatitis C), despite careful screening and processing. There have also been conflicting results in research studies as to whether allografts are slightly more susceptible to graft elongation (stretching), which may lead to increased laxity.

Patellar Tendon and Achilles Allografts

Rehabilitation
Whether your treatment involves surgery or not, rehabilitation plays a vital role in getting you back to your daily activities. A physical therapy program will help you regain knee strength and motion.

If you have ACL surgery, physical therapy first focuses on returning motion to the joint and surrounding muscles. This is followed by a strengthening program designed to protect the new ligament. This strengthening gradually increases the stress across the ligament. The final phase of rehabilitation is aimed at a functional return tailored for the athlete's sport. Because this re-growth takes time, it may be six months or more before an athlete can return to sports after surgery.

For more detailed information about ACL Reconstruction please visit: AAOS Online Services Fact Sheet - ACL Injury: Does It Require Surgery?

Dr. Samimi is a southern California ACL surgeon offering ACL surgey at 3 location in West Covina, Encino and Brentwood / West LA.