OUR ACL RECONSTRUCTION PROGRAM

Steve A. Mora, MD
Sports Medicine, Shoulder and Knee Specialist

You have sustained a major knee ligament injury called an ACL rupture. The letters ACL stand for anterior cruciate ligament. This ligament serves as one of the more important stabilizing ligaments in the knee and also one that is critical for any sport that demands cutting and pivoting. When the ACL is ruptured there may also be other associated cartilage tears in your knee that you must learn about. The injury is severe but the reconstruction can help you return to the same or close to the level of function prior to the tear. It is also fundamental to understand that when the ACL is torn it cannot be stitched together but rather must be substituted with a new "graft".

KNEE ANATOMY & FUNCTION

The Anterior Cruciate Ligament (ACL), posterior cruciate ligament (PCL, medial collateral ligament (MCL) and lateral collateral ligament (LCL) all serve is stabilizers of the knee joint by maintaining the anatomical alignment of the femur with the tibia. The bony surfaces of the joint are covered with a layer of articular cartilage that allows near-frictionless weight bearing and motion. The femur articulates with the lower portion of the knee, which is the tibia. The tibia is also covered with articular cartilage and has two semilunar fibrocartilages (medial and lateral menisci) that sit on its surface. Unfortunately, the menisci and cartilage have poor blood supply and poor healing capacity. About 25% of the time the articular cartilage is torn/injured and about 50% of the time there is a meniscus tear along with an ACL rupture. Articular cartilage repair is multifaceted and potentially complex but may include simple arthroscopic shaving and removing torn sharp edges to highly complex: drilling, plug transfers, and cartilage transplantation. The meniscus tear is either treated with removing the torn fragments or suturing it together if it is a clean cut. These procedures are performed concurrently with your ACL reconstruction in most cases.

CAN ACL RUPTURES BE PREVENTED?

ACL ruptures might be preventable in female athletes. Numerous theories have been proposed to explain the higher incidence of non-contact ACL injuries in female athletes compared to males, however, exact mechanisms and risk factors have not been adequately defined. In 1999, a group of experts pooled their efforts in an attempt to shed light on these important questions (Hunt Valley Conference on ACL Prevention Strategies) (1). Numerous variables were analyzed including environmental, anatomical, hormonal, and neuromuscular. The key risk factors were found to be diminished strength and neuromuscular control differences between male and female athletes. Additional information has also highlighted the importance of hip stability and pelvic control.
It is thought that female athletes have an imbalance of strength and power between the hamstring and quadriceps muscle around the knee (quadriceps dominance). Males have an average hamstrings-to-quadriceps ratio of nearly 70 percent (better balance between the hamstring and the quadriceps strength). The relative power of hamstrings in females is less than 50 percent and the time in which the hamstring contracts maximally is slower. In addition, men flex their knees naturally as they come down from a jump thereby protecting the ACL during the landing. Women tend to keep their knees and hips in a extended and less protected position. The lack of flexion and poor hip position predispose the knee to injury These, as well as a host of other less understood factors, are believed to "set-up" the female athlete for injury.

MAKING THE DIAGNOSIS OF ACL RUPTURE

The patient helps the physician in making the diagnosis by simply recounting the injury details. Most patients feel a "pop" as the ACL is torn and then they are unable to continue playing because of severe pain and swelling. The physical examination will usually show a positive "Lachman's and anterior drawer test". X-rays are always done to evaluate for bone injury, arthritis, and the possibility of fractures. The MRI allows characterization of normal and abnormal anatomy with excellent but not perfect accuracy. There are cases where the MRI is not "positive" but the specialist can sift thought the information and still make the diagnosis.

OK, YOU SNAPPED YOUR ACL, NOW WHAT?

First, the reconstruction for this injury is elective, meaning you do not have to make a decision today. The surgery is actually better if delayed a couple of weeks in order to allow the swelling to go down and the motion to improve. Secondly, you must decide if ACL reconstruction is necessary for you. Most athletes cannot cope with an unstable knee. Soccer, football, basketball, and volleyball players usually require a reconstruction. For some patients with a ACL rupture, even daily activities become impossible so you don't have to be a hard-core athlete to require surgery. There are however a few individuals who have been able to do some limited sports, sometimes using a brace, and not ever having have the surgery.

OPTION #1 The Conservative Approach (NO surgery)

The conservative option is best for those individuals who are lower demand athletes who do not do much sports and can cope with a loose or unstable joint. The treatment goal is to control the symptoms and progressively work towards full range of motion and strength. Surgery can be chosen later.

OPTION #2 - Knee Arthroscopy and NO ligament reconstruction

This option should be selected for those individuals who have a painful knee due to a meniscus tear but who do not desire ACL reconstruction. Once again, this equates to coping with an unstable knee and therefore limiting activities to a variable degree. This option is also frequently recommended for skeletally immature individuals (usually under 14 years) who cannot have a reconstruction because of potential damage to their growth plates. The patient will undergo a simpler surgery addressing only the meniscus tear. The ACL tear is left alone perhaps for a different day.

OPTION #3 - Arthroscopic ACL Reconstruction

This option is preferable for active individuals with a unstable knee. Reconstruction can stabilize the knee adequately and preserve pre-injury function in the majority of cases. This procedure has evolved over a 20-year period to a level that successfully returns athletes to sports 90-95% of the time. The procedure involves an outpatient surgery, general anesthesia, crutches for 2-4 weeks, and a immediate and long rehabilitation program with return to sports after 6 months. The new graft is secured with special biologic screws that dissolve in time. Most of the surgery is done "arthroscopically" meaning the incisions are kept small. We make every effort to incorporate minimally invasive techniques without compromising the reconstruction. The rehabilitation requires extensive exercise and commitment.

GRAFT SELECTION

There are several options for the ACL graft substitution. With all graft choices, the rehabilitation is started right away. Return to sports is usually the same for all grafts.

#1 Autograft Patellar Tendon Graft (taken from your knee) This is probably the most common graft choice world wide. It involves removing a central piece of the patellar tendon along with a little block of bone above and below. The patella tendon will eventually fill in the area that was removed. Harvesting this graft requires a 2-3 inch incision in the front of the knee. It is considered to be an extremely durable graft. There are situations that require use of the patella graft from the opposite knee such as damage to the patella tendon from injury or previous surgery.

#2 Autograft Hamstrings (taken from your knee) This technique utilizes the tendons in the inner back of the knee and leg. The incision is a little more towards the inner side of the knee but about the same size as the patella tendon. The overall success rate from this technique is similar to the patella graft however some surgeons worry about it stretching out. It is a little more cosmetic and probably leads to less kneeling problems. In our practice we do not utilize this graft because we are concerned about hamstring weakness and quadriceps dominance which have been implicated in ACL rupture risk in females.

#3 Allograft Tendon (cadaver/tissue bank) The use of the allograft or cadaver tissues in medicine has been gaining tremendous popularity. This is a good option in the low to mid level athlete or just the older (over 40) patient who is no longer abusing their knee. The advantages are: small incisions, most cosmetic, easier rehabilitation, less complications associated with the harvest of ones own graft and less pain after surgery. Several issues such as durability and safety are still being worked out by scientists. The success of this graft choice has been comparable to the other ACL graft options. Several studies have also documented efficacy and safety. Anytime the concept of allograft or human transplantation is discussed it is imperative to understand the probability of HIV, bacterial pores, and hepatitis transmission. All donors and specimens are comprehensively screened and negative results are documented prior to usage of the graft tissue. Newer and more efficient techniques are being employed by the tissue bank companies which have improved the risk of contamination. Also clinical "rejection" of the cadaver tissue has not been detected. The accepted probability for virus disease (HIV) trasmission is 1 in 1.5 million. More information can be obtained at the CDC web page.

WHAT ARE THE RISKS AND ADVERSE OUTCOMES OF SURGERY?
The risks below are uncommon but nonetheless must be fully understood. By accepting to have the surgery you also accept these risks. Some of these risks may be minimized by maintaining a healthy lifestyle, eating well, not smoking, controlling diabetes and following your doctor's instruction.

The list of possible risks is actually much longer, however those listed below are some of the more common risks. Please discuss any specific concern with your doctor.

Risks of anesthesia including death - As a general rule all anesthesia options are safe and effective. Regardless of the option selected, complication rates are very low. If you are healthy and able to exercise you should be able to tolerate general anesthesia without any problem. You will have a chance to speak to the anesthesiology before the surgery and make a well informed decision.

Major infection requiring more surgery including loss of graft. Most infections can be treated with short courses of antibiotics but there are cases where more surgery is necessary. In cases of severe, deep infection which is resistant to antibiotics, the new graft has to be surgically removed.

Recurrent knee looseness, graft failure, or screw loosening. Uncommon

Chronic Stiffness with Pain. The biggest problem following a reconstruction is inability to hyper-extend. This adverse outcome can be minimized with exercise compliancy and follow-up. Uncommon.

Major Nerve and/or Blood Vessel injury. Rare to have a major nerve or artery injury. Most of the time the skin immediately around the incision will be partially numb but this is not a significant issue.

Deep Vein Thrombosis (blood clots) with dislodgement into lungs. Extremely rare in arthroscopy.

Anterior Knee Pain- Some patients (about 5%) may have soreness in the front of the knee permanently when they kneel on it, especially with autograft patella tendon. This problem is minimized with good rehab.

WHEN SHOULD YOUR SURGERY BE DONE?

There have been several studies that recommend waiting 2-3 weeks and for the swelling to be down. This is also our practice. There is usually only one exception that demands sooner surgery and that is where there is a displaced meniscus tear that locks the knee not allowing any motion. In this case the surgeon has the choice of repairing the meniscus and then doing the reconstruction at a later date when the motion is better.

WHAT ARE YOUR ANESTHESIA OPTIONS

General: Widely accepted and used most commonly
Spinal/Epidural: Accepted but used infrequently.
Local: Not effective

WHEN CAN YOU PLAY AGAIN? THE ACCELERATED ACL REHABILITATIVE PROGRAM

Solid graft fixation of the graft allows early movement and weight-bearing after ACL reconstruction. Early exercise has been proven to be safe and effective. Walking begins immediately. Flexion and extension begins right away. Running usually at 3 months. The biggest problems patients have is obtaining full hyper-extension. Home exercises are done daily while physical therapy is done for up to 3-4 months. A "prevention program" is started at 5 months post-op. The "green light" for sports participation may be given as early as 6 months from surgery but the reality is that most patients are not ready to participate in these activities for 7-8 months. A national average is 9 months. Even after the "green light" is given, some patients will need a brace for 3-4 months while they get used to the new new mechanics. The good news is that after the long rehabilitation program, most patients are stronger that before the injury.

Please see our ACL rehabilitation program and the American Academy of Orthopaedic Surgeons site, aaos.org, for further information.

If there are any questions at any time, please ask. Remember that the purpose of this document is to educate and help you understand the complexities of your injury and its treatment as written by Dr. Mora. Every orthopaedic surgeon is different in their style, belief and preference. Other surgeons preferences are not necessarily wrong, just different, and probably just as effective. Good Luck.