The anterior cruciate ligament (ACL) is one of the stabilizing ligaments in the knee. It's main job is to prevent translation of the tibia (shinbone) relative to the femur (thighbone). When the ligament has been torn, the tibia tends to "buckle" and translate. The consequence of this is potential damage to either the meniscus, or shock absorber of the knee, or the cartilage, or smooth lining of the knee. If the meniscus gets torn in this process, pain and/or locking of the knee may occur. Surgical treatment may be necessary. In the setting of a knee without a functioning ACL (ACL deficient knee), the torn portion of the meniscus that is symptomatic will need to be removed. The removal of this shock absorber has been shown to predispose the cartilage to premature wear, or arthritis.

The ACL connects the femur to the tibia, and prevents anterior (front) and rotational translation of the tibia relative to the femur. The image below depicts a normal ACL.


Tearing of the anterior cruciate ligament can occur in a number of settings. We might envision these ligaments getting damaged from higher energy athletic activities such as a fierce tackle on the football field or a major skiing wipeout. However, lesser events such as pivoting on the basketball court or jumping from a step stool more frequently tear the ligament. Violent injuries such as motorcycle injuries not only injure the ACL, but often numerous other major ligaments.
The tearing episode often will create a feeling of a "pop" in the knee. The knee often will not be too painful initially, but subsequently will swell massively over the following few hours. Bending and walking will be painful. As the swelling improves, the knee often will not hurt giving a false impression everything is ok. The main complaint following this is repeated buckling episodes or periods of giving way.


Typically, the description of how your knee was injured in conjunction with your office examination makes the diagnosis fairly straightforward. If you present with a massively swollen knee, it may be useful for me to aspirate your knee. This not only will make your knee feel better, but also gives me diagnostic information regarding the cause of the swelling. MRI scans are useful to confirm the diagnosis and help evaluate the status of the meniscus, cartilage, and ligaments of the knee.


Unlike many other ligaments, the ACL does not heal once it is torn. Therefore, rehabilitation combined with bracing or surgical reconstruction are the two reasonable options. Rehabilitation, or physical therapy, focuses on improving the quadriceps and especially the hamstring muscles strength. Small nerves inside our knees get short circuited with the initial injury and often don't recalibrate without professional rehabilitation. Return to high demand activities (certain occupations and athletics) often will require a custom brace in conjunction with therapy. Unfortunately, the results of rehabilitation and bracing are relatively unpredictable. Surgical reconstruction of the ligament is the other alternative to therapy. In this setting a new "ligament" is placed where the prior ACL had been. Good results can be obtained using either method. Every patient is different, and it is an individual decision which way to proceed.


Cutting, twisting, jumping, and pivoting activities place an enormous amount of stress on the knee. Heavy manual labor involving lifting and aggressive sports often can cause an ACL deficient knee to buckle despite our best efforts at physical therapy and bracing. Individuals falling into these categories should seriously consider an ACL reconstruction. High demand sports include football, rugby, basketball, volleyball, wrestling, skiing, hockey, gymnastics, tennis, lacrosse, softball, and baseball.


Walking, swimming, biking, and straight forward jogging are activities usually able to be performed without buckling episodes in an individual without an ACL. Desk jobs are the classic example of a low-demand occupation. Individuals meeting this description often are very successful in succeeding with rehabilitation of the knee.


Meniscal tears commonly accompany ACL injuries. Meniscal tears can range anywhere from minor to major injuries. Typically, very few meniscal tears are amenable to fixing. Blood supply is necessary for our bodies to heal any injury. The meniscus only has blood supply to its outer third. Therefore, tears located only within this outer third can heal. If portions are outside this region, then any attempt at fixing the meniscus is doomed to failure since there is no blood flow. Most meniscus tears are degenerative in nature (due to wear and tear), and are located in patterns that won't heal. However, those occurring with the first episode of buckling many times are contained within this peripheral, or vascular, portion of the meniscus. It therefore is possible to fix this meniscus if surgery is not delayed. One concern with delaying surgery for a prolonged period of time is that tears can either become larger or the torn portion can become so damaged that it is not likely to heal. The decision to repair a meniscus will be made at the time of the ACL reconstruction. If the torn portion is removed, the amount of meniscus resected is directly proportional to the risk of premature wear of the cartilage.


Meniscal repair is performed at the same setting as the ACL reconstruction. One advantage of doing these simultaneously has been an improved healing rate of the meniscus. Approximately 90% of repaired meniscal tears heal while performing an ACL reconstruction versus a 50-75% healing rate without reconstructing the ligament. This improved healing rate is attributed to extra blood flow within the knee as a result of the reconstruction. Those unfortunate individuals with a meniscal repair that doesn't take may require a second operation to remove the torn portion. While no one wishes to have a second operation, the benefits of preserving the meniscus far outweigh the inconvenience and risks of a second operation.


Four major ligaments stabilize the knee: the anterior cruciate ligament; the posterior cruciate ligament; the medial collateral ligament; and lateral collateral ligament. If one of the other three ligaments has been completely torn in conjunction with the anterior cruciate ligament, the knee will typically be so unstable it will affect all activities. Therefore, surgery usually will be necessary. It should be stressed this is for torn ligaments, not mild sprains.


The thought process here is: "We can't change the past, but we can change the future." The decision boils down to the risk/reward ratio of surgical reconstruction versus bracing and therapy. This is one of those odd situations where surgery is actually the more conservative treatment especially for the younger and more active patient. The risk of the knee being worse after surgery is highly unlikely, and the risk of the reconstruction failing is under 10%. On the other hand, there is at least a 50% or higher failure rate for rehab and bracing alone for a younger, higher demand individual. All is takes is one bad buckle for there to be permanent damage either from a torn meniscus or damaged cartilage. I feel strongly every adolescent and young adult should consider immediate surgical treatment for a torn ACL rather than tempting fate.


· Athletes involved in twisting, pivoting, jumping sports (high risk activities)
· Heavy laborers (high risk activities)
· Individuals with buckling during daily activities despite physical therapy
· Repairable torn meniscus
· Multiple ligaments torn


Timing of surgical reconstruction varies on an individual basis. One of the major complications of ACL reconstruction is a stiff knee. The one factor we can control in preventing this is ensuring your knee is "ready" for surgery. Typically, this will be a knee that has no redness, minimal swelling, and has virtually all of its motion. Usually, there is no rush to performing the operation (although we want to get on with our lives). Certain situations may push us sooner than later to operate. These include torn meniscus, multiple ligaments injured, and a "locked" knee.


There are three tissue choices for your new anterior cruciate ligament: patellar tendon; hamstring tendon; and allograft. Each has advantages and disadvantages. The best graft selection will vary from patient to patient and occasionally I will feel very strongly a certain material should be used. However, usually all three choices would work equally well. THE SUCCESS RATE OF ALL THREE IS IDENTICAL IN PREVENTING BUCKLE EPISODES AND PROTECTING THE MENISCUS AND CARTILAGE FROM FURTHER INJURY!!!!!

Patellar Tendon

The central portion of our patellar tendon along with its attachment to the patella (kneecap) and tibia (shinbone) is removed in one piece. The advantage of using patellar tendon is the bone plugs attached to the tendon are able to heal at a faster rate than those of the hamstring graft or allograft. The patellar tendon and bone has been shown to regenerate itself so the loss of strength is minimal. There is the least amount of loosening of the patellar tendon graft than the other choices. The major disadvantage of this graft selection is anterior knee pain. Approximately one in four individuals can have serious pain at the front portion of their knee for up to two years, with a much smaller portion even longer. Very small risks unique to this include patella fractures, stiff fat pads, and painful bone spurs.

Hamstring Tendon

Two portions of our hamstring (gracilis and semitendonosis) tendons are removed from their attachment on the tibia and the muscle is pushed away from the tendon. It is common for patients to have some muscle spasms, minor calf/foot swelling, and bruising of their ankle or foot following this operation. The main advantage of this graft choice is the avoidance of the risk of anterior knee pain as seen with the patellar tendon. In addition, the surgery can be performed through a smaller incision and be less painful initially than the patellar tendon. The main disadvantage of this graft choice is the body must heal this ligament bone to tissue (as opposed to bone to bone). In a small percentage of patients, the tunnels in which this healing occurs get wider and can cause some loosening of the ligament. The other disadvantage is a small loss of hamstring strength. Unless you're a very high level high jumper, hurdler, or pole vaulter, the loss is negligible. Finally, removing the hamstrings surgically can be challenging and occasionally the graft can be inadequate requiring another alternatives.


Allograft is donor tissue. This is taken from a cadaver, and frozen after being tested for disease. Allograft choices include patellar tendon, Achilles tendon, and tibialis tendon. The main advantage of allograft is the least amount of trauma done to the knee since no graft material is harvested. Therefore, patients receiving allograft probably have the least pain of all graft selections. Bone to bone healing occurs with this, although similar to hamstring a slight bit of loosening occurs. The main disadvantage is the potential for a type of rejection that can occur in 1-2% of people. This is manifested by an occasionally swollen knee. The most feared complication would be disease transmission (HIV, hepatitis). Although real, this risk is exceedingly small. Finally, this graft choice is extremely expensive.

To summarize (in my opinion)(1 is best; 2 is next best; 3 is worst):

Graft Function Initial Pain Cosmesis Anterior Knee Pain Micro-loosening Disease Transmission Failure Rate
Patellar Tendon 1 3 2 2 1 1 1
Hamstring 1 2 1 1 2 1 1
Allograft 1 1 1 1 2 2 1


I perform the majority of my ACL reconstructions at Ravine Way Surgery Center. Occasionally, due to insurance or medical considerations, the reconstruction also may be performed at Evanston or Glenbrook hospitals. This typically is done as an outpatient.


Your choice of anesthetic is a decision between you and the anesthesiologist. The two options typically are either a general anesthetic or a spinal. This operation does not lend itself to being performed under local. The length of surgery can be variable depending on the status of the meniscus and cartilage, and therefore most patients elect to have a general anesthetic since they can be rapidly awaken after the surgery is completed compared to a spinal that either could run out or leave one without feeling for an extra hour or two after the surgery is over. A femoral nerve block may be used to augment your anesthetic. This is where the anesthesiologist may inject long acting local by nerves supplying a pain sensation to your thigh and knee.


You will receive three medications following your surgery.
1) Narcotic (Norco; Vicodin)-take as needed for pain
2) Vistaril-take as needed for nausea
3) Anti-inflammatory (Toradol)-take these as directed on a regular basis until they are completed. The day following their termination please take one aspirin a day until your two week follow-up visit to prevent the development of blood clots.

Everyone will have their wounds and knee injected with long acting local anesthetic following the operation. Some insurance companies will cover a special ice bandage/machine further assisting in pain control. Please discuss this with my nurse if you have an interest.


The bandage should stay on the knee for 48 hours following surgery. The outer bandage (ace bandage and padding) should be unwrapped. The pain catheter should be pulled out of the skin. This is not painful. Discard these. There will be stitches and small band aids (steristrips) covering the incisions. Leave these along. Place fresh gauze over the incisions for the first few days. You may shower after you remove the bandage from surgery. Put gauze and tape over the incisions and then cover these with saran wrap. After the shower, remove the gauze and saran wrap and replace fresh dry gauze. A rule of thumb to live by for the first week, keep the wound clean and dry.


You will be given a knee immobilizer after surgery. You can place as much weight as comfortable on your knee with the brace on. While laying down, I want you to bend your knee as much as possible. In addition, prop your heel on a few phone books and pillows to let gravity work on straightening the knee. Ice your knee after these exercises. If you have had a meniscal repair, I will let you know not to bend your knee past 90 degrees.


Physical therapy typically will begin within days following surgery. A presurgical visit with the therapist not only will help you with your motion and strength before surgery, but also will educate you on what to expect after surgery and have the immediate postsurgical visits scheduled. The initial visits following surgery work to regain your knee's motion. Subsequently, they will work on strengthening, nerve retraining (proprioception), and eventually return to sport activities. You will be able to discontinue your knee immobilizer when your quadriceps awakens following surgery (usually two-three weeks). You should not do any twisting, pivoting, jumping, jogging, or running unless specifically instructed by your therapist for six months. You will be walking immediately following surgery with biking (about six weeks postoperatively) and jogging (about nine weeks postoperatively) beginning soon after. Although your knee may feel ready for athletics sooner, do not return to a high demand activity without my approval. The implanted graft weakens as our bodies transform the graft into ligament. The weakest point is approximately three months following surgery. The graft resumes the desired strength at five to nine months postoperatively, and this is the rationale for holding off on returning to high demand activities for at least five to nine months. In the lab, patellar tendon autograft incorporate most rapidly, with hamstring autograft next, and allografts may take nine months to incorporate.


Risks shared with other procedures include wound healing complications, infection, and risk of anesthesia. Knee stiffness is an infrequent, although devastating, complication. Surgery may be delayed from your initial injury to prevent this. There is a small risk of blood clots to the legs or lungs with this operation. Prior history and birth control pills are the two most identifiable risks. You will be on an aspirin a day to help prevent this. Many patients will notice a numb area on the outside of their knee following surgery. This will not hurt. This is because some small nerves crossing the incision site get damaged in the surgery. Unfortunately, this is unavoidable and usually doesn't return. The chance of the graft rerupturing is very slight if you follow your therapy to the letter.


You will be allowed to return to your desired activities after I have given you clearance. Typically, this occurs at 6 months. If an individual wishes to pursue a high demand activity at this point, I will recommend a brace be worn for the first 6 months back. This can be arranged through my nurse. I also recommend a strength test for your hamstrings and quadriceps to ensure you have achieved a strength level so your muscles can help protect your reconstructed ligament as well. One year following your surgery you can discontinue the brace. Enjoy sports and return to work without fear of reinjuring your knee. In fact, you probably are more likely to injure your