FAQ - What is the ACL ?

Q :		What is the ACL?
A :		There are two large ligaments inside your knee each about the size of your little finger that cross deep inside the joint. They are called the ACL (anterior cruciate ligament) and PCL (posterior cruciate ligament) and go from the femur (thigh bone) to the tibia (shin bone). They serve to stabilize the knee and allow it to glide through a smooth range of motion as you bend and straighten the leg. The ACL is the ligament in the front and the one most commonly injured.

Q :		Why is it important?
A :		Without the ACL the knee is less stable. Without its stabilizing influence, the knee can buckle suddenly as it is used and this leads to cartilage damage and eventually to arthritis. This is usually not a problem for "straight-ahead" activities such as walking or jogging. However, it can be a big problem for activities involving twisting, pivoting, jumping, or suddenly changing direction. Examples of these activities include most sports (especially basketball, football, volleyball, soccer, skiing, etc.) and many jobs (such as carpentry, warehouse, refinery, etc.).

Q :		Is anything else damaged inside my knee?
A :		About half the time when the ACL is torn there is also damage to the meniscus cartilage inside the knee. If present, this is something that can be taken care of at the same time ACL surgery is performed. You can usually tell whether there is a torn cartilage on examination but sometimes this is difficult. Occasionally, an MRI study can help but this is expensive and time consuming and usually is not necessary.

Q :		What would happen if I did nothing about this injury?
A :		Usually within weeks of tearing the ligament, the pain and swelling go away and the knee starts to move well. The knee usually starts to feel nearly normal. The problem comes when you try to cut, pivot, ortwist on the knee. Without the stabilizing influence of the ACL it will likely buckle and give way. Patients usually end up with a "trick knee" that gives way unexpectedly. The problem with this (beyond the embarrassment) is that with each episode of buckling, the joint gets scuffed and cartilage often tears leading to arthritis. Former President Gerald Ford is a good example. He used to trip and fall frequently because of this same injury which he sustained playing football at Michigan. He was fine walking but whenever he tried to twist or turn suddenly his knee would buckle. He never had it fixed (the current surgery didn't exist) and ended up with bad arthritis and a knee replacement a few years ago. Some people who elect to live less active lives (no jumping, cutting, pivoting, running sports) can get by without this ligament. Currently, the conservative way to treat the injury is with reconstructive surgery, if you plan to remain active in agility sports (basketball, football, volleyball, skiing, etc).

Q :		How is the ligament fixed?
A :		Older techniques consisted of sewing the torn ends of the ligament back together. This relatively simple operation didn’t work and the ligament almost always tore again. The standard operation is now reconstruction of the ligament where a tendon from your own body is used as a replacement for the anterior cruciate ligament. There are two choices for this substitute tendon. I used to use the central third of the patellar tendon (the tendon which runs from the knee cap to the shin bone). However, a new technique using the hamstring tendons from behind the knee is just as strong and less painful. The recovery is quicker and there are fewer complications. This is now my graft of choice. Using arthroscopy, I place the tendons where the ACL used to be, secure them with screws, and this becomes the new ligament. Cartilage tears are repaired at the same time. Shortly after the surgery, your knee will be in a continuous passive motion machine (CPM). This is essentially a hammock for your leg which gently bends and straightens the knee. Most patients use this for approximately one week after the surgery.

Q :		Will I have to stay in the hospital?
A :		I have done this as an outpatient but most patients stay overnight and go home early the next morning. Everything is done arthroscopically (through small poke holes) except for harvesting the patellar tendon or hamstring graft which requires a short incision on the front of the knee.

Q :		Do the screws ever come out?
A :		Almost never. They are actually inside the bone and rarely cause any discomfort.

Q :		Doesn't this weaken the hamstrings?
A :		There are five hamstring tendons. I use two. The remaining three compensate by getting stronger and there is some evidence that the two tendons regrow so you won’t miss them.

Q :		Will I need a brace?
A :		This reconstruction is strong enough that you rarely need a brace for more than a few weeks to a month. There are a couple of exceptions. The most common is when the MCL (along the inner aspect of the leg) is torn at the same time. Patients need a brace for four to six weeks when the MCL and ACL are torn together. I often recommend a "sport brace" during the early phases of physical therapy, much like many football players wear on the field.

Q :		When can I walk on my leg after surgery?
A :		You walk the same day as the surgery. You are given crutches but should put your weight on the leg right away. People frequently end up carrying the crutches by the end of the first week but I want my patients to use them until they can walk without a limp.

Q :		Will I need rehab or physical therapy?
A :		Yes, this is very important. Your chance of achieving normal knee function after the surgery is greatly increased by the proper rehab. In fact, it takes a great commitment from the patient to get to the therapist and do the exercises with the appropriate diligence. It is also important to do only the correct exercises, as doing the wrong exercises can be more damaging than doing none at all. Unless otherwise instructed, you should start supervised physical therapy 1-2 days after your surgery. At first, PT emphasizes obtaining your full range of motion and some strengthening exercises. As your motion improves, more emphasis is placed on strengthening. Usually within a week you are on a stationary bike and gradually progressed to a stair climber. You will also be doing some weight lifting exercises such as mini-squats and leg press. I usually recommend therapy 3-5 times a week for the first 1-2 weeks and 3 times a week for 2-4 weeks and gradual transition to a home or gym-based program. Jogging is usually allowed at approximately 2-3 months if your motion and strength allow. There is a gradual return to sports with shooting baskets at 2-3 months, golf at 2-3 months, and so on. Full-speed sports are usually allowed at 5 months assuming your strength and agility have returned to near normal.

Q :		What do I have to do to get my knee ready for surgery?
A :		The amount of swelling and stiffness you experience after surgery is related to the amount of swelling and stiffness you had before surgery. In other words, it is important to get rid of as much swelling and stiffness as you can before the operation. If the injury is old, your knee may bend well and have no swelling in which case you're ready for surgery already. Usually when the injury is a new one, there is a lot of swelling and stiffness and you need "prehab" to prepare your knee for surgery. This consists of exercises and icing which enables your knee to be in the best possible shape (full motion and no swelling) for surgery. "Prehab" is also beneficial as it gives you a chance to familiarize yourself with some of the exercises you'll be doing in the early postoperative period.

Q :		When can I go back to work?
A :		This depends on what type of work you do. Usually desk work can resume after three to five days. Jobs requiring significant amounts of walking can usually be return to after two or four weeks when you feel comfortable off crutches. It's usually a couple of weeks before you can drive safely. You can't really climb or push/pull heavy loads for up to three months. Those jobs need to be avoided for awhile. Again, all of this is variable as everyone is different.

Q :		Risks of surgery (possible, but still uncommon)
A :		The most frequent problem is stiffness. That is why I want your knee to be flexible beforehand, and why you need to use the CPM machine and attend physical therapy. I fully expect you to have your normal motion when your rehabilitation is complete. Blood clots are also possible, but rare (less than 1%). You will have a stocking on your leg to minimize swelling and lower your chances of getting a blood clot in your leg. Keeping your leg mobile also decreases this risk. Infection also is rare, but possible. We sterilize your leg and use antibiotics to prevent this. It is possible to stretch or retear the graft. For the first five months the graft is weak, so you will need to avoid twisting/cutting activities. Even after the graft is mature, you can still tear it. You tore the ligament God gave you so you can tear the one I give you too.