Patient Guide to Anterior Cruciate Ligament (ACL) Surgery

What is the anterior cruciate ligament?

The anterior cruciate ligament (ACL) is one of the most important ligaments in the knee joint.  Unfortunately, it is also one of the most commonly injured.  There are essentially four main ligaments to the knee joint – the anterior cruciate ligament, the posterior cruciate ligament, and a ligament on the inside part of the knee and a ligament on the outside part of the knee.  The ACL is one of the two ligaments that is in the middle of the knee and is responsible for preventing the shin bone from moving forward on the thigh bone.  Once the ACL is torn, the knee will have laxity demonstrated on the physical exam with a lot of “play” in the knee.  Typically, this laxity then will lead to instability of the knee when patients are active.  Some patients experience instability only when they play sports and some people experience it on a daily basis.  The likelihood of a patient experiencing instability is very high, especially when they are young and they are active.  The activity level though is the number one factor that determines whether a person will have instability or not.  Some patients may avoid a lot of cutting and turning activities to prevent instability and sometimes choose to do this rather than have surgery to reconstruct the ACL. 

What is an ACL reconstruction?
Once the ACL tears, it occurs in a way that makes it impossible to repair with sutures or other means.  Usually the torn ACL is “stretched out like taffy” and then has two separate ends that cannot be repaired to each other.  Therefore, a reconstructive procedure has to be done in order to duplicate the ACL’s characteristics.  This is done through an arthroscopic-assisted procedure where we will use new tissue (usually a portion of the patella tendon or a portion of the hamstring tendons) to put reconstruct a new ACL.  This new tissue is actually stronger than the native ACL.  This tissue then has to go through a healing phase where the bone tunnels that we make for the procedure will heal in with bone and the new tissue will become a new ligament.  This is the primary reason why the rehab and the length of recovery is so long.  Incisions have to be made in order to harvest the tissue to use for the new ligament, but the remaining procedure is arthroscopic.  I strive to use very small incisions in order to harvest the graft material for the new ligament, and therefore help with post-operative pain and also minimize significant scarring.  Often there are other injuries involved with an anterior cruciate ligament tear, such as meniscus tears or cartilage injuries.  During the arthroscopic component of this procedure, these injuries will be addressed as well. 

What are some of the possible complications of surgery?
While complications are not common, all surgery has associated risks.  Possible complications include stiffness of the knee after surgery or continued pain.  The use of arthroscopic techniques attempts to limit these complications.  Other complications include infection, bleeding, nerve damage, blood clots, or problems with the anesthesia.  If a meniscus repair is performed, it is possible that the torn area will not heal.  This would require a second surgery to remove the torn meniscus.  Even though this is possible, it is better to attempt to repair a meniscus that may heal, in order to preserve the normal meniscus function.

What kind of anesthesia is used?
Knee arthroscopy can be performed with general anesthesia (going to sleep), or regional anesthesia (spinal or epidural block).  The type of anesthesia will depend on your choice.  The anesthesiologist will discuss your options the morning of surgery.  The anesthesiologist will talk to you about a femoral nerve block.  This is a numbing procedure to one of the main nerves that supplies sensation to the knee and is very helpful for pain control for the first 18 to 36 hours.  I would highly recommend patients undergoing this and certainly I would choose to have this if I was to have this procedure.

What do I need to do to prepare for surgery?
Our staff will help to set up the surgery through your insurance company and will instruct you on any paperwork that may be necessary.  If you are over the age of 50, or have significant health conditions you may require an EKG and chest x-ray.  You may also need to see your internist or family doctor to obtain a Letter of Medical Clearance.  The day before the surgery, a member of the hospital or surgery center staff will contact you about what time to arrive for surgery.  You may not eat or drink anything after midnight before your surgery.

How long will I be in the hospital?
ACL reconstruction is almost always an outpatient procedure, where you will go home the same day. 

What happens the day of surgery?
The day before surgery you will be told what time to report to the hospital or surgery center.  You will be admitted and taken to a pre-operative holding area where you are prepared for surgery.  You will be asked several times which extremity I am operating on.  Please note that you are asked this question many times on purpose.

After the operation you will be taken to the recovery room to be monitored.  Once the effects on anesthesia have worn off and your pain is under good control, you will be given your post-operative instructions and prescription for pain medication and released.  Please be aware that the process of getting checked in, prepared for surgery, undergoing the operation, and recovering from anesthesia takes the majority of the day.  I would recommend that you and your family members bring along some reading material to make the process easier for all.

How should I care for my knee after surgery?
Prior to your discharge, you will be given specific instructions on how to care for your knee.  In general you can expect the following:

You will be given a prescription for pain medication and an antibiotic. You also will be asked to take one regular Aspirin (325mg) a day.  You may also supplement the pain medicine with Advil or Aleve.   

You may not shower until we see you back on post-operative Day 3.  On that day your dressing will be changed, the brace protocol will be explained to you, and you may shower at that point.  If you really need to take a shower prior to this, then you need to use a garbage bag to seal over the brace and the dressing and be very careful that you do not get it wet.   

You will be instructed how to use crutches before the surgery.  You should bring a set of crutches with you to the surgery.  Crutches are usually used by patients for the first week.  You may put weight on your knee as you feel comfortable, but typically people are using crutches in order to minimize some discomfort and until their leg becomes stable and their muscles start to return to function. 

We will put you in a brace after your ACL reconstructive procedure.  The brace will remain locked in the 0 position or held straight until you see us back on post-operative Day 3.  At that time we will reacquaint you with the brace and show you how you may start gentle range of motion.  You usually have the brace locked when you are walking with or without crutches for the first week.  You also need to wear it while you are sleeping for the first week.

Resume your regular diet as soon as tolerated.  It is best to start with clear liquids before advancing to solid food. 

You should apply ice over the dressing for 20 -30 minutes every hour for several days.  If your insurance company approves the use of a cold therapy unit, then this will be part of your dressing.  This is a very excellent tool to help minimize swelling and minimize discomfort.  Unfortunately, most insurance companies do not pay for this and if you would like one we can arrange it but there is a nominal cost.

Suture removal:
Some stitches are absorbable and do not need to be removed. However, if there are stitches they will be removed on your first post-op visit.

Return to work or school:
You can return to school or work anywhere from 2 days to 2 weeks.  If you return to work, it would be obviously in a sedentary type position because you would be using crutches and your brace would be on with your knee straight.  If your job involves more extended walking or heavy activity, you may be out of work or school for a longer period of time.

What will rehabilitation involve?
The rehabilitation is based on several goals: 1) allowing the tissue to heal; 2) regaining motion; 3) regaining strength; and 4) return to sports or work activity.  Formal physical therapy will begin typically on post-operative Day 4 or 5.  We will get you involved with a therapist that is very good at recovering people from ACL reconstructions, but also is close to your home.  I have a specific protocol that I will give the therapist to go over and help your knee come back to the best possible outcome.  The emphasis on early rehabilitation is on range of motion followed by the strengthening. 

When can I return to sports or full duty at work?
Your return to your desired activity level will depend on the extent of damage and the procedure performed on your knee.  In general, even the most strenuous jobs usually can get back to full duty somewhere between 8 to 12 weeks.  Certainly there would be caution with some cutting and pivoting activities.  As far as sports is concerned, the return is of longer duration due to the fact that the knee needs to have excellent motion, strength, and the ACL reconstruction also needs to acquire increased strength.  Approximately 90% of my patients get back to full sports activity in the 4 to 6 month window.  However, there are a few that get back sooner and there are a few that may take longer.  How quickly you return depends on several factors, including: 1) your own rate of healing; 2) the damage found at surgery; 3) if you have any complications; 4) how well you follow the post-operative instructions; 5) how hard you work in rehabilitation.