ACL Reconstruction


Role of the Anterior Cruciate Ligament


The ACL stabilizes the knee when jumping, pivoting, or cutting. It prevents the shinbone (tibia) from sliding forward on the thigh bone (femur). ACL tears often occur when the foot is planted and there is a twist to the opposite side. ACL tears can also occur when landing from a jump. When the ACL is torn, it can feel like a “trick knee” that will give out or give way unexpectedly.


If the knee is destabilized by a torn ACL, injury to the shock absorbing cartilage (the meniscus) can result. Locking of the knee and arthritis can occur.


Treatment of ACL tears


Some people with ACL tears will do well without surgery, depending on the age and activity level of that individual. However, most younger or more active individuals will require surgery to stabilize the knee. There are no hard and fast age limits or activity limits to decide when ACL reconstruction is necessary.


Initial treatment of ACL tears is the same for everyone; the goal is to return the knee to a near normal state. The goal is to eliminate swelling, restore full range of motion, and resume walking without a limp. This may take 2-6 weeks. Past experience has shown that reconstructing the ACL before these goals are achieved results in stiffness and scarring.


ACL Reconstruction


Once the ACL is torn, it cannot be successfully sewn back together. To restore stability, the ligament has to be reconstructed with tissue from somewhere else (a graft). The graft can be taken from the same knee, and typically a piece of the patellar tendon is utilized. The patellar tendon attaches the kneecap to the shinbone, and is usually 3 cm wide; the central third is utilized. Some patients will opt to use a cadaver donor of the patellar tendon (allograft) rather than using their own tissue (autograft).


There are risks associated with everything we do in life. Surgery is no exception. The complications of ACL reconstruction include (but are not limited to):


  1. Bleeding. Not usually a significant problem; a tourniquet is used to minimize blood loss.
  2. Infection. Antibiotics are given through the IV prior to surgery to reduce this risk.
  3. Blood clots. This risk is rare but can be serious or fatal. This risk is reduced by exercising your legs and walking.
  4. Stiffness. Having full range of motion before the surgery reduces this risk; performing exercises after surgery also helps regain motion. Rarely, people can require a second surgery to remove scar tissue.
  5. Fracture of the patella or rupture of the patellar tendon. This is rare, and usually results from falling directly on the knee after surgery. This risk is eliminated if allograft (cadaver donor) tissue is used.
  6. Numbness around the incisions. There are small nerves that are unavoidably cut when making incisions. An area of numbness around the scar is common, and gradually decreases over 12 months. It may be a permanent small numb patch in about 50% of patients, though most people are not bothered by it.
  7. Graft rupture or recurrent instability. 3%-7% of patients can retear their rebuilt ACL. Following the rehab protocol and avoiding return to sports until the knee is fully rehabbed can reduce the risk of retear.


Before Surgery


For 7-10 days before surgery, stop taking aspirin and anti-inflammatory products like ibuprofen (Motrin) because they can increase bleeding during surgery. Tylenol is safe to take as an alternative pain medication. Dr. Burns may order bloodwork or EKG depending on age and health.


Day Before Surgery


Have nothing to eat or drink after midnight the night before surgery. If you have a fever or cough, please call Dr. Burns’ office at 314-291-7900.


Day of Surgery


Check in to the surgery center or outpatient surgery area 90 minutes before your scheduled procedure. You will receive an IV and medication to relax you if necessary. The surgery is done under general anesthesia; you will be asleep during the surgery.


You will spend 1-2 hours in the preoperative area; the surgery itself will take 1-2 hours; you will then go to the recovery room for 1-2 hours. You will need someone to take you home. The incisions will be covered with small white tapes called steri-strips, which you should leave in place until they fall off by themselves. You will have elastic stockings and an ice pack wrap on your knee, and you should keep your knee iced at all times except when doing bending (flexion) exercises. Keep the elastic stocking and ice pack wrapped snugly, as the compression will reduce the swelling. Our goal is to minimize and prevent swelling rather than treat it after it occurs.


Going Home After Surgery


You will begin rehabilitation of your knee as soon as you arrive home. A CPM (continuous passive motion machine) will be delivered to your home; this machine gently bends and straightens your knee to reduce stiffness. The machine also keeps your leg elevated above your heart to reduce swelling. Your leg should be in the CPM at all times for the first 2 weeks except to shower, bathe, do exercises, or go to the bathroom. It is recommended that you sleep in your CPM for the first week.


You may remove your dressing 48 hours after the surgery and shower if the incision is dry and not oozing (no drainage). Some blood on the steri-strips is normal. You may shower with the incision uncovered and pat dry. Do NOT soak in a tub.


Wear your TED hose for the first 2 weeks, as this will provide compression and reduce swelling in the knee. You should use the ice wrap as much as possible for the first 2 weeks.


You can put as much weight as feels comfortable on the operative leg. However, most people prefer to use crutches for support during the first 1-2 weeks. Putting weight on your leg will not hurt the reconstructed ligament, but the more time you spend up and about the more swelling and pain you may experience.


You can eat any type of food that you like. Remember that the pain medication and anti-inflammatory medication can cause nausea or irritate the stomach. It is best to take these medications with food and to start with small portions.




After surgery, you will be given prescription medications. Please take these as directed.


Pain medication.  You will be given a pain medication to take as needed after surgery, usually hydrocodone (Vicodin) or oxycodone (Percocet). You may take one or two tablets every 4-6 hours as needed for pain.

Toradol. Toradol is a powerful anti-inflammatory medication that you should begin the day after surgery. Take one tablet 3 times a day for 4 days. Take all the medication as prescribed. When you have finished the medication, you may begin to take ibuprofen as needed for pain and inflammation.

Ibuprofen. Ibuprofen is an anti-inflammatory medication and can be taken up to three times a day as needed for pain, swelling and inflammation.




Perform these exercises every hour while awake for the first 2 weeks. It is extremely important that you start these exercises as soon as possible and perform them regularly. Early rehab prevents stiffness and allows you to return to normal activities including work and school. Average return to sport is 5-6 months. If you are not sure how to do the exercises, look on the website, There is no excuse for not doing your exercises!


  1. Heel Props for 10 minutes. Prop your heel up on a rolled up towel, and allow gravity to straighten your knee.
  2. Quad sets, 10 times. With your leg straight, try to push the back of your knee into the bed and fire your quadriceps muscle.
  3. Straight leg raises 10 times. With your leg straight, lift your heel off the bed a few inches, then lower down.
  4. Towel stretch 10 times. With your knee straight, wrap a towel around your toe and gently pull, stretching and straightening the knee.


Perform these exercises every other hour while awake for the first 2 weeks.


  1. Heel slides. Gently allow your surgical leg to slide toward you until your knee bends and reaches at least 90 degrees.
  2. CPM flexion to 115 degrees. Increase the flexion on your CPM to 115 degrees, hold for 5 minutes.



Please call for the following symptoms:


  1. Fever greater than 101 degrees.
  2. Significant increase in swelling in the knee.
  3. Increased drainage from the knee.
  4. Increase in soreness or pain that is not relieved by the medications.
  5. Upset stomach, nausea or vomiting.
  6. Difficulty sleeping.