ACL Tear

ACL Tear

What is an ACL Tear?

The ACL (anterior cruciate ligament) is the main anterior stabilizer of the knee. It is a strong ligament inside your knee that allows you to be able to turn, cut, twist and pivot.  There may also be other structures in your knee that are injured at the same time.  These may include your meniscus (fibrocartilage cushion in your knee), other ligaments, or the smooth articular cartilage on ends of bone.

The treatment plan will be influenced by the combination of structures that are involved, your current activity level and what your desired activity level will be. The final plan of care will be decided upon by you and your healthcare team.


What are the Symptoms of an ACL Injury?

The majority of ACL tears are complete tears or rupture that occurs when an individual makes a sudden cut or turn with feet planted in sports. In the MOON cohort of over 3000 ACL injuries, football, basketball and soccer make up about 70% of injuries.  The most frequent symptoms are shown below:


  • 70% hear or feel a pop
  • Majority of athletes don’t return to play
  • Swelling in the knee
  • Pain bending the knee
  • Feeling of instability or giving wayIf you suspect that you have injured your knee, seek out a qualified physician, physician assistant or nurse practitioner for an evaluation.



AC   =  articular cartilage

ACL =   anterior cruciate ligament

LCL =   lateral collateral ligament

LFC =   lateral femoral condyle

LTP =   lateral tibial plateau

MCL = medial collateral ligament

MFC =  medial femoral condyle

MTP =  medial tibial plateau

Anatomy of the Knee

This figure demonstrates the normal anatomy of your knee. The basic structure is a near frictionless hinge.  The hinge is held together by four ligaments.  The smooth, pain-free gliding surface is the smooth articular surface on the ends of the bone called articular cartilage (like the rubber on a tire).  The meniscus, or bushings, is designed to decrease the force of load on the articular cartilage.  Injuries that are effectively treated by arthroscopic surgery include meniscus tears, loose bodies, ligament injuries (especially to ACL) and microfracture to injured articular surface.    Your physician can discuss, in more detail, your findings and treatment  strategy.  Note: debridement of OA, or osteoarthritis, of the knee (i.e. fraying of the rubber on a tire) by itself is not an effective surgical treatment strategy.


Treatment Options:


Non-Operative Approach:

Some individuals who tear their ACL in an occasional recreational activity, may choose to have only rehabilitation to their knee and may elect not to have surgery. People who decide not to have surgery, usually don’t have a very active lifestyle or participate in sports that require a lot of cutting and pivoting.  Most people with this type of lifestyle will be able to function normally without having surgery to reconstruct their ACL.

Active individuals often question whether they should have surgery or wear a knee brace. Research has shown that custom and off-the-shelf braces do not protect against further knee injury in the athletic, active population.  If you and your physician choose a brace, please discuss the risks of additional knee injuries and the type of brace to be worn.

The immediate goal after an ACL tear is the same regardless of treatment options. Patients with isolated ACL tears are required to achieve normal walking, nearly full motion and strength and reduced swelling.


Operative Approach:

For patients that participate in cutting and pivoting sports like football, soccer and basketball, etc., especially at a competitive level, usually elect ACL reconstruction. ACL reconstruction has been shown to prevent re-injury or tearing of your meniscus cartilage.  However, a small percentage of patients with guided neuromuscular rehabilitation can function with ACL surgery but how to identify the individual is unknown.


Surgical Techniques:

Since a repair (or suturing together) of torn ACL fibers is not effective, another piece of tissue (graft) is chosen by you and your doctor to place within your knee using the arthroscope. Autograft means your own tissue.  These choices include your patellar tendon (the tendon from your kneecap to the bottom leg bone) or your hamstring tendons.  Allograft tissue comes from a donor.  These tissues include either a patellar tendon or other soft tissue including most commonly the hamstrings or Achilles tendon.

In younger, more active patients, especially those in competitive sports, either autograft (patellar tendon or hamstring) is the gold standard. Allografts should be avoided because of a three-fold higher failure rate.  The exact failure can be predicted from MOON cohort published results.

In scientific review of autograft choice, the graft does not influence outcome. Rather, the accurate placement by surgeons, stable initial fixation of the graft, patient compliance and rehabilitation are believed to optimize the results. The graphic below shows ACL retear rates based on age and graft type.



Your surgeon performs the surgery through the arthroscope. The skin incisions are only for the surgeon to harvest the graft, if you choose autograft, and drill tunnel at the original site of the ACL.  The graft is placed within the tunnels and fixed by a variety of choices to provide immediate stability prior to healing and to help stabilize the graft to the bone.


Pre-Operative Care:

If you will be having surgery, you will have an evaluation with a physical therapist who is a member of the team responsible for your care. The team consists of the doctor, PT and ATC.  During the pre-operative rehabilitation you will be instructed on walking as normally as possible, decreasing swelling in your knee, getting your knee to straighten out all the way and getting as much bend back in the knee as possible.

Your prescriptive therapy will:

  1. Decrease swelling
  2. Increase range of motion
  3. Improve gait so you walk without a limp
  4. Increase the strength in your leg
  5. Educate you on postoperative exercises
  6. Educate you on crutch walking

Your rehabilitation team will discuss these things with you and show you exercises that will help you get ready for surgery and make your post-operative therapy easier.

Pre-Operative Requirements:

Prior to your surgery, you may be instructed to perform a series of exercises in order to build up your strength and maintain normal motion. This will greatly help your recovery process after surgery.  Please perform all of the following exercises 1 to 2 times a day, 3 sets of 10 repetitions for each exercise.


Here are a few things we will want to see prior to going into surgery:

  • You must be able to demonstrate normal gait or walk without a limp. Some of you, however, due to the extent of your injury, will be instructed to stay on your crutches.
  • You must obtain at least 120 degrees of flexion or bend.These are the exercises you can perform to achieve this:


These exercises will help you stay strong:



Post-Operative Care:

After surgery you will be given a written instruction sheet, pictures of your surgery, a prescription for therapy and a copy of rehabilitation guidelines. This information will help answer most of the questions you may have during your recovery.  You will be going to physical therapy (PT) after your surgery.  At the initial evaluation you will meet the PT who, along with an Athletic Trainer (ATC), will be responsible for your rehabilitation.  During this visit, you will be instructed in Phase 1 exercises, wound care and how much weight you should place on your operated leg.  In addition, your therapist will ask you to help set your goals for rehabilitation.

If you have an ACL reconstruction, with no meniscal repair, you will be weight bearing when you are able to feel your leg again after surgery. If you have a meniscal repair, along with your ACL reconstruction, you will be on crutches longer as guided by your surgeon.

The entire rehabilitation process will take 5 to 6 months. During the early phase of your rehabilitation, you will be closely monitored.  As you progress, you will be able to do more exercises on your own.  If you have any questions concerning your rehabilitation process, they should be directed to your rehabilitation team.