ACL Tear Injury - Answers to Your Questions

ACL Tear Injury - Answers to Your Questions

What is the ACL?

The Anterior Cruciate Ligament (ACL) is a ligament in your knee connecting your femur (thigh bone) to your tibia (shin bone). It is important for keeping your knee joint stable and for preventing excess twisting or rotation of your knee.  

How do you tear your ACL?

ACL tears most often occur when the foot is fixed to the ground, the knee is a knock-kneed position and the body rotates over the foot. With enough force, the combination of these movements and positions can cause the ligament to tear.

Can you still walk with a torn ACL?

After a tear there will be significant pain and swelling. Severity of symptoms can be different for each person and a Physiotherapist will be able to determine if walking is possible. Most often you’ll be able to walk in a straight line but you may find it difficult to make sudden turns. After the swelling and initial pain has subsided most can walk normally again even though their ACL is still torn.

Depending on the degree of your ACL tear, an ACL brace can help you walk by stabilizing the knee. 

Common Examples of Brace Use of courtesy of PhysioPlus Health Group (Read the caption):

What are the signs of an ACL tear?

An ACL tear often happens in dynamic sports like basketball, soccer, and football. A strong indicator of an ACL tear is the presence of snapping or popping sounds when the injury occurs. The reason this sound occurs is because the ligament is very strong, thus creating a loud snap when it tears.  Also, ACL tears usually cause immediate swelling after impact. 

Once acute pain and swelling reduces, extending the knee and pivoting on the knee are common signs of a tear.

How long does an ACL injury take to heal?

If you do not have surgery, conservative management usually takes 3-6 months. If you choose to undergo surgery, it can take 9 months to a year. Your surgeon and physiotherapist will determine when it is appropriate for you to return to your sport. They will make their decision based on knee stability, mobility, and strength, your performance on functional knee tests and your own feelings on your readiness for return to sport.

How do I know if I need surgery?

Determining whether to undergo surgery or not is a very difficulty decision after sustaining an ACL injury. There are many factors that you, your surgeon and your physiotherapist will take into consideration when making this decision. First, is how large your ACL tear is. It is more common to undergo surgery for complete ruptures compared to partial tears. Another consideration is the sport that you will be returning to. If you are returning to sports that require pivoting on the knee such as soccer, basketball or downhill skiing, you may get better outcomes with ACL surgery. However, if you want to return to less dynamic sports such as running or cycling, you may do well with conservative management. 

If surgery is chosen, your physiotherapist may encourage you to complete “Prehab”. This involves completing exercises to improve your knee mobility and strength a few weeks-months prior to surgery. Research has shown that completing prehab enhances post-surgery outcomes!

If conservative management is chosen, you will complete a Physiotherapy program to improve knee strength and function. If, after a complete rehab program, your knee is still not stable enough to return to regular activities you may require ACL surgery.

It is important to note that many people successfully rehab their knee with a physiotherapy program after sustaining an ACL tear.

Can an ACL heal on its own?

If it’s a complete tear, ACL’s usually do not health themselves as there is no blood supply to this ligament.

Knee Injury – Torn ACL or MCL courtesy of BeActive Physiotherapy and Wellness

How do you tell if the ACL is torn or sprained?

The most accurate way to tell is with an MRI scan of your knee. However, it’s not always possible to get a quick MRI. So seeing a physiotherapist will be helpful as they can use multiple tests to determine the presence of a tear. These tests are called the Lachman’s test, the Anterior Drawer test, the Lever test and the pivot shift test. 

To complete a Lachman’s test, your physiotherapist will first stabilize the thigh and have the patient relax the leg. They will then grab your tibia which is right below the knee and pull upwards. If your ACL is torn there will be excess motion and it may be painful.

The Anterior Drawer is very similar to Lachman’s test, however it is completed with a bent knee compared to a straight knee.

The Lever test, is a newer maneuver that physiotherapist’s are using to detect ACL tears. This involves the patient lying on their back, and the therapist starting with placing one of their fists under the calf of the patient. The therapist will then use their other hand to push down on the lower thigh of the patient. If the heel of the patient lifts off from the table, it means the ligament is intact. If the heel does not lift, it may indicate an ACL tear. 

The Pivot Shift Test is sometimes difficult to do when the athlete’s knee is sore. To complete the test, a Physio will take the heel of the foot and lift the leg up while extended. They will then rotate the leg inwards. Next they will take the knee from full extension to 90 degrees bent.  If there is an ACL tear it will produce a clunking or the feeling that the patient felt when they tore their ACL.

Is ACL recovery painful?

The first couple of weeks after surgery will be the most painful. As rehab progresses, the pain will subside. In the early stages of recovery, you can manage the pain with icing and by keeping your knee elevated. Also, your doctor may prescribe you pain medication.

How long will my knee hurt after surgery?

You can have pain in the front of your knee for about 1-2 months after surgery. It may persist longer depending on how your rehab is going.

What happens if a torn ACL goes untreated?

If your torn ACL goes untreated, you may experience persistent instability in your knee as the ligament is a major stabilizer of the joint. This may lead to pain and even may cause early-onset osteoarthritis. 

Concerned about ACL symptoms? Book an appointment with one of our Physiotherapists by using the search box on this page to find one near you.

Knee Anatomy Facts courtesy of Clearwater Physical Therapy (Read the caption)


This appointment is your opportunity to tell us what hurts and discover whether physiotherapy or chiropractic care is a good fit for you! During this session, you will talk with a physiotherapist or chiropractor on a phone call (or online) and create the right care plan specifically for your pain. There is no obligation on this session is to find out whether physiotherapy or chiropractic care can help you getting back to doing the things you love in life.

About Taylor Sipos

Taylor is a physiotherapist at The Orthopaedic Therapy Clinic located in Toronto, Ontario. He treats patients with various musculoskeletal conditions using patient education, exercise therapy, manual therapy and acupuncture. His treatment philosophy involves giving his patient’s the means to self-manage their injuries. He does this through reassurance, education and health promotion. Taylor uses the same principles as a patient educator at Pain Hero. He aims to provide you with high-quality, easy to understand information to teach you about your condition and how to improve it.

Medical Disclaimer:

The information presented in this blog post is for educational purposes and should not be interpreted as medical advice. If you are seeking medical advice, treatment or a diagnosis, consult with a medical professional such as one suggested on this website. The Clinic Accelerator Inc. and the author of this page are not liable for the associated risks of using or acting upon the information contained in this article.

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