June 10, 2022

A Guide to Physical Therapy for an ACL Tear

If you have suffered an ACL tear, you may be wondering what your next steps should be. You may be feeling a range of emotions, from confusion and frustration to optimism. One thing is for sure: you are not alone.

The ACL is the most commonly injured ligament in the knee, with an estimated 200,000 Americans suffering an ACL tear each year. Of these cases, only about 30% of them are from a contact sport.1

The good news is that most people who suffer an ACL tear can make a full recovery with the help of physical therapy. This comprehensive guide to physical therapy for ACL tears discusses symptoms, causes, diagnosis, treatment, and prevention tips.

Table of Contents

Understanding an ACL Tear

The anterior cruciate ligament, or ACL, is a key ligament in the knee for stabilizing the joint. It connects the femur (thigh bone) to the tibia (shin bone). The ACL prevents the shin bone from sliding forward excessively on the thigh bone and also provides rotational stability to the knee.

ACL tears are a relatively common injury, particularly among athletes who participate in sports that involve cutting or pivoting movements (such as soccer, basketball, and skiing). However, anyone can tear their ACL.

ACL tears can range from partial to complete. A complete tear is when the ligament has been completely torn or ruptured. A partial tear is when the ligament has been partially damaged but is still attached to the bone.

Symptoms of an ACL Tear

An ACL tear is often initiated with a sudden sharp pain that might be accompanied by a loud pop or popping sensation. Other symptoms can include:

  • Swelling
  • Instability in the knee joint
  • Inability to put weight on the affected leg
  • Feeling like the knee is going to give out
  • A sensation that the knee is "locking" or "catching"

Causes of an ACL Tear

There are a number of different actions that can lead to an ACL tear, including:

  • Landing awkwardly from a jump, particularly if the knee is straight or in a valgus position (the knees are too close together)
  • Changing direction quickly (cutting)
  • Slowing down when running, but keeping the foot planted
  • Direct contact or collision, such as a tackle in football
  • Twisting the knee while the foot is firmly planted

Additionally, there are risk factors that can increase the likelihood of a tear:2

  • Previous ACL injury
  • Being female (due to anatomical differences and potential tissue laxity)
  • Participating in high-risk activities, such as football, soccer, and basketball
  • Altered knee biomechanics due to knee pain, hip weakness, core weakness, etc.
  • Poor joint alignment due to structural anomalies, altered foot alignment, and changes in hip or core mechanics
  • Friction levels between shoe wear and the ground (i.e. turf or rubber rice in different weather conditions)

Diagnosing an ACL Tear

If you suspect you have torn your ACL, it is important to see a doctor or orthopedic surgeon as soon as possible. They will perform a physical examination and will likely order imaging tests, such as an MRI (the gold standard for the knee), to confirm the diagnosis and assess other potential knee damage that is common with an ACL tear (other ligaments, menisci, etc.).

Once the degree of your injury has been assessed, it's time to work with a movement expert. Your CityPT physical therapist will diagnose your functional deficits caused by the ACL tear by looking at key factors like range of motion, flexibility, strength, and coordination. Once a thorough assessment has been completed, they can help you design a comprehensive recovery plan.

Can I Recover from an ACL Tear without Surgery?

There is no definitive answer to this question, as it depends on a lot of factors. It is estimated that 50% of patients with an ACL tear will need surgery.3 Ultimately, what is best for your knee recovery will depend on your specific injury, other health factors, and your activity goals.

However, research does show that some knees respond well to conservative treatment without the need for more invasive options, especially for those that exhibit fewer signs of instability.4

Factors that might make you a candidate for recovery without surgery include:5

  • Living a sedentary lifestyle
  • Being over the age of 40
  • Lack of gross instability in the knee with daily activities
  • A great initial response to conservative rehab (in the first 4 to 6 weeks)

What if I Need Surgery for My ACL Tear?

With the right physical therapy rehabilitation program, most people are able to return to their previous level of activity (or even improve upon it!). The latest research supports initiating physical therapy as soon as possible post-surgically (and pre-surgically if there will be a delay) to enhance your knee function and outcomes.2

Physical Therapy for an ACL Tear: What to Expect

Regardless of whether surgery is needed or not, the first few weeks of rehab are typically focused on protecting the knee and allowing the tissues time to heal. When the knee is ready, your physical therapist will guide you in initiating knee range of motion and strengthening exercises. Finding the right balance between rest and motion is key for maximizing the recovery period.

As you progress in your physical therapy, the focus will shift to rebuilding strength, control, and confidence in your leg. This will require a combination of exercises that challenge your proprioception (joint position sense), single-leg balance, and core stability.

A typical ACL physical therapy program will progress through the following stages:2

  • Stage One: Protecting the knee and allowing tissues to heal (0-12 weeks)
  • Stage Two: Regaining motion and rebuilding strength (12-24 weeks)
  • Stage Three: Return to sports training (or daily activities) (after 24 weeks)

It is important to note that each individual will progress through these stages at a different rate. Overall, the goal with CityPT physical therapy is to help you safely and effectively return to your desired level of activity.

Preventing an ACL Tear

There are several things you can do to help prevent an ACL tear or other knee injuries. Here are a few key tips:

  • Warm up and cool down properly before and after physical activity
  • Maintain good flexibility in your hips, hamstrings, and quadriceps
  • Strengthen your thigh and core muscles, most importantly including the hips, quads, and hamstrings in a weekly exercise program
  • Use proper technique when participating in sports or other activities, particularly taking care to prevent a "knock knee" position with jumping
  • For athletes, participate in a research-based exercise program specifically for your sport to help you focus on optimal form with common sport-specific moves6
  • Modify or avoid high-risk activities (such as downhill skiing) if you have a previous knee injury (if feasible)
  • Wear shoes that support your feet and ankles and have an appropriate level of friction for the activity you are participating in
  • Be mindful of training volume, start slowly and progress gradually to reduce the risk of knee injury associated with muscle fatigue
  • Limited research supports the use of a knee brace if you have sustained a previous injury7
  • Practice healthy habits that ensure optimal tissue health, such as good sleep, nutrition, and stress management

When to Start Rehab for an ACL Tear

Sustaining an ACL tear can quickly change the mechanics of your leg and lead to instability in the knee joint. It is important to seek out professional help as soon as possible to ensure you are on the path to full recovery and reduce the risk of long-term complications like arthritis. Ultimately, having a movement expert by your side will help you feel confident in your leg as you navigate healing and a return to your normal activity levels.

Book an appointment with one of our CityPT orthopedic specialists today to get started.

This guide is intended for informational purposes only. We are not providing legal or medical advice and this guide does not create a provider-patient relationship. Do not rely upon this guide (or any guide) for medical information. Always seek the help of a qualified medical professional who has assessed you and understands your condition.



  1. Evans J, Nielson Jl. Anterior Cruciate Ligament Knee Injuries. [Updated 2022 May 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. https://www.ncbi.nlm.nih.gov/books/NBK499848/

  2. Physiopedia. Anterior Cruciate Ligament (ACL) Injury. Physiopedia.com. Accessed August 31, 2022. https://www.physio-pedia.com/Anterior_Cruciate_Ligament_(ACL)_Injury 2 3

  3. Dhillon KS. "'Doc' do I need an anterior cruciate ligament reconstruction? What happens if I do not reconstruct the cruciate ligament?". Malays Orthop J. 2014 Nov;8(3):42-7. doi: 10.5704/MOJ.1411.010. PMID: 26401236; PMCID: PMC4536400.

  4. Konrads C, Reppenhagen S, Belder D, Goebel S, Rudert M, Barthel T. Long-term outcome of anterior cruciate ligament tear without reconstruction: a longitudinal prospective study. Int Orthop. 2016 Nov;40(11):2325-2330.

  5. Mall NA, Frank RM, Saltzman BM, Cole BJ, Bach BR Jr. Results After Anterior Cruciate Ligament Reconstruction in Patients Older Than 40 Years: How Do They Compare With Younger Patients? A Systematic Review and Comparison With Younger Populations. Sports Health. 2016 Mar-Apr;8(2):177-81.

  6. Sugimoto D, Myer GD, Bush HM, Klugman MF, McKeon JM, Hewett TE. Compliance with neuromuscular training and anterior cruciate ligament injury risk reduction in female athletes: a meta-analysis. Journal of athletic training. 2012;47(6):714-23.

  7. McDevitt ER, Taylor DC, Miller MD, Gerber JP, Ziemke G, Hinkin D, Uhorchak JM, Arciero RA, Pierre PS. Functional bracing after anterior cruciate ligament reconstruction: a prospective, randomized, multicenter study. Am J Sports Med. 2004 Dec;32(8):1887-92. doi: 10.1177/0363546504265998. PMID: 15572317.

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