Prateek Gupta

Prateek is currently a candidate for the Master of Physical Therapy from McGill University. He is excited to disseminate evidence-based information on rehabilitation and healthcare with Curovate.

Toronto 4 posts

Do knee braces work? What does the research say?

What is a knee brace?

Knee braces are external devices which can be soft or rigid and are prescribed by some healthcare providers after knee injury or surgery. In this blog I will focus on knee braces prescribed after an anterior cruciate ligament (ACL) surgery.

How is a knee brace used? Are there any issues with bracing?

Knee braces are recommended by some healthcare providers for one to two months after an Anterior Cruciate Ligament (ACL) surgery1. According to a survey done on American Orthopaedic surgeons, 63% report prescribing functional bracing after ACL surgery. Additionally, 71% of them prescribe these braces for up to 1 year after surgery2.

What are the different types of braces for the knee?

There are two kinds of braces used after ACL surgery:

  1. Functional knee braces - are worn after an ACL surgery to reduce improper knee movements such as excessive rotation, sliding side to side or front to back (translation) and the knee caving inwards.3 They are designed to substitute for damaged ligaments and are often prescribed for people who have torn their ACL and are not planning to get surgery.4

  2. Prophylactic knee braces - are designed to protect people from sustaining a knee injury without causing limitations in knee movement.5

What does research say?

Researchers found that people under the age of 30 experience muscle weakness with long term use of braces (1 to 2 years), compared to short term uses (3 months).6

Prophylactic Knee brace Functional Knee brace
1. There was no significant difference found among 31 healthy college athletes in single leg vertical jump, cross-over hop, and average power between wearing a prophylactic brace and not wearing a brace. Average power output was measured using isokinetic testing. Isokinetic testing involves a piece of equipment that allows the knee to be resistance tested while the person bends and straightens their knee at a specific speed. The speeds used were 60, 180 and 300 degrees per second.5 1. Researchers found a substantial reduction in quadriceps muscle (muscles at the front of your thigh) strength with long term use (1-2 years). There were no differences in the amount of knee movement (range of motion) and a persons awareness of their knee position (proprioception). Researchers did find wearing a brace improved knee stability by reducing excessive lower leg rotation and translation, as well as decreasing excessive knee bending or straightening. This study was a literature search of 15 research articles using PubMed and Embase databases to compare functional bracing to no bracing 3 months after ACL reconstruction.3
2. There are no significant differences in the amount of pressure and force on the knee between wearing a prophylactic brace or not. But wearing the brace significantly reduced rotation (inward and outward rotation) of the knee. For example, lower leg rotation reduced from 19.76 degrees to 15.91 degrees, when wearing the brace. Additionally, participants found that wearing the brace gave them a sense of stability while running. This study tested 20 female netball university athletes (20 years old) who were asked to do running, jumping and cutting movements on a force plate in a lab.7 2. 100 patients, all with a torn ACL, underwent a Bone-Patellar-Bone ACL reconstruction and were randomized into a braced and non-braced group. They were followed for 12 months. Patients in the unbraced group returned to work 1.84 months after surgery, compared to 2.28 months in the braced group. Additionally, 96% of the unbraced patients said they have no difficulty in climbing stairs compared to 93% of patients who used a functional brace.8

Do you need some more information and assistance after your ACL injury? Check out our ACL app!


  1. Hiemstra, L. A., Veale, K., & Sasyniuk, T. (2006). Knee immobilization in the immediate post-operative period following ACL reconstruction: A survey of practice patterns of canadian orthopedic surgeons. Clinical Journal of Sport Medicine, 16(3), 199-202.

  2. Marx, R. G., Jones, E. C., Angel, M., Wickiewicz, T. L., & Warren, R. F. (2003). Beliefs and attitudes of members of the american academy of orthopaedic surgeons regarding the treatment of anterior cruciate ligament injury. Arthroscopy: The Journal of Arthroscopic and Related Surgery, 19(7), 762-770

  3. Lowe, W. R., Warth, R. J., Davis, E. P., & Bailey, L. (2017). Functional bracing after anterior cruciate ligament reconstruction: A systematic review. Journal of the American Academy of Orthopaedic Surgeons, 25(3), 239-249.

  4. Cluet, J. (2017). Types of Knee Braces for Support and Injury Prevention. VeryWell.

  5. Mortaza, N., Ebrahimi, I., Ali, A. J., Abdollah, V., Kamali, M., Wan Abu Bakar, W. A., & Noor Azuan, A. O. (2012). The effects of a prophylactic knee brace and two neoprene knee sleeves on the performance of healthy athletes: A crossover randomized controlled trial. PLoS One, 7(11), e50110.

  6. Risberg, M. A., Beynnon, B. D., Peura, G. D., & Uh, B. S. (1999). Proprioception after anterior cruciate ligament reconstruction with and without bracing. Knee Surgery, Sports Traumatology, Arthroscopy, 7(5), 303-309.

  7. Sinclair, J. K., Vincent, H., & Richards, J. D. (2017). Effects of prophylactic knee bracing on knee joint kinetics and kinematics during netball specific movements. Physical Therapy in Sport, 23, 93-98.

  8. Nazem, K. A., Mehrbod, M., Borjian, A., & Sadeghian, H. (2006). Anterior cruciate ligament reconstruction with or without bracing.

ACL graft sites, what's the difference?

There are usually 2 areas where a surgeon can take a graft to replace your ACL. The two areas are your patellar tendon or your hamstring tendons. If this is new information to you, refer to our previous post on some details about ACL surgery here.
When reading the differences listed below it is important to remember that your surgeon will choose the graft site for your ACL surgery. The good news is that our app, Curovate, for ACL rehabilitation has a protocol for hamstring tendon or patellar tendon grafts here.

Hamstring Graft Surgery (HT) Patellar tendon also called Bone-Patellar-Bone Surgery (BTB)
1. The operation takes more time and the tourniquette, which is a device used during surgery to limit blood flow in the leg, is on for longer2 1. The knee is stiffer after surgery2
2. The knee moves more freely front and back, when tested using a KT-1000 Arthrometer machine2, which is a device that measures front and back movement of your lower leg compared to your thigh. 2. More knee pain when kneeling on the ground3
3. Over a period of 15 years after surgery there were more reinjuries reported.3 3. Over a period of 15 years after surgery more stiffness and difficulty straightening the knee was reported3.
4. The need to do another surgery to address issues with the first surgery is called a revision surgery. The revision rates, for hamstring graft surgeries increases by 0.65% within 1 year and by 4.45% within 5 years4. 4. Revision rate after 1 year is 0.16% and revision rate after 5 years is 3.03% for patellar tendon graft surgeries4.
5. Hamstring muscle power reduced by 15%1. Muscle power is the maximum force you can apply in as short a time as possible.
6. Muscle strength reduces by 11% when straightening the knee2. Muscle strength is how much force a muscle can produce in a maximal effort.
7. There is more instability in the knee when force is applied2. Instability is undesirable movement in a joint.


I injured my ACL what should I do?

You can either manage your ACL injury surgically or non-surgically. Which form of treatment is right for you is determined by you and your health care provider.

Surgical treatment

Autograft and Allograft Surgery1,2,3,4
1. Autograft surgery means taking a tendon or a ligament from another part of your body, also called a graft, and replacing the injured ACL.
2. Allograft surgery is when a piece of ligament or tendon is taken from a cadaver, a deceased body, and used to replace the injured ACL.

In this post we will focus on the autograft surgery. There are two areas where the graft is taken from. The surgeon chooses the graft site for your ACL surgery (also called an ACL reconstruction).

a) Bone-Patellar Tendon-Bone Reconstruction (BTB)

  • The patella is the small bone that you can touch in front of your knee and the patellar tendon sits below this bone
  • The patellar tendon is an extension of the 4 upper thigh muscles called the quadriceps, which allow the knee to straighten
  • During this surgery, a piece of the patellar tendon is removed and used to replace the ACL5

b) Hamstring Tendon Reconstruction (HT)

  • The hamstrings are a group of three muscles (Semitendinosus, Semimembranosus, and Biceps Femoris) that are located on the back of your thigh.
  • They allow you to bend your knee and bring your hip back
  • During the Hamstring Tendon Reconstruction surgery, part of the Semitendinosus and Gracilis tendons are used to replace the injured ACL5

Prior to surgery it is essential to rehabilitate the knee to make sure you are ready for surgery. After surgery you will need at least 6 to 8 months of rehabilitation to return to your prior level of physical activity and sports. This rehabilitation is typically guided by a Physical Therapist but you will have to do at least 60 to 90 minutes of exercises daily. There is a huge time commitment to rehabilitation exercises after ACL reconstruction. Curovate offers a pre and post-operative app which has 6 months of video guided exercises to help you with your ACL recovery.

Non-surgical treatment

Progressive Physical Therapy is crucial for the treatment of ACL injuries. Weekly exercises are provided that will reduce knee pain, increase knee mobility, return to normal walking, and eventually return to running and jumping. How much you will be able to do after the injury is based on your particular injury, your knee health before and after the injury and what you and your Physical Therapist decide is appropriate for you. There will be more information on non-surgical management in a future blog post. Stay tuned!
Curovate has a non-operative version of their app which provides video guided exercises and progress tracking to help you recover from your ACL injury.


What is an ACL and how is it injured?

  • Anterior Cruciate Ligament (ACL) is one of the four ligaments in the knee joint
  • The ACL runs diagonally inside the knee like a rope to make the joint stable.
  • The ACL keeps the knee stable when changing directions quickly or when landing from a jump1

How is the ligament injured?

  • Changing direction with the knee caving in
  • Planting and twisting with your foot planted
  • Stopping suddenly on a straight knee
  • Landing from a jump with the knees caving in
  • Being hit on the knee from the front or the side

Young female athletes are more likely to tear their ACL compared to male athletes2