Learn about treatment options
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What does the ACL do?
The knee has a ligament called the anterior cruciate ligament (ACL), which connects the thigh bone (femur) to the shin bone (tibia). This ligament helps to stabilise the knee, and stops the knee joint surfaces from sliding, gliding and rotating.
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If you tear your ACL, your knee may feel unstable, painful and swollen.
The goals of treatment are to restore knee stability, improve muscle strength and function, and help you safely return to sports and other activities.
Can my ACL heal without surgery?
People used to think that the ACL could not heal without surgery, but new research suggests that healing is possible.
A recent study found that if people try rehab before considering surgery, at least one in three people experience some healing of their ruptured ACL. Half of these people achieved an ACL heal that looked like a normal ACL on MRI 2 years after a full rupture, and the other half had a thinner or longer ACL than normal, despite the ACL fibres reconnecting (1). ACL healing can be assessed on MRI as early as 3 months after ACL rupture, and in many cases, ACL healing will continue to improve over time (2).
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The Cross Bracing Protocol
Scientists are now testing treatments to help more people heal their ACL naturally without surgery. A new treatment option that is being tested is the Cross Bracing Protocol, which involves wearing a knee brace with the knee initially held in a bent position to assist with healing. Early findings are promising, with around 90% of people achieving some degree of healing after 12 weeks of knee bracing (3).
There is now a clinical trial underway to compare outcomes between two treatments, the Cross Bracing Protocol and ACL surgery. If you have recently ruptured your ACL, are aged between 16-40 years, and live in Australia, you may be able to take part in this study. Visit www.embracestudy.com.au for more information.
Treatment options for an ACL injury
If you have an ACL tear, there are surgical and non-surgical treatment options supported by research:
ACL reconstruction surgery
An ACL reconstruction is performed under a general anaesthetic. Incisions are made at the front of the knee with a surgical blade to allow access to the knee joint.
The surgeon will insert a small camera, probe, drill, screwdriver and other tools through the incision to perform the procedure. The surgeon will remove the torn ACL from the bone, and drill tunnels into the thigh bone (femur) and shin bone (tibia). The ACL graft is placed into the tunnels and held in place by screws. The screws will secure the ACL graft (tissue taken from elsewhere in the body to replace the ACL) to the thigh and shin bones.
You will most likely spend the night in hospital.
If you would like to see a video demonstration of ACL surgery, you can watch this here: ACL Reconstruction Surgery (video courtesy of National University Hospital (NUH), Singapore)
An ACL graft is a piece of healthy tissue taken from somewhere else in the body that is used to replace the torn ACL. The most common ACL graft used is a piece of tendon taken from your thigh (hamstring), or the middle third of the tendon below the knee cap (and attaching bone either side). More incisions may be required to remove this tissue.
After surgery, most people feel pain and are given painkillers. The knee will be swollen and moving may cause discomfort.
Moving the knee in walking is very important in this early stage to increase your ability to bend and straighten your knee and to work towards walking normally. You are likely to need crutches to move around for the first two weeks, and you should not drive for between two to six weeks. Your surgeon will tell you when it's safe to drive again, depending on which knee was operated on and the type of car you drive.
Depending on your job or studies, you may need to take time off. Desk-based jobs may require a two-week break, while manual labour may need a few months off.
After surgery, you will spend one to two months focusing on managing pain, reducing swelling, strengthening your thigh muscles, and improving your ability to bend and straighten your knee.
After surgery, you will start rehab. Initial rehab after surgery will focus on managing pain, reducing swelling, improving movement and working to switch on the muscles around your knee. As your pain and swelling improves, it is recommended to consult a physiotherapist to guide you through a structured rehab plan, with key goals for each phase. The speed at which people progress through rehab varies according to when they achieve certain rehab goals.
Rehab typically lasts around 12 months after ACL surgery but can be a little shorter or longer for some people.
Scroll down to the section ‘Rehab after an ACL injury’ to see a video that will give you an idea of the types of exercises that might be included in an ACL injury rehab program.
Rehabilitation without surgery
Rehabilitation can start straight after an ACL injury. Depending on the nature of an ACL injury, some people choose to combine rehabilitation with knee bracing in attempt to assist with healing their ACL rupture. It is recommended that you consult a physiotherapist to guide you through a structured rehabilitation plan, with key goals for each phase.
Non-surgical rehabilitation is very similar to the rehabilitation performed after ACL surgery, and uses the same goals to determine the speed someone progresses through the different phases of rehabilitation. However, rehabilitation without surgery typically progresses at a faster rate than rehabilitation after surgery, as you don’t need to account for the post-operative pain, swelling and difficulty contracting your muscles that occurs with surgery.
The principles of ACL rehabilitation are similar for those who undergo an ACL reconstruction and those who undergo non-surgical management.
Rehab after an ACL injury
As the section above details, the principles of ACL rehab are similar for those who have an ACL reconstruction and those who choose non-surgical management. The video to the left will give you an idea of the types of exercise that might be included in an ACL injury rehab program.
Your physiotherapist will guide you through an individualised, goal-based rehab.
The earlier phases of rehab will focus on:
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Managing pain and knee swelling (this is more relevant for people who have surgery)
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Achieving full knee range of movement, and
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Strengthening the muscles around the knee
The next phase will include harder strengthening exercises, as well as exercises that focus on movement, control and balance. Your physiotherapist will usually test your knee function (for example, using hop tests and strength tests) to determine when to progress to the next phase of rehab.
Later phases of ACL rehab will be tailored to your specific activity and sporting goals. Your exercise program is now likely to include agility drills, plyometric exercises and sport-specific tasks.
Your physiotherapist will conduct further tests of your knee throughout rehab to determine if you are ready to return to running, jumping, pivoting and competitive sports. Of those who return to sport, most do so 12-18 months after surgery/injury, but everyone’s recovery is different. You should continue to complete some knee exercises, even if you have returned to your chosen sport or activity, to help reduce the risk of another knee injury.
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If you have gone through at least three months of rehab and still don't feel satisfied with your knee function and stability, ACL surgery may be a good option to consider.
Postponing the decision to have surgery does not result in worse outcomes compared to having surgery right after the injury (1).
Research suggests that performing rehab for 1 to 6 months before surgery improves knee strength and function after surgery (4-6).
Two clinical trials conducted in Europe have shown that around 50% of people who start rehab with the option of having surgery later on, decided to have ACL surgery within two years.
These people included those who had a strong preference for surgery before the studies, and those who decided to enrol into the study so that they could bypass the waitlist for surgery (7-9).
On the other hand, 50% of people in these trials were satisfied with the outcome of rehab without surgery.
What if I want surgery after trying rehab?
When deciding whether to have ACL surgery, considering rehab first is appropriate for most people. A recent review (9) and consensus statement (10) support this approach.
However, there are certain cases where surgery may be recommended. For example, if the knee is still unstable after trying rehab (11). Those with severe injury to other knee structures may also need ACL surgery, although there is limited evidence to support this.
A healthcare professional should be able to discuss with you if surgery may be recommended in your case.
Is trying rehab first recommended?
Treatment pathways
The graphic below shows possible treatment pathways following ACL injury. In Step 3 and Step 4 of this decision aid we will explore outcomes of these different pathways in more detail.
ACL injury
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Treatment decision
Surgery
Rehab without surgery
Dissatisfied with outcome
Satisfied with outcome
Satisfied with outcome
Dissatisfied with outcome
Post-surgical rehab
1. Filbay, S.R., Roemer, F.W., Lohmander, L.S., Turkiewicz, A., Roos., E.M., Frobell, R., & Englund, M. (2023). Evidence of ACL healing on MRI following ACL rupture treated with rehab alone may be associated with better patient-reported outcomes: a secondary analysis from the KANON trial. British Journal of Sports Medicine, 57, 91-99, https://doi:10.1136/bjsports-2022-105473
2. Kvist., J., Liu, A., Giannoti, N., Filbay, S., Hedevik, H., Stalman, A., Frobell, R., Gauffin, H., & Englund, M. (2025). Structural changes of the anterior cruciate ligament (ACL) evaluated by MRI, and their relation to clinical outcomes, under two years after ACL injury. Results from the pragmatic NACOX-cohort study. JOSPT. In Print, Jan 2026
3. Filbay, S.R., Dowsett, M., Chaker Jomaa, M., Rooney, J., Sabharwal, R., Lucas, P., Van Den Heever, A., Kazagalis, J., Merlino, J., Moran, M., Allwright, M., Kuah, D.E.K., Durie, R., Roger, G., Cross., M. & Cross, T. (2023). Healing of acute anterior cruciate ligament rupture on MRI and outcomes following non-surgical management with the Cross Bracing Protocol. British Journal of Sports Medicine, 57(23), 1490-1497, https://doi:10.1136/bjsports-2023-106931
4. Giesche, F., Niederer, D., Banzer, W., & Vogt, L. (2020). Evidence for the effects of prehabilitation before ACL reconstruction on return to sport-related and self-reported knee function: A systematic review [Review]. PLoS ONE, 15(10 October), Article e0240192, https://doi.org/10.1371/journal.pone.0240192
5. Carter, H. M., Littlewood, C., Webster, K. E., & Smith, B. E. (2020). The effectiveness of preoperative rehabilitation programmes on postoperative outcomes following anterior cruciate ligament (ACL) reconstruction: A systematic review [Review]. BMC Musculoskeletal Disorders, 21(1), Article 647. https://doi:10.1186/s12891-020- 03676-6
6. Alshewaier, S., Yeowell, G., & Fatoye, F. (2017). The effectiveness of pre-operative exercise physiotherapy rehabilitation on the outcomes of treatment following anterior cruciate ligament injury: A systematic review. Clinical Rehabilitation, 31(1), 34-44. https://doi:10.1177/0269215516628617
7. Frobell RB, Roos EM, Roos HP, et al. A Randomized Trial of Treatment for Acute Anterior Cruciate Ligament Tears. New England Journal of Medicine 2010;363(4):331-42, https://doi:10.1056/NEJMoa0907797
8. Reijman M, Eggerding V, Es Ev, et al. Early surgical reconstruction versus rehabilitation with elective delayed reconstruction for patients with anterior cruciate ligament rupture: COMPARE randomised controlled trial. BMJ 2021;372-375, https://doi:10.1136/bmj.n375
9. Saueressig T, Braun T, Steglich N, et al. Primary surgery versus primary rehabilitation for treating anterior cruciate ligament injuries: a living systematic review and meta-analysis. British Journal of Sports Medicine 2022;56(21):1241- 51, https://doi:10.1136/bjsports-2021-105359
10. Whittaker JL, Culvenor AG, Juhl CB, et al. OPTIKNEE 2022: consensus recommendations to optimise knee health after traumatic knee injury to prevent osteoarthritis. British Journal of Sports Medicine 2022;56(24):1393-405, https://doi:10.1136/bjsports-2022-106299
11. Beard DJ, Davies L, Cook JA, et al. Rehabilitation versus surgical reconstruction for non-acute anterior cruciate ligament injury (ACL SNNAP): a pragmatic randomised controlled trial. Lancet 2022;400(10352):605-15, https://doi:10.1016/s0140-6736(22)01424-6