Reviewed by Dr Vishal Pai
An ACL reconstruction replaces a torn anterior cruciate ligament (ACL) with a graft to make an unstable knee more stable. It is the standard type of ACL surgery, while ACL repair suits only some tears. This page covers what the operation involves, what recovery looks like and when you can return to sport.
At a Glance
- ACL reconstruction replaces the torn ligament with a graft, usually from your own hamstring or quadriceps tendon.
- Not everyone needs surgery. If you don’t play pivoting sports, physiotherapy-led rehabilitation may be enough.
- Recovery takes months. Getting your knee fully straight is the key early goal, and most people stop using crutches within 2–3 weeks.
- Dr Vishal Pai recommends waiting at least 12 months, and passing return-to-play testing, before you return to competitive sport.
What is an ACL reconstruction?
An anterior cruciate ligament (ACL) tear or rupture can lead to symptoms of knee instability. If the knee keeps giving way, it can damage the menisci (the cartilage cushions in the knee) and may lead to earlier arthritis. An ACL reconstruction uses a graft to replace the torn ligament, with the aim of improving the stability of your knee.
Dr Vishal Pai also performs ACL reconstruction in children and teenagers. You can read how it differs from adult surgery on the paediatric ACL reconstruction page.
Who might need an ACL reconstruction?
An ACL reconstruction is most often recommended for young, active people who want to return to sports that involve pivoting, cutting or jumping, and for people whose knee keeps giving way despite physiotherapy. It is also often recommended when there is a repairable meniscal tear. Not everyone with a torn ACL needs surgery.
What is involved in an ACL reconstruction?
The steps involved in anterior cruciate ligament reconstruction surgery include:
1. Knee arthroscopy
Keyhole surgery is performed to confirm the ACL tear and identify secondary injury to the cartilage and meniscus. Any secondary injuries are treated during the same procedure.
2. Graft harvest
A graft is harvested, prepared, and used to replace the torn ACL. This can be the hamstring tendons, patellar tendon, or quadriceps tendon. The choice of graft is discussed between you and Dr Vishal Pai during your consultation and depends upon your sporting and work demands. For a majority of patients, a hamstring or quadriceps graft is a suitable choice.
3. Tunnel drilling
Bone tunnels are created within the femur and tibia in a location that simulates ACL origin and insertion. The tunnels are required to allow passage of the graft. An accurate bone tunnel is important so favourable forces can pass through the ACL graft. An improper tunnel position can cause early re-rupture of the graft and is a common technical cause of graft failure.
4. Graft passage and fixation
The graft is passed through the bone tunnels and fixed into place with screws or over a loop of strong sutures threaded to a button.
5. Lateral extra-articular procedure (LEAP)
A LEAP (lateral extra-articular procedure) is considered in patients at higher risk of re-injury following ACL reconstruction. This typically includes young athletes, those undergoing revision surgery, individuals with knee hyperextension, and patients demonstrating significant rotational instability on clinical examination.
The procedure acts as a safety belt, providing additional restraint during pivoting and cutting movements, thereby reducing stress on the ACL graft. There are two forms of LEAP: a lateral tenodesis and an anterolateral ligament reconstruction.
The aim of a LEAP is to improve rotational stability and lower the risk of the ACL graft failing in people at higher risk of re-injury.
Read more about a LEAP procedure and its benefits in ACL reconstruction surgery.
How long does it take to recover from an ACL reconstruction?
Recovery from an ACL reconstruction is measured in months, not weeks. Rehabilitation is criteria-based: you move to the next stage when your knee is ready, not on a fixed date. [1] Dr Vishal Pai recommends rehabilitation based on the Melbourne ACL Rehabilitation Guide 2.0, which moves you through each stage when your knee meets set goals. How quickly you progress depends on your knee and on how consistently you do your rehabilitation, so it varies from person to person.
As a rough guide:
- First few weeksGetting your knee fully straight is the most important goal. Bending usually comes back more easily.
- 2–3 weeksMost people are able to stop using crutches.
- 8 weeksBy this stage, Dr Vishal Pai expects your knee to straighten fully and to bend beyond 90 degrees.
- 3–4 monthsYou can start gentle straight-line jogging if your gym-based strength training is going well.
- 12 months or laterYou can return to competitive sport once you have passed return-to-sport testing.
Getting the knee straight early matters. A knee that isn’t straight by about 4 weeks is more likely to stay stiff, and some loss of straightening is one of the most common problems after this surgery. [2] [3] Running often begins at around 12-16 weeks, but your strength, swelling and pain should guide it, not the date alone. [4]
Swelling can last 3–6 months, and the knee can keep improving for 12–18 months.
For a stage-by-stage guide to what to expect after surgery, read ACL reconstruction recovery week by week.
If you would like to talk through what recovery could look like for you, you can book a consultation with Dr Vishal Pai.
What results can you expect?
Most people get back to some sport after an ACL reconstruction. About 8 in 10 return to some form of sport, about 2 in 3 get back to the level they played at before, and just over half return to competitive sport. [5]
The main setback is another ACL injury. About 3 in 100 people tear the graft again. [6] The risk is higher if you are young and go back to pivoting sports such as football, netball and basketball. Nearly 1 in 4 people under 25 who return to sport have a second ACL injury, in either knee. [7] Passing return-to-sport testing lowers the risk of tearing the graft, but it doesn’t remove it, and it doesn’t protect your other knee. [8]
If you are young and at higher risk of re-injury, adding a LEAP can lower the chance of the graft tearing, from about 11 in 100 to about 4 in 100 over the first 2 years. [9]
What are the risks and complications?
Every operation carries risks, and Dr Vishal Pai goes through them with you before you decide. The main risks of an ACL reconstruction are:
- Infection, in about 1 in 1,000 people when the graft is soaked in antibiotic [10]
- Blood clots in the leg, in about 1 in 200 people [11]
- Stiffness or difficulty getting the knee fully straight, which occasionally needs a further procedure [3]
- Tearing the graft again (see above)
- A numb patch on the inside of the leg after a hamstring graft, which usually improves with time
- Pain or weakness where the graft was taken, which usually settles
- Bleeding into the knee, which occasionally needs a return to theatre to wash it out
- Rarely, a break in the kneecap, if the graft is taken with a small block of kneecap bone (a patellar tendon graft, or sometimes a quadriceps graft)
Some people don’t return to their previous level of sport, and the risk of arthritis later in life is higher than for people who have never injured their knee. You will receive a written information sheet with the full list of risks.
Can I have ACL surgery without private health insurance?
ACL reconstruction may be available as a self-funded procedure. If surgery is recommended, our team can provide a detailed cost estimate and discuss all available treatment pathways.
Information sheet · PDF
Self-Funded ACL Surgery Cost Information Sheet
Download our cost information sheet to read at home or share with your family.
Where does Dr Vishal Pai consult and operate?
Dr Vishal Pai consults at Sandringham Orthopaedic Specialists, Suite 1, 60 Bay Road, Sandringham. He performs ACL reconstructions at Calvary Holmesglen Private Hospital, 490 South Road, Moorabbin, and The Avenue Hospital, 40 The Avenue, Windsor. Patients come from across Bayside, Glen Eira and the Mornington Peninsula, and some travel from regional Victoria.
References
Show all 16 referencesHide references
- van Melick N et al. 2016. Evidence-based clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus. British Journal of Sports Medicine.
- Noll S et al. 2015. Knee extension range of motion at 4 weeks is related to knee extension loss at 12 weeks after anterior cruciate ligament reconstruction. Orthopaedic Journal of Sports Medicine.
- Scholes C et al. 2023. Persistent knee extension deficits are common after anterior cruciate ligament reconstruction: a systematic review and meta-analysis of randomised controlled trials. Knee Surgery, Sports Traumatology, Arthroscopy.
- Rambaud AJM et al. 2018. Criteria for return to running after anterior cruciate ligament reconstruction: a scoping review. British Journal of Sports Medicine.
- Ardern CL et al. 2014. Fifty-five per cent return to competitive sport following anterior cruciate ligament reconstruction surgery: an updated systematic review and meta-analysis including aspects of physical functioning and contextual factors. British Journal of Sports Medicine.
- Turk RD et al. 2022. Critical criteria recommendations: return to sport after ACL reconstruction requires evaluation of time after surgery of 8 months, >2 functional tests, psychological readiness, and quadriceps/hamstring strength. Arthroscopy.
- Wiggins AJ et al. 2016. Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: a systematic review and meta-analysis. The American Journal of Sports Medicine.
- Webster KE et al. 2019. What is the evidence for and validity of return-to-sport testing after anterior cruciate ligament reconstruction surgery? A systematic review and meta-analysis. Sports Medicine.
- Getgood AMJ et al. 2020. Lateral extra-articular tenodesis reduces failure of hamstring tendon autograft anterior cruciate ligament reconstruction: 2-year outcomes from the STABILITY study randomized clinical trial. The American Journal of Sports Medicine.
- Kuršumović K et al. 2020. Relationship of graft type and vancomycin presoaking to rate of infection in anterior cruciate ligament reconstruction: a meta-analysis of 198 studies with 68,453 grafts. JBJS Reviews.
- Gaskill T et al. 2015. The prevalence of symptomatic deep venous thrombosis and pulmonary embolism after anterior cruciate ligament reconstruction. The American Journal of Sports Medicine.
- Obermeier MC et al. 2018. Examination of early functional recovery after ACL reconstruction: functional milestone achievement and self-reported function. Sports Health.
- Salem HS et al. 2021. Return to driving after anterior cruciate ligament reconstruction: a systematic review. Orthopaedic Journal of Sports Medicine.
- Grindem H et al. 2016. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. British Journal of Sports Medicine.
- Beischer S et al. 2020. Young athletes who return to sport before 9 months after anterior cruciate ligament reconstruction have a rate of new injury 7 times that of those who delay return. Journal of Orthopaedic & Sports Physical Therapy.
- Kyritsis P et al. 2016. Likelihood of ACL graft rupture: not meeting six clinical discharge criteria before return to sport is associated with a four times greater risk of rupture. British Journal of Sports Medicine.
Frequently asked questions
Why do ACL tears happen?
How can I prevent this injury from happening?
Before playing sport, certain exercises have been shown to decrease the risk of ACL injury when performed regularly. It is best to incorporate these exercises into your warm-up program.
The main components of these exercises include:
- Core training: hip and trunk muscles
- Neuromuscular control and balance: jump and land techniques
- Plyometrics and agility
- Strength training of the quadriceps and hamstrings
Am I too old to have an ACL reconstruction?
There is no fixed age limit when you can have an ACL reconstruction. The decision to proceed with surgery is multifactorial and will depend on the presenting symptoms, the duration of time you have had an ACL tear for and the presence of cartilage damage or arthritis within the knee. If you are uncertain about whether an ACL reconstruction is in your best interests, Dr Vishal Pai can talk through the options for your knee with you.
What is a lateral tenodesis and how does it help reduce ACL graft reinjury?
A lateral tenodesis involves taking a strip of tissue (1 cm thick and 8–10 cm long) from the iliotibial band on the outer side of the knee and rerouting it beneath the lateral collateral ligament. It provides additional rotational control of the knee. It is performed at the same time as an ACL reconstruction in selected patients, with the aim of lowering the risk of re-injury.
Read more about lateral tenodesis.
I have a torn meniscus as well as an ACL injury, will you repair the meniscus at the same time?
Where a meniscal tear can be repaired, repairing it is generally preferable to removing it. The meniscus acts like a cushion to support your cartilage. Having a torn meniscus is a common associated injury when you have an ACL tear. Meniscal tears found during your operation are usually treated at the same time as your ACL reconstruction. If a meniscal repair is performed, it will slow your rehabilitation in the early weeks after surgery as the repair needs to be protected. However, thereafter you will resume your ACL rehabilitation as normal. The advantage of performing the meniscal repair at the same time as the ACL reconstruction is that the repair may be more likely to heal. The bleeding into the knee that occurs after an ACL reconstruction is rich in growth factors, which promote tissue healing.
Read more about meniscal repair.
How long does an ACL reconstruction take, and will I stay in hospital?
An ACL reconstruction usually takes 1–2 hours. It takes longer if other work, such as a meniscal repair or a LEAP, is done at the same time. Most people stay in hospital overnight.
When can I walk after an ACL reconstruction, and how long will I need crutches?
Dr Vishal Pai usually lets you put weight on your leg straight away, and he doesn’t use a brace. Most people use crutches for 2–3 weeks, until they can walk without a limp. [12] If your meniscus (the cartilage cushion inside the knee) is repaired during the same operation, you may need to limit the weight on your leg for 6 weeks to protect the repair. Dr Vishal Pai will tell you after the operation if this applies to you.
Avoid resting with a pillow under your knee. It feels comfortable, but it makes it harder to get the knee straight.
When can I swim after an ACL reconstruction?
The wound should be kept dry for 2 weeks following the operation. Once the wound healing is reviewed at your 2-week post-operative consultation, you will be able to shower with no wound dressings on. Participating in pool-based rehabilitation or swimming is not recommended for 3 weeks after your operation as it may increase the risk of infection.
When can I drive and go back to work after an ACL reconstruction?
To drive safely, you need to be able to brake hard in an emergency. Dr Vishal Pai’s usual advice is that the earliest you can drive is 4 weeks after surgery on your left knee if you drive an automatic, and 6 weeks after surgery on your right knee, or on either knee if you drive a manual. [13] You should also be off strong pain medication and walking comfortably, and Dr Vishal Pai will confirm when you can drive at your follow-up visit.
Most people with a desk job need about 3–4 weeks off work, and up to 6 weeks if the work is physically demanding. Dr Vishal Pai will give you a medical certificate when you leave hospital.
When can I return to sport after an ACL reconstruction?
Dr Vishal Pai recommends waiting at least 12 months before you return to competitive sport. At that stage, if your physiotherapist feels you are ready, they will do return-to-play testing. After that, timing depends on your test results and how you’ve progressed with rehabilitation, so there is no fixed date.
Going back too early raises the risk of another injury. Studies show the risk of another injury falls with each month you wait, up to about 9 months after surgery. It is much higher if you go back before 9 months, or before you have passed your return-to-sport tests. [14] [15] [16]