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ACL Reconstruction

ACL reconstruction is a procedure where a torn anterior cruciate ligament (ACL) is repaired. The ACL is a tough band of tissue that connects your thighbone to the shin bone within the knee.

Also known as:  Anterior Cruciate Ligament Reconstruction

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Everything you need to know

ACL reconstruction is a procedure where a torn anterior cruciate ligament (ACL) is repaired.

The ACL is a tough band of tissue that connects your thighbone to the shin bone within the knee. The ACL runs diagonally inside the knee and helps it stable. It also helps to control the backwards/forwards movement in your lower leg.

ACL injuries are one of the most common knee injuries and frequently occur in sports such as football, rugby, skiing, tennis and squash.

Related Conditions

Common causes of an ACL injury include:

  • Sudden twisting movements (frequently occur when ski bindings do not release during a fall)
  • Pivoting with your foot firmly planted
  • Collisions (such as in a football tackle)
  • Stopping or changing direction suddenly
  • Landing incorrectly after a jump

If you injure your ACL, you may hear a popping sound and will notice pain. Your knee will swell within an hour or two of the injury and it could also feel unstable. You may also notice your knee’s range of motion is reduced and certain movements, like turning on the spot, become very difficult.

Physiotherapy can successfully help with an ACL injury if you are relatively inactive, engage in moderate exercise and recreational activities, or play sports that do not put stress on the knees.

ACL reconstruction is generally recommended if:

  • You’re an athlete and want to continue in your sport, especially if it involves jumping or pivoting
  • More than one ligament is injured
  • You have a torn meniscus (shock absorbing cartilage) that also requires repair
  • Your knee keeps giving way or feels like it’s going to
  • You’re young (though other factors, such as activity level and knee instability, are more important than age)

Before Surgery


Whether you have knee surgery will depend on the extent of damage to your ACL, if you have other injuries in your knee, and if your quality of life is being affected.

If your knee feels stable and you don’t notice an impact on your day-to-day life, you may decide that pain relief and physiotherapy are enough.

However, if your knee feels unstable, keeps giving way, and you are not able to take part in activities you enjoy, ACL surgery could be a good option for you.

If you have injured your ACL and are worried, book an appointment with one of our specialist knee surgeons. They will assess your knee and if needed refer you for an MRI of your knee to see the extent of injury. Your doctor will thoroughly discuss your options with you. If surgery is recommended, they will explain the risks and benefits so you can make an informed decision.


If you decide to have surgery, you may need to wait for any swelling to go down and also see a physiotherapist for ‘prehab’. This will aim to increase the range of motion in your knee and strengthen the surrounding muscles as this will lead to better outcomes after surgery. It could take around three weeks before your knee is ready for surgery.

In the run up to surgery, you should regularly do your prehab exercises and avoid movements that could worsen your injury, including twisting and jumping.

If you would like physiotherapy help, we have an excellent therapies department at the hospital who can support you before and after surgery.


Before your surgery, you will need to come into hospital for a pre-assessment, where we can check your fitness for surgery. This is a standard check and includes a physical exam, blood tests, heart and lung function tests as well as an MRSA test. We will also give you some specific antibacterial soap and lotions to use in the run up to the procedure, which will help reduce your risk of contracting MRSA.

If you take any blood thinners—for example, warfarin or aspirin, tell your doctor straight away, as you may need to stop taking these or modify your intake from a week before surgery. Your doctor will give you specific instructions if this is the case. You should also tell your doctor if you take nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen.

Surgery day

An ACL reconstruction is a day-patient surgery. This means you can be treated and go home the same day.

You should stop eating six hours before surgery. Two hours before, you should stop drinking (including water), chewing gum and sucking boiled sweets. Brush your teeth with toothpaste only on the morning of surgery.

Wear loose, comfortable clothes and bring a small bag with things you might need during your stay. Items to remember include a toothbrush and toothpaste, your phone and a charger, and any prescription medications. Your doctor will let you know if you can take any medications with a sip of water before surgery or if you should wait until after.

Once you have arrived and are settled in your room, a nurse will monitor your vital signs (such as body temperature and blood pressure) and run through your medical history, medications and emergency contacts.

Your doctor will then once again run you through the procedure and ask you to sign a consent form for surgery.

During Surgery

Before starting the procedure, you will be anaesthetised. There are different options, including general anaesthesia where you are unconscious and need a breathing tube to help you breathe, and spinal where anaesthetic is injected into your spine to numb the lower half of your body. With spinal, you can also be given sedation to help you relax.

To start the ACL reconstruction, the surgeon will make small incisions around the knee. From here, they’ll insert a device called an arthroscope into your knee. This is a small tube with a tiny light and camera that sends images to a monitor. Your surgeon will use this to examine the interior of your knee and as a guide throughout the operation.

A torn ACL cannot be repaired by stitching it back together. It needs to be reconstructed using tendon from another part of your body, a donor, or synthetic material.

Your surgeon will remove the damaged ligament and replace it with the new tissue, which will be connected to your thigh and shin bones. To finish, your surgeon will close the incisions using stitches.

Typically, ACL reconstruction surgery takes one to three hours to complete.

After Surgery

Once we’re happy you’re doing well, we will take you to your private room where you can start your recovery.

Our nursing team will make regular checks to make sure your recovery is going to plan, and they will also encourage you to get up and walk as soon as possible. They will provide you with a knee brace or crutches to help you get around. Your surgeon will also visit you and let you know how surgery went. Then, once you’ve had some food and drink, you can go home. You will need someone to collect you and stay with you overnight as general anaesthetic and sedation can make you feel very tired for around 24 hours. During this time you should not drink alcohol, cook or make important decisions.

If possible, arrange for someone to help you for a couple of weeks post-surgery as well, as your knee will be bruised, swollen and quite painful for 1-2 weeks after surgery. During this time, take your prescribed painkillers, apply a cold wrap to your knee, and keep your leg elevated as much as possible. When moving around use crutches or a knee brace as you should not put too much weight on your knee at this point.

It will take approximately two weeks for your wound to heal, and you should see your doctor at this point for a post-surgery check, where any clips or non-dissolvable stitches will be removed. Dissolvable stitches should disappear on their own after around three weeks.

After 2-3 weeks, you should be able to start walking without crutches/the brace and put more weight on your knee. You should be able to return to office work at this point as well, though if you have a manual job, you may have to wait up to 3 months.

From 2 weeks onwards, you should do your physiotherapy exercises regularly as these will help improve your balance, flexibility in your knee, and increase the strength in the surrounding muscles. You should be able to start driving again after 3-4 weeks or once putting weight on your knee feels comfortable. You should find that full range of motion is restored between 6 – 14 weeks, and you can do more activities, such as running from around 3 -5 months.

In the weeks following an operation, patients have a slightly higher risk of a blood clot, so will need to avoid flying. You should wait six weeks before taking a short haul flight (under six hours) and 12 weeks before taking a long-haul flight.

Many people, especially those who live an active lifestyle, will be tempted to rush the recovery process. But this is to your own detriment. When you’re recovering from ACL reconstruction, it can take up to 6 months before the new and intact ligament is working to its full potential.

A physical therapist can help guide you through the recovery process, and our hospital has a great team of physiotherapists who can support you through your recovery.

How to pay for your treatment

If you’re… paying for yourself

Did you know you don’t need private medical insurance to come to St John & St Elizabeth Hospital? As a self-pay patient, you can access safe, outstanding quality health care at times to suit you.

For scans and tests, as well as to see most consultants, you’ll still need to be referred by a medical professional like your GP, but as a self-pay patient, the process is more straightforward. You won’t need authorisation from an insurance provider, and you’ll have greater choice of consultant and appointment times.

If you’re… insured

St John & St Elizabeth Hospital is approved by all major medical insurance companies. If you have a personal private health insurance policy, or your company provide it for you, you can use it to pay for your care from your initial consultation through to treatment, surgery and aftercare such as physiotherapy. Not all private health insurance plans cover the same things. It’s very important to check exactly what you are covered for with your insurance provider.



You will have an initial consultation with a specialist knee surgeon.


Treatment plan

During this appointment, you will go through your medical history, have a knee exam and if needed, be referred for an up-to-date scan (such as MRI) of your knee. If surgery is recommended, your doctor will explain the risk and benefits of surgery and what to expect from recovery. Together, you will decide whether an ACL reconstruction is the best option for you.



Your knee needs to be in the best condition possible before surgery, as this will lead to better outcomes. Once your swelling has gone down, you should follow your physiotherapist’s exercise programme. This will aim to increase your knee’s range of motions, reduce stiffness, and strengthen the muscles near the knee.


Pre-op assessment

If you decide to go ahead with surgery, you will need to come in for a pre-assessment, which is a standard ‘fitness for surgery’ check.



The surgery will take 1 – 3 hours. You will be able to walk the same day with the help of a knee brace or crutches. You can go home the same day.



You will need to keep your wound clean and dry, take pain relief and have physiotherapy consistently. You will not be able to fly short-haul for six weeks or long-haul for 12 weeks. We have an excellent therapies team at our hospital that can support you throughout your recovery.



You will have a follow-up appointment with your doctor at two weeks, where any stitches will be removed. If needed, you may have further check-ups at 6 weeks, 12 weeks and 6 months.

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