Aug 15, 2023

Everything you need to know about ACL injuries

Most people will have heard of ACL injuries as they are common amongst those who participate in pivoting sports, such as football, skiing, rugby and netball.

ACL injuries hit the headlines in the lead up to the Women’s Football World Cup this summer, with many professional players side lined due to the injury. Women’s football is one of the fastest growing sports in the UK, particularly since the Lionesses won the Women’s European Championships in 2022, with a 15% increase in female youth teams registered with the Football Association and an estimated 100,000 more girls playing football than five years ago.

So, what do you need to know when it comes to ACL injuries? Mr Saket Tibrewal, Consultant Trauma and Orthopaedic Knee Surgeon at Capital Orthopaedics answers the most commonly asked questions around ACL injuries and what to do if you sustain this injury?

What is an ACL injury?

Your knee is a hinge joint comprised of three bones: the thigh bone (femur), shin bone (tibia), and kneecap (patella). These bones are connected by bands of tissue called ligaments.  A ligament is a structure that holds the bones together and helps to control joint movement or motion.  There are 4 main knee ligaments: there is a ligament on each side of the knee called the collateral ligaments, and 2 ligaments deep inside the joint called the cruciate ligaments, which cross each other.

The anterior cruciate ligament (ACL) runs through the middle of the knee.  The ACL helps to control rotational movements of the knee as well as preventing the shin bone from sliding forwards in front of the thigh bone.  Behind the ACL is the posterior cruciate ligament (PCL), which prevents the shinbone from sliding backwards behind the thigh bone. The PCL is thicker and stronger than the ACL and is damaged less often.

Most ACL injuries occur during sports that involve sudden changes in direction, like football or skiing.  ACL injuries can also be caused by excessive bending or straightening of the leg, a blow to the knee, twisting movements, or awkward landings when jumping (e.g. basketball, netball, rugby).  They can also be caused by other mechanisms such as falls or motor-vehicle accidents.

Your ACL injury will be graded on a scale from 1 to 3:

  • Grade 1: A grade 1 injury means the ACL has been overstretched or “sprained” but not torn. The ACL still provides stability to the joint.
  • Grade 2: Grade 2 injuries are more rare.  The ACL is stretched and partially torn.
  • Grade 3: Grade 3 tears are when the ACL is fully torn and does not provide stability to the joint.

What are symptoms of an ACL injury?

If you injure your ACL, you may hear a popping sound and feel severe pain in your knee. Your knee may feel unstable and give way, or feel like it will, and you may not be able to put any weight on it.

If you’re playing sport, you are unlikely to be able to carry on as you will not be able to walk on it. You will usually develop swelling around your knee joint within an hour or two, and you may lose the full range of movement in your knee.

You may feel a loss of control over your knee and it may continue to give way with certain activities or movements.

You will need to see a doctor or physiotherapist to get an accurate diagnosis of your injury.

How do you treat an ACL injury?

If you do get injured it’s important you seek help as soon as possible, this can be from a doctor or a physiotherapist who will be able to support with treatment. There are some things you can initially do to help reduce swelling, pain and aid recovery.

The initial treatment will be to control your pain and swelling using the POLICE method. Further treatments may include physiotherapy, pain killers and if required, surgery.

POLICE Method:

  • P: Protect the injury from further damage. You may need to rest after the injury, and consider using some form of support or a splint.
  • OL: Optimal Loading. Start to put weight on your injury and build up your range of mobility.
  • I: Ice. Place a cold compress such as a bag of ice or frozen peas, wrapped in a towel onto the injury.
  • C: Compress the injured using a bandage to help reduce swelling.
  • E: Elevate the injury.

Does an ACL injury always require surgery?

Further treatment for an ACL injury depends on how bad your injury is.

In Grade 1 injuries, the ACL still provides stability to the joint and these do not require surgery.  Grade 2 injuries (partial tears) can usually be managed without the need for surgery, through the use of rest, anti-inflammatory medications, and physiotherapy.  If non-surgical management does not work or there is persistent instability, then these injuries may require surgery.  Grade 3 tears with persistent instability  require surgery which is called an ACL reconstruction.

Your surgeon will discuss all treatment options and whether you would benefit from surgery to repair or reconstruct the ACL. This is often the case for very active people who have a complete tear of the ACL and instability of their knee.

In the majority of cases it is usually best to wait for any surgery until the swelling in your knee has gone down and you have recovered a full range of mobility.

ACL reconstruction is usually carried out arthroscopically (keyhole surgery). Because keyhole surgery uses only small incisions, patients may benefit from reduced scarring and faster recovery times.

To reconstruct the ACL, a piece of tendon (the donor graft) must be acquired from another part of the patient’s body – there are a variety of options with the most common being hamstring, quadriceps or patella tendon.  Holes are made in the thigh bone and shin bone and the tendon graft is placed and secured into position with screws or special buttons.  This tendon acts as a scaffolding and over time the body converts the tendon graft tissue into a more ligament-like structure.

The entire surgery usually takes between 60 to 90 minutes to complete, dependent upon the complexity and other associated procedures required, such as cartilage repair or extra-articular augmentation of the knee.

Some patients may require a knee brace and most can go home on the same day.

Following surgery, it usually takes 12 months to return to full unrestricted activity, such as contact sports, and so you will need to be prepared to undergo an intense and lengthy period of physiotherapy. You may however return to other activities such as running, cycling and swimming earlier as directed by your physiotherapist.

How can I prevent getting an ACL injury?

It is unequivocal that injury prevention programmes are key in reducing ACL injuries.  They have been shown to reduce the risk of ACL injuries by 50% in all athletes, and by 2/3 in female athletes sustaining non-contact ACL injuries.

I am a regional ambassador for the charity Power Up To Play, which is the first of its kind in the UK.  The primary purpose is to reduce knee injuries in children playing grass roots sports using a standardised evidence-based warm up, however these programmes are not just limited to children and are easy to access and implement for everyone.

All injury prevention programmes share common themes which include improving flexibility, strength (particularly core, hips and legs), balance, agility and the ability to jump and land safely.

Here are some of my top tips for injury prevention:

  • Always warm up properly before playing any sport.
  • Ensure to include stretches into your routine, in particular your thighs, calves and hips.
  • Strengthen your hips and thighs as they provide support to your knees and can help prevent ACL injury.  Squats, walking lunges and core strengthening are some exercises to include in your routine.
  • Balance, agility, jumping and landing can all be improved with practice.
  • Rest is essential.

Why are so many women getting ACL injuries?

ACL injuries are more common in women than men, and female athletes are 4 to 8 times more likely to suffer an ACL injury than their male counterparts. What is happening in Women’s sports at the elite level is merely scratching the surface of a much deeper issue. There has been a rapid rise in the number of young athletes sustaining this injury, with the biggest increase seen in teenage girls.   With the FIFA Women’s World Cup taking place this summer, interest and uptake of the sport will continue to rise and so too the incidence of ACL injuries amongst female footballers.

It is still not clear why ACL injuries are more common in women than men, and further research is required to investigate this.  However it is thought to be a combination of multiple factors including anatomical differences and hormone levels.

Anatomically, the female pelvis is wider, which changes the mechanics of how the thigh bone, tibia, and femur function.  This puts more stress on the soft tissues that support the joints.  This higher stress can lead to either a chronic (overuse) or acute (sudden) injury.

Additionally, women have less muscle mass around their knees than men,  which can lead to instability and a higher chance of tearing a ligament if it is overstretched.

Women also produce less testosterone, a hormone that supports muscle density, and more oestrogen, which may contribute to increased laxity in ligaments and joints.  This could predispose them to higher risk of injury.  Another theory is that of the menstrual cycle playing a key role in injury risk, as oestrogen levels fluctuate through the cycle this might make women more prone to injury when levels are higher.

There are also theories that the “gendered” sports environment may be a factor.  Examples of this include the fact that women’s football boots are simply smaller versions of those designed for men, rather than being specifically tailored for women’s feet. Female athletes may also have less access to injury surveillance and management initiatives.

What changes are needed to prevent more female athletes suffering from an ACL injury?

The first step is raising awareness and acceptance of the problem, which has happened naturally due to the large number of high profile cases and media coverage.

We must look to create an appropriate environment for women’s sports, at all levels, that accounts for gender based differences. Removing established stigma, such as those associated with women who participate in strength and conditioning training, would be a good starting point as we know that poor neuromuscular control is a significant, but modifiable, risk factor for ACL injuries.

Across all sports, integrated neuromuscular training programs (biomechanical, neuromuscular control, and strength training techniques) have effectively improved performance levels and decreased the risk of ACL injury.  Injury prevention programmes do not require extensive commitments in time and are simple to implement.


Mr. Saket Tibrewal FRCS (Tr&Orth)

Consultant Knee Surgeon

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