ACL (anterior cruciate ligament) injury Tirohanga whānui ki tētahi wharanga ACL

An ACL injury is usually caused by:

• twisting or landing awkwardly
• a direct blow to your knee.

It is more common among people who play sports that involve a lot of pivoting and twisting. For example, rugby, netball and soccer.

It is also more common in women and teenage girls than men. You are more likely to have an ACL injury if there is a family history.

Symptoms of an ACL injury might include:

• a popping sound when the injury happens
• knee pain immediately after the injury
• swelling — immediately or within a few hours of the injury
• your knee feeling unstable, or give way, when you twist or pivot
• not being able to put weight on your leg
• feeling unsteady when you walk.

People often worry about developing arthritis after an ACL injury. As long as you did not hurt anything else other than your ACL, the risk of arthritis is low. But your risk increases if you:

• also damaged other parts of your knee
• have not been able to get normal movement back after rehabilitation or surgery
• are overweight.

If you have any symptoms of an ACL injury you should see your healthcare provider or a physiotherapist. They will examine your knee.

You may also need an x-ray to make sure their are no injuries to the bones. You are likely to need an MRI scan to confirm the diagnosis of a ruptured ACL.

After an ACL injury you should try to reduce any pain and swelling with:

• rest
• ice
• compression
• elevation.

If you wear a compression bandage, such as a Tubigrip, make sure to take it off when you go to bed.

Take regular pain relief — regular paracetamol provides good pain relief. Take it according to the instructions on the packaging, and never more than 2 tablets every 4 hours and 8 tablets in 24 hours.

Swelling will usually go down over a few days. Avoid jumping or twisting to protect your knee from any more damage.

• You may need crutches for a short time if it is difficult to put weight on your leg.
• You may need surgery to stabilise your knee — this will depend on how bad the injury is, your age, job, hobbies and level of sport.

If you have a fully functional knee that does not give way, you are unlikely to need surgery. In the first few weeks it is difficult to tell who will need surgery, so it is best to try strengthening exercises first.

Strengthening exercises

Strengthening exercises to help keep your knee stable are the best treatment. Start exercises around day 4 after your injury. Gradually increase how much you can move your knee and get your thigh muscles working.

Work through the following exercises in order. When you feel ready, move on to the next one. If you are not sure about these exercises contact your healthcare provider or physiotherapist.

• Start trying to straighten your leg, aiming to get it straight and fully extended.
• Strengthen your thigh muscles.
• Do single leg squats to start putting weight through your leg and improve your balance. Ask your healthcare provider or physiotherapist to show you how to do these.
• Once you can bend your leg more than 90 degrees, get more active. Use an indoor cycle if you have access to one or try swimming or upper body exercises.
• When you are comfortable doing so, start gentle walking.

If any of these exercises are painful, stop doing them and see a physiotherapist or your healthcare provider.

A physiotherapist will oversee any non-surgical treatment you have. You can go straight to a physiotherapist without having to see a healthcare provider first.

Find a physiotherapist in your region — Healthpoint (external link)

ACC almost always covers ACL injuries, but you may have to pay a surcharge. Ask your physiotherapist how much you will have to pay.

After assessing your knee, your physiotherapist will recommend a series of exercises to help you heal. This might include some time in a gym, but exercises you do at home can also work well. The exercises the physiotherapist gives you will help to:

• increase the strength of your thigh
• improve the strength of your spine, pelvis, hip and calf to reduce any effect the injury has on you
• improve your balance and agility
• improve the power in your leg
• prevent any further ACL injuries by improving your landing technique and reaction times.

They will include exercises specifically targeted to your sport or work. The aim is to get you moving normally again without worrying about your knee giving way.

It can take up to 9 months to get you back to sport. Your physiotherapist will test your knee and assess your progress to find out when you are ready.

If this rehabilitation programme does not work and your knee continues to give way, you may need surgery.

Surgery for an ACL injury

If you have completed a rehabilitation programme with a physiotherapist but your knee is still unstable, it is likely you will need surgery.

An orthopaedic surgeon will assess your knee and tell you if they recommend surgery. As well as having an unstable knee, other reasons you could need surgery include:

• you are nervous about movement
• you feel that you have some disability, or your knee stops you from doing things that are important to you
• you plan to return to sports that involve a lot of pivoting and twisting
• you do not have full movement (extension)
• you still have swelling and a weak thigh.

Even after surgery and the later exercise programme, 12% of people injure their knee again. It is important to follow a programme to avoid that.

Before surgery

It is best not to have surgery immediately after an ACL injury. The results are better after your knee has had time to settle down and you have strengthened your leg with a rehabilitation programme.

Surgery

Surgery to reconstruct your ACL can be done in a few ways.

Knee ligament surgery — NHS UK (external link)

After surgery

After surgery, you will need to follow the surgeon's instructions carefully until you see your physiotherapist 1 or 2 weeks later. Your physiotherapist will then give you another exercise programme to get your knee working properly again and strengthen your leg.

It will take at least 6 months and maybe as long as a year to fully rehabilitate your knee. It is essential that you follow your physiotherapist's instructions and do all the exercises. If anything is stopping you from doing the exercises, talk to your physiotherapist about it.