Anterior cruciate ligament


Now that you have suffered an injury to your anterior cruciate ligament (ACL) and the diagnosis has been confirmed, you have decided to have an operation to repair it.  The information here should answer any further questions you may have.  If anything is not covered, please ask your surgeon or physiotherapist.

Will I be seen before my operation?

You may be seen about 1 - 2 weeks before your operation in the pre-operative assessment clinic. This is to ensure you are medically fit  to have it performed and for infection control screening.  You will be seen again on the suite before going to the operating theatre.  The operation will be explained again and a consent form will be signed where the final details will be checked and the knee being operated on will be marked.

How will my operation be done?

Most patients will have a reconstruction using two of the hamstring tendons taken from behind the knee and thigh.  It is surprising how little their removal affects the knee.  The tendons are then fastened into the knee using a system of screws and pins by a keyhole technique (arthroscopy).  The new ligament is placed in the centre of the knee exactly where the original was.  Any repair or removal of torn cartilage will be done at the same time.

Will there be many scars?

The hamstrings graft is removed through a 4cm wound over the top of the shin just below the knee.  The keyhole part is done through two 0.5cm wounds over the front of the knee. You may notice some other small puncture wounds for placement of the graft fixing devices. 

Are there any alternatives?

Some patients are not suitable for a hamstring graft or there may be reasons to use a different one.  The usual alternative is to use a strip of the tendon from below the patella (kneecap) instead.  The wound is longer, the recovery is a little slower initially and it can be more difficult to kneel afterwards, but the end result is the same.  Fixation of the graft is stronger and it may be better for some sports.  In some instances, graft may be taken from the other leg.  In some circumstances graft is used from a tissue bank (allograft).  Your surgeon will help to guide you through these choices.

Will I be asleep?

Yes.  The operation is done under a general anaesthetic for most people, but it is possible under a spinal anaesthetic that just makes the legs numb.

How long does it take?

The operation takes about 1 to 1½ hours.

What will it feel like afterwards?

As the operation is done by a keyhole technique it is not particularly uncomfortable. Any pain you may feel is easily controlled with painkillers.

How long will I be in hospital?

Most people come in on the day of surgery and go home the next day.

What will I be able to do when I go home?

You can walk on the leg, but will need some crutches for the first week or so.  Occasionally it may be necessary for you to wear a light splint on the knee for a short while. The physiotherapist will give you a thorough briefing on what to do before you leave hospital.

What physiotherapy will I need?

After this type of surgery, rehabilitation is very important.  You will start your physiotherapy one week after the operation when any splint is removed.  Rehabilitation is done following a set routine and will be explained by the physiotherapist before you go home (see also the Information leaflet: "Guide to Rehabilitation Following Anterior Cruciate Ligament (ACL) Injury and Reconstruction"). 

Will I be seen after my operation?

Yes.  You will be seen after your operation by your surgeon. After discharge you will be seen again 2 - 4 weeks later in the follow up clinic. This is in addition to the physiotherapy course outlined above.

In the long term (after 1 year) you will not need to come to hospital for follow up unless there are any problems. However, we are keen to find out how our patients are progressing. You may therefore be contacted to complete a postal questionnaire some time after your operation. Any information returned would be handled sensitively and confidentially, it may be stored on a secure computer register.

When can I drive?

Most people are fit to drive 10 to 14 days after surgery.  You can discuss this further with your surgeon. You are also advised to contact your car insurance company before you start to drive again. 

When can I go back to work?

This depends on your job.  If it is an office job, you can go back after 2 weeks - sometimes even quicker.  If you have a manual job, especially if it involves kneeling or climbing you will need longer.

When can I play sport again?

It is very important that you do not risk damaging the new ligament too soon after the operation.  It is easy to snap or loosen the repair in the first 3 or 4 months if you are not careful.  Your surgeon or physiotherapist will give you appropriate individual advice, but we advise against non-contact sport for 6 months and contact sport such as football for at least 8 months. 

How soon after my operation can I fly or go on holiday?

You should be able to go away within the UK after 48 hours, providing any long journey is appropriately broken. However, you should ensure that you do not miss any of your physiotherapy appointments. Flying immediately after lower limb surgery is associated with an increased risk of deep vein thrombosis (see below). Although no fixed guidelines exist we recommend that you should not fly for 2 weeks following an ACL reconstruction.

What can go wrong?

This type of surgery is generally very safe, but there are a few possible problems you should know about.

Anaesthetic: Rarely problems can occur related to your general health and the anaesthetic. The majority of potential problems should be picked up at the pre-assessment clinic. Your anaesthetist will be able to discuss this further with you.

Numbness: Most patients will be aware of a small patch of numbness just to the side of the scar or over part of the shin.  This usually gets even smaller with time and causes no trouble

Swelling: Some swelling is common afterwards but usually disappears after a few weeks.

Bleeding: This can make the knee stiff and swollen.  The blood can easily be removed through a needle in hospital.

Infection: Some redness around one of the wounds is treated with antibiotics.  Very rarely, infection develops inside the knee.  This needs further surgery to drain and wash it out as well as antibiotics.

Stiffness: Early physiotherapy gives a good range of movement, but some people find their knee remains stiff.  A further keyhole operation is occasionally needed to free it up.

Giving-way: After the operation the knee feels weak.  As the muscles regain strength this improves quickly.  Very rarely the graft comes apart either due to another injury or because it simply stretches.  Another operation may be needed if this happens.  Overall we obtain a stable knee without complications in 95% of patients.

Deep vein thrombosis: This can occur to anyone under going lower limb surgery. The risk is greater if you have had one before or are on the oral contraceptive pill/hormone replacement therapy (which should be stopped 6 weeks before operation). They rarely cause direct problems, but can potentially be serious because of the risk of spread to the lungs (pulmonary embolism). Treatment usually involves taking warfarin (to make the blood clot less easily) for a 3 month period.

Can it be done again if I injure my knee?

Yes, but it is more difficult and you are less likely to get a stable knee.

Will I get arthritis later?

We know that patients with an unstable knee are more likely to get arthritis.  Even though the operation may seem successful in giving you a stable knee that works well, there is still an increased risk of arthritis later in life.

What do I do if I have a problem after my operation?

You can contact the suite where you had your operation.  If you remain concerned, contact your GP or attend your local Emergency Department.

If you have any more questions, please ask your surgeon


Alexandra Hospital
0161 495 7000/1/2/3
Spire Manchester
0161 447 6600
Practice Manager
0161 495 6869