ACL Injury

The anterior cruciate ligament (ACL) is one of your most important knee ligaments. It helps keep your joint stable during activities that involve twisting, turning or side-stepping.

What is ACL injury?

Your ACL provides important information to the muscles around your knee by sending signals through your nerves (proprioception). This helps protect your knee during activities. Your ACL runs from the back of the femur (thigh bone) to the front of the tibia (shin bone).

When your ACL is injured you may experience a popping sensation or sound, this is usually followed by immediate swelling due to bleeding into your knee (haemarthrosis).

Damage can occur during a non-contact twisting movement. Additional knee injuries can occur at the same time. These can include cartilage tears or damage to your joint surface.

When your ACL is torn the knee can feel like it is giving way, especially during twisting activities. Left untreated it can eventually lead to osteoarthritis in your knee.

Have I torn my ACL? How do I treat an ACL tear?


Symptoms of an anterior cruciate ligament tear include feeling unstable or feeling that your knee gives way. This can be accompanied by swelling and pain. Usually patients will experience this when performing a twisting movement however a small number experience this when doing even simple activities.


A torn ACL can be difficult to diagnose. When the injury is fresh it can be too uncomfortable to perform an examination. Additional knee injuries at the same time can also make it difficult. If this is the case then an MRI scan will be needed to accurately diagnose the extent of the damage, a torn ACL cannot be seen with a simple x-ray.

As symptoms can sometimes only be felt when performing twisting activities problems from a torn ACL can worsen over time and put stress on other parts of the knee.

Late diagnosis of ACL injuries very common. Patients may try to return to their previous activities and sustain further damage to their knee. This can affect the result of reconstructive surgery.


There are different treatments for an ACL injury depending on your lifestyle.


If you have an active lifestyle, and wish to continue to have an active lifestyle including returning to high impact sports that involve rapid changes in direction then surgery to reconstruct the ligament is an option.


Patients with lower physical activity levels, or people, who do not participate in activities involving twisting, may find that completing a program of physiotherapy and rehabilitation will suffice. About one third of patients find that they are able to continue with their activities without major problems.

To treat an ACL injury without surgery you will need to undergo a supervised programme of physiotherapy. This will concentrate on these main areas:


To take the load off of your ACL the muscles around the knee must be strengthened, especially the hamstrings.

Balance & proprioception

The ACL tells your brain and muscles information about the position of your knee. To help compensate for the damage to the ACL other nerves must be retrained to perform this function.

A functional knee brace is sometimes prescribed to help patients with a damaged ACL.

Gareth Stables

Cheshire Orthopaedic surgeon, Mr Gareth Stables, is a fully UK trained Consultant Orthopaedic Surgeon specialising in knee surgery. Gareth has the highest qualifications possible for an orthopaedic surgeon in the UK, FRCS (T&O), and is on the GMC specialist register for Trauma and Orthopaedic surgery.

Gareth specialises in; keyhole or knee arthroscopy surgery, ligament reconstruction surgery, knee osteotomy and knee replacement surgery. He has over 15 years of experience in the field having qualified with a commendation in 1998 from the University of Liverpool Medical School.

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