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Knee ligament injuries: everything you need to know

A person skiing

The knee joint is commonly injured during competitive and recreational sporting activities. About 40% of all sports injuries are caused by damaging a band of tissue called the anterior cruciate ligament (ACL) in your knee.

It can be daunting if your doctor tells you that you have injured the ACL. We have all watched footballers being carried off the pitch, but somehow never imagined that it could happen to us. Mr Tarun Taneja, Consultant Orthopaedic Knee Surgeon at Highgate Hospital, answers your frequently asked questions about ACL knee injuries.


What is the anterior cruciate ligament (ACL) and why is it important?

The ACL is a major ligament in the knee. Ligaments are bands of tissue that connect one bone to the other. They hold the bones in place and give stability to the joint and surrounding structures, such as the muscles.

If you tear the ACL, the two ends do not heal back together. Surgery involves putting a new ligament in the knee to replace the torn ACL using a graft (new tissue).


How do I know if I might have injured my ACL?

Unlike what most people might think, the most common way of injuring the ACL is not through a tackle during a game. Instead, this type of injury often happens in situations that do not involve contact with another player or person. You may be trying to change direction or pivot (turn), while your foot is firmly fixed on the ground. This creates force, which can stretch the ACL beyond its limits.

Sports like football, soccer, skiing and netball all involve pivoting movements and can lead to ACL injuries. You may hear a popping sound and the knee often swells up shortly afterwards due to bleeding within the joint.


I have been told that I may also have a meniscus injury. What does this mean?

The meniscus is a different structure in the knee joint. It is a C-shaped pad between the thigh bone (femur) and shin bone (tibia).

Your knees have two menisci: one on the inside and another on the outside. They act as shock absorbers and help to keep the knee joint stable. If you have surgery, most surgeons treat a meniscal tear at the same time as an ACL injury.

The treatment options include repairing the torn meniscus (meniscal repair) and trimming the meniscus to remove the torn part (partial meniscectomy). As not all surgeons perform meniscal repairs, it is important to choose your knee surgeon carefully. Personally, I try to preserve the meniscus and perform a meniscal repair if possible. This is something that your surgeon will discuss with you before surgery.


Do I need surgery to treat an ACL injury?

Whether you need surgery for an ACL injury depends on many factors. These include:

  • what type of ACL injury you have
  • whether you have any other injuries, such as meniscal tears
  • your current levels of activity
  • your future goals

It is a good idea to start physiotherapy as soon as possible after your injury has been diagnosed. This helps to strengthen your muscles and maintain your range of knee movement. Even if you eventually have surgery, physiotherapy at this early stage will help you to recover.


What happens during ACL surgery?

As the original torn ligament does not heal, surgery involves making a new one. This is done by using a tendon (strong piece of tissue), often from the same knee, to replace the ACL. The tissue used to replace the ACL is called a graft.

The most commonly used graft is from the hamstring tendons. This is the length of tissue behind your knee that joins your thigh muscles to the bones in your lower leg. Other options include the patellar tendon (tissue below the knee cap) and the quadriceps tendon (tissue that attaches the knee cap to your thigh muscles).

The procedure carried out is called an arthroscopy. This is a type of keyhole or minimally invasive surgery, which only involves small cuts in the knee. Your surgeon uses a thin, flexible tube called an arthroscope with a light and camera to see inside your knee clearly. They also insert other small instruments to remove the torn ligament. The surgeon then fixes the graft to the bone with special buttons, screws or staples. This tightens the knee and prevents loose ligaments and instability due to the original injury.


How long does it take to recover from ACL surgery?

Surgery is not the end, but rather the start of your journey to recovery. There is a long period of rehabilitation with the physiotherapy team, which is crucial to achieve a good outcome.

Typically, it takes at least nine months before you can return to competitive sport. However, you can resume activities like jogging and cycling earlier by following a graded recovery programme. This is when you gradually increase your level of activity over time.

Although an ACL tear is a significant injury, it should only be a temporary setback. With modern surgical and rehabilitation techniques, most people can return to their previous fitness level.


Is there a way to prevent ACL injuries?

It is not possible to avoid injuries altogether, but there are programmes designed to reduce the risk of injuring your ACL. These programmes focus on improving muscle strength and neuromuscular control (how your brain controls the movement of your limbs). They also teach you useful techniques, such as how to land from a jump. An example is the FIFA 11+ injury prevention programme for football players, which you can access online.


About Mr Tarun Taneja

Mr Tarun Taneja is a Consultant Orthopaedic Knee Surgeon at Highgate Hospital. His practice focuses solely on the knee joint. He treats many sports knee injuries, including ACL and meniscal tears. There is more information about knee injuries, including educational videos, on Mr Taneja’s website at:

To make an appointment with Mr Taneja at Highgate Hospital, please call 020 3918 9522 or complete this form.


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