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Knee ligament injuries

What are knee ligament injuries?

Knee ligaments connect the bones and cartilage, as well as holding together and supporting the knee joint. They are made of tough, rubbery connective tissue. Four major ligaments support and stabilise the knee and these can be injured during sports such as rugby, tennis, football or skiing.

  • The main ligaments in the knee are the two cruciate ligaments – the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL); these are in the middle of the knee, crossing over each other centrally
  • The collateral ligaments are the medial (inner) collateral ligament (MCL) and the lateral (outer) collateral ligament (LCL)
  • As well as the four major ligaments, the anterolateral ligament (ALL) runs along the outside of the knee and is often damaged at the same time as the ACL

Fraser’s ACL repair story

“If it weren’t for this surgery I wouldn’t even have a season of skiing ahead of me. Now, I’ve even managed to get the season going ahead of when I normally would.”

Anterior cruciate ligament (ACL) injuries

The ACL is one of the main stabilising ligaments in the knee, connecting the thighbone to the shin bone. ACL injuries are increasingly common, particularly during sports such as football, tennis, squash, rugby and skiing, and currently affect around 40,000 people in the UK each year, including increasing numbers of children.

The ACL is in the middle of the knee and controls rotation as well as the forward movement of the shin on the thigh bone. If it’s torn, the knee becomes unstable when it is twisted and can give way, as well as losing its full range of movement. As the knee gives way, the delicate structures inside it, as well as the joint surface and meniscal cartilages, frequently become damaged.

Anterior cruciate ligament (ACL) injuries

Anterolateral ligament (ALL) injuries

The anterolateral ligament (ALL) runs along the outer part of the knee, providing stability when pivoting. ALL injuries – caused during twisting movements – affect around 30% of patients who have an anterior cruciate ligament (ACL) injury. Having ALL reconstruction surgery alongside ACL reconstruction, as part of the same procedure, significantly improves the long-term outcome.

Medial collateral ligament (MCL) injuries

One of the most commonly injured ligaments, the MCL provides stability to the inner (medial) part of the knee and feels tight when your leg is straight. It connects your thigh bone to the bone of the lower leg and stops the knee bending inwards. It’s often injured when the knee is knocked sideways and, in some cases, can be damaged alongside other ligaments in the knee.

Posterior cruciate ligament (PCL) injuries

The PCL lies behind the anterior cruciate ligament (ACL) in the middle of the knee, connecting the thigh bone to the shin bone. It controls backwards movement of the shin bone and, although it’s larger and stronger than the ACL, it can be injured by a direct blow to the shin, causing it to move too far backwards towards the thigh. PCL tears account for around 20% of knee ligament injuries.

Lateral collateral ligament (LCL) and posterolateral corner (PLC) injuries

The LCL and PLC stabilise the outer side of the knee and can be injured alongside other knee ligaments. The PLC is a collective name for a group of structures in the outer back corner of the knee. If damaged, as part of an acute injury, these structures can be repaired. Adrian has developed a minimally invasive PLC reconstruction technique that has become popular globally and is now carried out by many leading knee surgeons round the world.

Multi-ligament knee injuries

When two or more ligaments are injured at the same time, this is known as a multi-ligament injury. In most cases there are also cartilage injuries or a meniscal tear, as well as knee instability. If you have a multi-ligament injury, there is also a greater risk of injury to the major blood vessels and nerves around your knee; this may mean you need to have multi-ligament surgery, which can involve more than one operation to stabilise the knee and prevent further damage.

Knee consultants

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