Lateral Collateral Ligament Injury

What is the Lateral Collateral Ligament (LCL)?

The LCL is a ligament on the lateral or outer side of the knee, that attaches between the femur (thigh bone) and the fibula. It helps to stabilise the knee and prevent excessive side to side movement.

How is the LCL injured?

An LCL injury typically occurs from direct contact to the inside of the knee that pushes the knee outward. It can also occur through twisting of the knee, or as part of a larger multi-ligament knee injury.

What problems does an LCL injury cause?

An injured LCL is called a sprain, which are graded on a scale.

Grade 1 sprains are associated with pain and swelling only, with nearly all the fibres of the ligament intact. Instability is rarely a problem.

Grade 2 sprains represent a partial injury to the ligament, and patients may feel some instability as they walk or run.

Grade 3 sprains represent a complete injury to the ligament, with almost all fibres disrupted. The knee is felt to be very unstable, with difficulty walking and running without the knee giving way.

The LCL also makes up part of the posterolateral corner of the knee, in conjunction with tendons (biceps femoris, popliteus) and other ligaments (PCL, popliteofibular ligament). Injuries to the Posterolateral corner can result in side to side and/or rotational instability.

How is an LCL injury investigated?

An Xray is often performed when a significant knee injury occurs. It may show a fracture avulsion from the fibula head. An ultrasound is not required.

Either your GP or your surgeon at Melbourne Hip and Knee will organise for you to have an MRI. This helps show where the LCL is injured (at the femur, in the middle of the ligament (mid-substance) or at the fibula). An MRI will also help look at any other injuries that may have occurred, such as damage to other structures of the posterolateral corner or an ACL injury or meniscal tear

What injuries can be associated with an LCL injury?

An LCL injury can be associated with injuries to the posterolateral corner of the knee or other ligaments in the knee (ACL, PCL, MCL) as part of a multi-ligament injury. Chondral and meniscal injuries can also occur.

How is an LCL injury treated?

The majority of LCL sprains are treated non-operatively. Initial management of the injury consists of RICE (Rest, ice, compression and elevation). This will help decrease the swelling and pain associated with the injury. Ones the pain settles down, you can weight bear as tolerated. A rehabilitation and strengthening protocol is then instituted with a physiotherapist to improve the range of motion and stability of the knee.


Grade 1 and some Grade 2 sprains may benefit from a simple off the shelf brace from the pharmacy, that offers some support but may help decrease swelling aide range of motion.

A special brace, called a hinged-knee brace, is used for the non-operative treatment of more severe sprains (Grade 2 and Grade 3). It is a brace that offers external side to side support for the knee while allowing the ligament to heal. The brace can also be set to restrict certain degrees of bending to again help the ligament heal.

The brace is worn for a period of 6 weeks and then the stability of the knee is re-assessed to allow further progression through the rehabilitation process.

Physiotherapy and the use of a hinged knee brace is also required in the event Lateral Collateral Ligament Surgery is required.