Lateral Knee Ligament Sprain (LCL)

Lateral knee ligament sprain

A lateral ligament sprain is a knee injury involving a tear to the ligament on the outside of the knee. It most commonly occurs following a direct blow to the inside of the knee. However, it can develop gradually through overuse.

Symptoms of an LCL sprain

  • The main symptoms of a lateral collateral ligament sprain (LCL sprain) is pain on the outside of the knee.
  • Pain can vary from being very mild to a complete rupture of the ligament.
  • You may have swelling over the outside of the joint.

Lateral ligament sprains are categorized into grade 1, grade 2 or grade 3 sprains, depending on the extent of your injury.

Grade 1

Grade 1 lateral ligament sprain symptoms include tenderness on the outside of the knee over the ligament. Usually, there will be little or no swelling. When the knee is bent to 30 degrees and force applied to the inside of the knee which puts the ligament under stress, pain is felt but there is no joint laxity. This is known as the varus stress test.

Grade 2

With a grade 2 LCL sprain, you will have significant tenderness on the outside of your knee, over the lateral ligament. You will likely have some swelling. A varus stress test will indicate pain and some laxity in your joint, although there is a definite endpoint indicating the ligament is still intact.

Grade 3

A grade 3 lateral ligament sprain is a complete tear of the ligament. Pain can vary and may be actually less than a grade 2 sprain. When stressing the knee there is significant joint laxity and you may have a very unstable knee.

Varus stress test

The varus stress test is used to help diagnose injury to the lateral knee ligament by putting it under stress or tension. The therapist takes hold of the limb, ensuring the knee is slightly bent (approx 30 degrees). They stabilize the thigh whilst applying inward pressure on the lower leg.

This stretches the lateral ligament. Pain on the outside of the knee indicates a positive test. The degree of damage can be determined by how much movement/instability is present.

Causes & anatomy

LCL sprain anatomy

The lateral ligament or lateral collateral ligament or LCL for short connects the femur or thigh bone to the top of the fibula bone in the lower leg. The ligament itself is a narrow strong cord of collagen fibres and its function is to provide stability to the outside of the knee.

The LCL is most commonly injured in sports by a direct impact to the inner surface of the knee joint, such as by a rugby or a football tackle. A lateral ligament sprain is less common than those affecting the medial collateral ligament which commonly occurs as a result of trauma to the outside of the knee.

The ligament is not connected to the lateral meniscus in the joint and so unlike medial ligament injuries, they are not normally associated with meniscal tears. However, injury to the anterior cruciate ligament or posterior cruciate ligaments can occur at the same time as a lateral ligament sprain. A full examination once any pain and swelling have gone down is required.


Treatment is similar for all knee ligament injuries.

What can the athlete do?

  • Immediately following an acute injury, or if there is swelling apply the PRICE principles (Protection, Rest, Ice, Compression, Elevation).
  • Rest may mean complete rest or for a longer-term, chronic injuries discontinue the sport or activity that irritates the injury or causes pain.
  • Wear a hinged knee brace to support and protect the joint, particularly for grade 2 and 3 injuries. A hinged knee brace will have solid metal supports at the sides to protect the knee from a lateral (sideways) movement which would stress the lateral knee ligament.

What can a sports injury professional do?

Lateral knee ligament sprain taping
  • The initial aim of a health professional will be to assess the extent of the injury and obtain an accurate diagnosis.
  • In more serious cases an MRI scan and/or X-Ray may be necessary.
  • Depending on the severity of the injury a number of treatment options are presented to the clinician.
  • In grade 1 & 2 tears, conservative methods of treatment are usually preferred. These may need to be carried out for up to 8 weeks and may include ultrasound or laser treatment, prescription of NSAID’s (e.g. Ibuprofen).
  • They may use manual techniques, such as massage and prescribe on a full rehabilitation program, which includes strengthening and proprioceptive and balance exercises.
  • They may use lateral knee ligament strapping and taping to protect and support your knee whilst it is healing.

Sports massage

MCL massage

Sports massage may help the healing of a lateral ligament injury when applied directly to the ligament in the form of cross friction massage. This may help to reduce scar tissue formation and re-align the new healing fibers with the ligament. Before starting any massage treatment the therapist will check for contraindications (if any apply to you, then massage is not allowed).

Cross friction massage must not be performed during the acute stage of this injury – usually 48-72 hours after injury. For grade two and three strains, massage may not be suitable for over a week. This is because if the is still bleeding then heat and massage will increase bleeding, not stop it. Sports massage techniques can also be applied to the quadriceps and hamstring muscles in order to reduce swelling and relax tight muscles to improve flexibility.

Aim to gradually apply firmer frictions to reduce adhesions and aid healing. With a finger, apply frictions backward and forwards across the ligament as shown opposite. The therapist may apply frictions to the ligament at the point of the joint line, trying to identify specifically the injured area by feeling and judging the response from the athlete. Start gently and slightly away from the tendon attachment, gradually working towards the attachment and getting deeper as the athlete becomes accustomed to massage.

Read more: LCL sprain rehabilitation program


In grade 3 sprains, particularly when other structures such as an ACL tear or PCL tear are damaged, surgery may be needed to prevent future instability. This may involve suturing or stitching the torn ends of the LCL or reconstructing the ligament with a part of a tendon e.g. hamstrings tendon.

Recovery from these injuries is a lot slower than conservative methods and it may be a number of months before the athlete is able to return to sports.

LCL sprain exercises & rehabilitation

Hopping plyometric exercises

Exercises for rehabilitation of lateral knee ligament sprains should include mobility, stretching, strengthening, proprioception and eventually sports specific exercises. Initially, isometric or static strengthening exercises are done. These progress to dynamic knee exercises involving movement. Proprioception exercises involve balance and co-ordination.

Read more on LCL sprain exercises.

References & research

  • LaPrade RF, Wentorf FA, Fritts H et al. A prospective magnetic resonance imaging study of the incidence of posterolateral and multiple ligament injuries in acute knee injuries presenting with a hemarthrosis. Arthroscopy 2007;23(12):1341–7

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