The posterolateral corner is the region on the outer aspect of the knee, towards the back. The anatomy here is complex, and repair of any damage is the domain of only the expert surgeon.

Page updated October 2023 by Dr Sheila Strover (Clinical Editor)

postero-lateral corner of the knee


This illustration shows the back of the right knee, deep to the hamstrings muscles.

posterolateral corner from above

Looking down at the two menisci from above, you can see the tendon of the popliteus muscle passing between meniscus and capsule at the posterolateral corner.



What structures make up the posterolateral corner?

One of the key structures of the posterolateral corner is the popliteus muscle and its tendon. The muscle arises on the tibia bone and wraps around the back of the tibia to attach via its tendon on the outer aspect of the femur at the side of the knee joint. The popliteus tendon has an intimate relationship to the back of the lateral meniscus.

Related to the popliteus muscle and tendon is the popliteofibular ligament. It arises on the fibula bone and then merges with the popliteus tendon. It is an important knee stabiliser.

Where the popliteus tendon passes into the joint space itself the capsule is weakened. This means that injuries in this region - the posterolateral corner - often involve the capsule as well as the tendon and ligament. That part of the capsule that loops over the popliteus tendon is referred to as the arcuate ligament.

Another important structure of the postero-lateral corner is the lateral collateral ligament (also called the fibular collateral ligament). This spans the outside of the joint from the fibula bone to the femur, and is an important stabilising structure. It is outside the capsule - when the surgeon looks into the joint from the front during arthroscopy the camera is within the capsule, so the surgeon will not be able to see during arthroscopy if it is broken.

The surgeon is normally able to see the popliteus tendon as it passes inside the joint. If it is ruptured a careful surgeon should be able to see this during arthroscopy, and should at least note the absence of the tendon at the back of the lateral meniscus.

Other important postero-lateral corner structures include the:


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What are the symptoms of a posterolateral corner injury?

Damage to the posterolateral corner may lead to instability, with the knee joint thrusting outwards with each step (lateral thrust).

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What is the usual mechanism of injury of the posterolateral corner?


hyperextension injury

Injury to the posterolateral corner is usually the result of an impact, especially if the knee is hyper-extended (bent backwards).

In this 'pothole' example there is no impact, but momentum carries the person forward and the person's foot cannot follow, leading to knee hyperextension.

Usually there is an associated injury to the anterior or posterior cruciate ligament (ACL or PCL). In that case, repair of these two ligament injuries may fail unless the surgeon also addresses damage to other posterolateral corner structures.

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Why is reconstruction of the posterolateral corner so challenging?

  1. This region of the knee is inherently unstable. When PLC damage is associate with cruciate ligament tears, failure to stabilise the PLC may lead to failure of the cruciate ligament reconstruction
  2. The full diagnosis may only have been appreciated months after the injury and often long after cruciate ligament reconstruction.
  3. The anatomy is challenging. For example the popliteus muscle is outside the joint capsule but its tendon attaches within the joint capsule.
  4. In challenging cases stability may be improved with a slope-changing osteotomy.

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Forum discussions

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Peer-reviewed papers

  • Injuries to posterolateral corner of the knee: a comprehensive review from anatomy to surgical treatment

    Citation: Crespo B, James EW, Metsavaht L, LaPrade RF. Injuries to posterolateral corner of the knee: a comprehensive review from anatomy to surgical treatment. Rev Bras Ortop. 2014 Dec 24;50(4):363-70. doi: 10.1016/j.rboe.2014.12.008. PMID: 26401495; PMCID: PMC4563052.


    "...present in almost 16% of all knee injuries and are responsible for sustained instability and failure of concomitant reconstructions if not properly recognized."

  • Posterolateral corner knee injuries: a narrative review

    Citation: Figueroa F, Figueroa D, Putnis S, Guiloff R, Caro P, Espregueira-Mendes J. Posterolateral corner knee injuries: a narrative review. EFORT Open Rev. 2021 Aug 10;6(8):676-685. doi: 10.1302/2058-5241.6.200096. PMID: 34532075; PMCID: PMC8419800.


    "...the PLC (is) often...labelled as the ‘dark side’ of the knee...a standardized algorithm for the diagnosis and treatment of the PLC is still lacking, and much controversy remains...Treatment decisions should be made on a case-by-case basis."

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