Posterolateral Corner Injury
Article by John Miller
What is a Posterolateral Corner Injury?
Injuries to the posterolateral corner of the knee (PLC for short) are most commonly associated with athletic traumas, motor vehicle accidents and falls. PLC injuries account for 16% of all knee ligament injuries and often occur in combination with other cruciate ligament injuries.
PLC provides both static and dynamic stabilisation to the knee joint. The static structures include the lateral collateral ligament (LCL or FCL), popliteus tendon, the popliteofibular ligament and the posterolateral capsule. Together these structures prevent varus collapse at the knee and external rotation of the tibia on the femur. Dynamic structures of the PLC play similar roles as the static structures but through movement. These structures include the popliteus muscle, iliotibial band, bicep femoris and the lateral gastroc tendon.
Your PLC is the area on the outside of your knee that extends from the bottom of your femur (thigh bone) to the heads of the tibia and fibula (lower leg bones) immediately below the outside of your knee.
Ligaments and joint capsules surrounding the joint offer more stability during movement and weight bearing.
Importantly, the common peroneal nerve (a nerve that supplies the lower leg and toes) wraps around the top of the fibula and can also be implicated if there is an injury to the PLC of the knee.
What Causes a Posterolateral Corner Injury?
The posterolateral corner of the knee is most commonly injured following a combined hyperextension and varus force to the knee. An example of how this could be sustained would be a posteromedial angled blow to the extended leg. Other mechanisms include coupled hyperextension and external rotation of the tibia or external rotation of the tibia and a heavy varus force.
What are the Symptoms of a PLC Injury?
Injuries affecting the PLC may or may not occur in conjunction with injuries to other structures in the knee. Symptoms of a PLC injury commonly include:
If you have an injury to the PLC and the peroneal nerve is affected, you may also experience pins and needles and/or numbness in the lower leg and foot. You may also experience foot or ankle weakness.
How is a Posterolateral Corner Injury Diagnosed?
On examination, your physiotherapist or sports doctor will look for signs of a PLC injury. Palpation and a series of knee ligament stability tests on physical examination will be utilised to confirm or deny injury to the PLC and will be graded accordingly based on severity. An MRI may be required to confirm the diagnosis.
What is the Treatment for a PLC Injury?
Most patients with a mild posterolateral injury start to recover within a few weeks of the injury with the appropriate rehabilitation.
Your physiotherapy treatment will aim to:
We advise that you discuss your knee injury with a knee injury practitioner such as a sports physiotherapist, sports physician or knee surgeon. This will provide you with the most accurate information regarding your specific injury and rehabilitation program.
Most grade I PLC injuries resolve completely with conservative treatment. In severe cases, and depending on the number of structures within the PLC involved, surgery may be required. Risks of surgery include infection, persistent instability and pain, stiffness, and difficulty returning to previous level of activity. Surgery is determined case by case and severity of the injury.
Functional instability is a problem with PLC injuries. Your return to sport should be professionally guided by your sports physiotherapist, sports doctor and/or knee surgeon.
Post-operative knee rehabilitation is one of the most important, yet too often neglected aspects of knee surgery. The most successful and quickest outcomes result from the guidance and supervision of an experienced physiotherapist.
Your rehabilitation following knee surgery focuses on restoring full knee motion, strength, power and endurance. You will also require balance, proprioception and agility retraining that is individualised towards your specific sporting or functional needs.
Your physiotherapist has extensive knowledge in this field. We suggest you contact them for the best advice in your circumstances.
How to Prevent a Posterolateral Corner Injury?
There are a number of things you can do to reduce your risk of sustaining a PLC injury.
Return to Sports with a PLC Injury
If a suitable rehabilitation regime is not undertaken, athletes often experience difficulty when returning to sport after sustaining a PLC injury. It is important to complete your specialised rehabilitation program as prescribed by your physiotherapist in order to return to sport as quickly and safely as possible.
Where to from here?
If you require more information or are interested in discussing your PLC injury please don’t hesitate to contact us:
Posterolateral Corner Injury Treatment Options
FAQs about Posterolateral Corner Injury
Helpful Products for Posterolateral Corner Injury
Knee Ligament Injuries
Children's Knee Conditions
Other Knee-Related Conditions
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