What is a posterolateral corner injury?
A posterolateral corner (PLC) injury involves damage to the joint lining, ligaments and tendons outside of the knee.
The PLC is made up of the following structures:
- Posterolateral capsule (lining of the joint)
- Lateral collateral ligament
- Iliotibial band
- Popliteus tendon
- Popliteofibular ligament
- Biceps femoris tendon (hamstring)
- Lateral head of the gastrocnemius muscle (calf)
An injury to more than one of these structures is defined as a PLC injury. These injuries can occur in conjunction with other knee injuries such as ACL and PCL tears.
This injury can be detected on clinical examination and will be investigated with an MRI scan. Occasionally, stress X-rays will be organised to assess the degree of instability.
What are the symptoms of a posterolateral corner injury?
PLC injuries can result in abnormal opening of the outside of the knee joint. As the PLC is important in controlling the rotation of the tibia on the femur, patients may notice difficulties with twisting, turning and pivoting.
The mechanism required to sustain this injury can occasionally cause stretching of the common peroneal nerve, which lies on the outside of the knee. This may cause weakness of the muscles controlling the ankle and lead to a foot drop. It may also cause changes to the sensation in the foot.
How do you treat a posterolateral corner injury?
Non-surgical management can be started if the structures of the PLC are sprained with no signs of instability found on clinical examination. This will usually involve a period of bracing and rehabilitation in conjunction with a physiotherapist.
If there are signs of instability on clinical examination, the PLC may require surgical repair.
What does surgery for a posterolateral corner injury involve?
If required, surgery for this injury is best performed early. The torn structures are repaired back in place using sutures via an open incision on the outside of the knee.
Following this, a graft (usually the hamstrings) is taken to augment the repair. This protects the repair and decreases the chances of stretching over time.
If there are injuries to other ligaments in the knee, these may be attended to during the same surgery.
Next step
Have your knee assessed
If the outside of your knee feels unstable, surgery is usually done semi-urgently. Dr Vishal Pai can examine your knee, review your scans and explain your options.