The Posterior-Lateral Corner (PLC) is a part of the knee joint that is located at the outside (lateral) back (posterior) of the knee, comprising of many ligaments, tendons, and soft tissues. These structures overlap to attach to various structures, and help to maintain the static and dynamic stability of the posterior lateral knee. They help in preventing too much rotational and sideways movement at the knee, as well as protect from over extending the knee.
The various structures in the PLC are the popliteus tendon, popliteofibular ligament, lateral collateral ligament, posterolateral joint capsule, oblique popliteal ligament, popliteus muscle, illiotibial band, biceps femoris, and the lateral gastrocnemius tendon.
Posterolateral force directed to the inside of the Knee, Knee hyperextension, or excessive knee rotation when the Knee is on the ground and partially bent are the causes of injury to the PLC. They frequently occur with other ligament injuries, such as an Anterior Cruciate Ligament Tear or Posterior Cruciate Ligament Tear.
Patients often complain of knee joint pain and instability at the joint. Bruising over the outer aspect of thigh may also be seen.
This is performed with the hip flexed 45°, Knee flexed 80°, and foot is ER 15°. A combined posterior drawer and external rotation force is then applied to the knee to assess for an increase in Posterolateral translation (lateral tibia externally rotates elative to lateral femoral condyle).
This is usually done in isolated Posterior-Lateral Corner Grade I or II injuries. This is usually followed by progressive functional rehabilitation focusing on quad strengthening with return to sports in 8 weeks.
This can be done only when there is an acute (within 2 weeks) and isolated injury of the Posterior-Lateral Corner with bony or soft tissue avulsion.
It is done for most Grade III isolated injuries as well as Multiligament injuries.
The goal is to reconstruct LCL and the popliteofibular ligament using a free tendon graft (semitendinosus or achilles).
There are two types of reconstruction techniques as follows :
Fibular-based reconstruction (Larson)
In this the hamstring graft passed through bone tunnel in fibular head and the two limbs of the graft are crossed to create figure-of-eight and fixed to lateral femur.
Split achilles tendon is fixed to isometric point of the femoral epicondyle.
One limb is fixed to the fibular head with a bone tunnel and transosseous sutures to reconstruct the LCL.
The second limb is brought through the posterior tibia to reconstruct the popliteofibular ligament.