The posterolateral corner (PLC) of the knee consists of several stabilizing structures that protect the knee against direct varus and rotational forces. The three main stabilizers are the lateral (fibular) collateral ligament (LCL), popliteofibular ligament (PFL), and popliteus tendon. Secondary stabilizers include the lateral capsule, hamstrings, and IT band.
PLC injuries commonly occur from a direct blow to the anteromedial knee or forced hyperextension. They are often associated with anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) tears.
What Is a Posterolateral Corner Injury?
A posterolateral corner injury involves damage to one or more structures that stabilize the back and outside of the knee against varus and rotational forces.
The main stabilizers of the posterolateral corner include:
- Lateral (fibular) collateral ligament (LCL)
- Popliteofibular ligament (PFL)
- Popliteus tendon
The lateral capsule, hamstrings, and IT band also assist with stability.
PLC injuries are often found along with ACL and PCL tears, making evaluation of the posterolateral corner important following ligament injuries.
Causes and Risk Factors
Posterolateral corner injuries occur when a force exceeds the strength of the stabilizing structures. Causes may include:
- A direct blow to the knee, particularly the anteromedial knee
- Forced hyperextension
- Non-contact injuries
PLC injuries also commonly occur along with ACL and PCL tears.
Risk factors include:
- Contact sports that may result in forced hyperextension of the knee, including football, volleyball, basketball, soccer, and rugby
- Poor physical conditioning, including strength and flexibility
Symptoms
Signs and symptoms may include:
- A pop heard or felt at the time of injury
- Inability to continue activity after the injury
- Significant knee swelling within six to eight hours after injury
- Inability to straighten the knee
- Walking with a limp
- Giving way or buckling of the knee, particularly during the first several months after injury
- Occasional locking when there is an associated meniscus injury
- Pain that worsens with prolonged sitting, rising from a seated position, going up or down stairs or hills, kneeling, squatting, or wearing shoes with heels
- Pain with jumping
- Achy pain that may sometimes be sharp
- Difficulty running backward or backpedaling
- Foot drop if the peroneal nerve is damaged
Treatment
Initial treatment includes medications and ice to relieve pain and reduce knee swelling. Walking with crutches is often recommended. Bracing or casting may also be recommended initially.
Rehabilitation usually focuses on:
- Reducing knee swelling
- Regaining knee range of motion
- Regaining muscle control and strength
- Functional training
- Bracing
- Education, including avoiding sports and activities that require pivoting, cutting, changing direction, jumping, and landing
Properly timed surgical repair or reconstruction of one or more injured structures may be required to restore knee stability.
Nonsteroidal anti-inflammatory medications such as aspirin and ibuprofen, or other minor pain relievers such as acetaminophen, are often recommended as directed by a physician. Stronger pain relievers may be prescribed when necessary.
Cold can be used to relieve pain and reduce inflammation. It may be applied for 10 to 15 minutes every two to three hours and immediately after activities that aggravate symptoms. Heat may be used before stretching and strengthening activities prescribed by a physician, physical therapist, or athletic trainer.
Recovery and Outcomes
If untreated, a posterolateral corner injury usually results in the knee giving way and recurrent knee injuries during sports and often during daily activities.
Injuries involving the arteries or nerves have a higher risk of a poor outcome. Surgery is often required to restore knee stability.
Some athletes do not return to sports after this injury. The prognosis is better when there is no injury to the arteries or nerves, and return to sports often depends on associated injuries and the demands of the sport.
When to See Dr. Chudik
Contact Dr. Chudik’s office if symptoms worsen following a posterolateral corner injury. Because these injuries may involve knee instability as well as nerve or blood vessel injury, evaluation of knee stability and nerve and vascular function is important.
Call 630-324-0402, request an appointment online, or email contactus@chudikmd.com.