Lateral Collateral Ligament and Posterolateral Corner Injury

3 Interesting Facts of Lateral Collateral Ligament and Posterolateral Corner Injury 

1. The lateral collateral ligament (LCL), or fibular collateral ligament (FCL), is the primary stabilizer against varus stress on the knee.
2. •The LCL originates on the lateral epicondyle of the femur and inserts on the fibular head.
3. •The posterolateral corner is composed of several ligaments on the outside of the knee, including the LCL, popliteofibular ligament (PFL), and popliteus tendon; combined, these ligaments resist varus stress and external rotation of the knee.

• The posterolateral corner is a static and dynamic stabilizer of the knee and provides secondary restraint for anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injuries.
• •Isolated LCL injuries are rare; therefore it is important to look for additional injuries to other ligaments.

History

• •Acute
  • •Varus force, hyperextension (contact or noncontact related)
  • •Patient feeling of side-to-side instability
• •Chronic
  • •Lateral or medial knee pain
  • •Instability on near extension, cutting exercises, or stair climbing
  • •Swelling following physical activity

Physical Examination

• •Presentation
  • •Swelling or abrasions following a medial force on the knee.
  • •Lateral knee pain.
  • •Deformity.
  • •Varus thrust gait may be present.
• •Palpation
  • •Tenderness over the lateral knee or fibular head.
  • •Swelling over lateral knee.
• •Range of Motion
  • •Swelling may limit extremes of flexion and extension.
  • •Locked knee (cannot fully extend) may indicate bucket-handle meniscal tear.
• •Special Tests
  • •Neurovascular Examination
    • •Evaluate for common peroneal nerve injury
    • •Foot drop or weak dorsiflexion
    • •Sensory changes on dorsal foot
    • •Tinel sign at fibular neck
    • •Evaluate distal pulses
  • •Knee Examination
    • •LCL: Varus stress testing at 30 degrees of flexion; if there is laxity in full extension, there is a grade III LCL injury with or without concomitant cruciate injury.

Popliteus tendon/popliteofibular ligament: Dial test with increased external rotation at 30 degrees of flexion; if it is also increased at 90 degrees of flexion, there is a combined posterolateral corner (PLC)/PCL injury

Reverse pivot shift: Valgus stress on the knee as it is taken from 90 degrees of flexion to full extension with the foot externally rotated; this may indicate posterolateral rotatory instability. This is often positive in normal knees with genu recurvatum, so check the contralateral knee.

•Assessment of varus thrust gait.

•ACL/PCL: Increased translation on Lachman’s and posterior drawer tests.

Imaging

• •Radiographs: Highly Recommended
  • •Anteroposterior and lateral views: Check for avulsion fracture of fibular head.
  • •Posteroanterior flexion weight-bearing view: Degenerative changes, especially in the medial compartment.
  • •Look for degenerative changes on patellofemoral views.
  • •Bilateral varus stress views: >2.7 mm of increased gapping is seen with LCL tear, >4.0 mm of gapping is seen with a complete PLC tear 

Magnetic Resonance Imaging (MRI): Highly Recommended

• •Look for disruption of LCL on coronal views
  • Popliteus tendon/PFL is more difficult to image but is also typically seen on coronal views.
  • •Look for bone bruising in the medial femoral condyle and medial tibial plateau.
  • •Evaluate for concomitant injuries (ACL, PCL, meniscal tears).

Differential Diagnosis

• •Lateral meniscus tear
• •Multiligamentous knee injury
• •Bone bruise
• •Knee dislocation/multiligament damage
• •Medial compartment arthritis with medial compartment pseudolaxity

Treatment

• •Acute
  • •RICE: rest, ice, compression, elevation
  • •Knee immobilization in extension or slight flexion
  • •Toe touch or partial weight bearing for 2 to 4 weeks followed by progressive rehabilitation for grade I and grade II injuries
  • •Surgical intervention for grade III injuries
  • •Surgical reconstruction should be performed within 3 weeks of injury
• •Chronic
  • •Surgical reconstruction is necessary.
  • •Bracing can be beneficial (medial compartment unloaders).
  • •Osteotomies are necessary when varus alignment is present.

When to Refer

• •Grade III injuries should be referred immediately because optimal outcomes are obtained for surgery within 3 weeks. In more chronic cases, reconstructive procedures are necessary.
• •Vascular injury is an emergent condition.
• •Common peroneal (fibular) nerve involvement.
• •Combined ligamentous injuries.
• •Chronically unstable knee.
• •Patients with varus alignment and chronic injuries.
• •Avulsion fractures may be amenable to reduction and fixation and should be referred as soon as possible.

Prognosis

• •Isolated grade I/II: often heal without surgical intervention

• Grade III: often require surgical reconstruction; lack of reconstruction can lead to chronic knee instability.
• •Complete LCL ruptures or combined ligamentous injuries require surgical intervention; if untreated, these injuries can lead to chronic instability.
• •The increase in risk of osteoarthritis after these injuries is unknown.

Troubleshooting

• •The presence of degenerative changes or malalignment may complicate recovery.
• •Physeal injuries in the skeletally immature patient may present similarly to ligamentous injuries.
• •These injuries can become chronically disabling if not addressed appropriately.

Instructions for the Patient

• •Avoid heat in the acute phase.
• •Wear brace during weight-bearing activities for 2 to 4 weeks for partial tears.
• •Report any giving way or instability
• •Seek medical attention with signs of deep venous thrombosis or vascular compromise.

Considerations in Special Populations

• •High-level athletes warrant referral to determine return to sport activities.

Suggested Readings

1. Arthur A, LaPrade RF, Agel J: Proximal tibial opening wedge osteotomy as the initial treatment for chronic posterolateral corner deficiency in the varus knee: a prospective clinical study. Am J Sports Med 2007; 35 (11): pp. 1844-1850.
2. Geeslin AG, LaPrade RF: Location of bone bruises and other osseous injuries associated with acute grade III isolated and combined posterolateral knee injuries. Am J Sports Med 2010; 38 (12): pp. 2502-2508.
3. Geeslin AG, Moulton SG, LaPrade RF: A systematic review of the outcomes of posterolateral corner knee injuries, part 1: surgical treatment of acute injuries. Am J Sports Med 2016; 44 (5): pp. 1336-1342.
4. LaPrade RF: Arthroscopic evaluation of the lateral compartment of knees with grade 3 posterolateral knee complex injuries. Am J Sports Med 1997; 25 (5): pp. 596-602.
5. LaPrade RF, Gilbert TJ, Bollom TS, et al.: The magnetic resonance imaging appearance of individual structures of the posterolateral knee. A prospective study of normal knees and knees with surgically verified grade III injuries. Am J Sports Med 2000; 28 (2): pp. 191-199.
6. LaPrade RF, Heikes C, Bakker AJ, Jakobsen RB: The reproducibility and repeatability of varus stress radiographs in the assessment of isolated FCL and grade-III posterolateral knee injuries. An in vitro biomechanical study. J Bone Joint Surg Am 2008; 90 (10): pp. 2069-2076.
7. LaPrade RF, Johansen S, Agel J, et al.: Outcomes of an anatomic posterolateral knee reconstruction. J Bone Joint Surg Am 2010; 92 (1): pp. 16-22.
8. LaPrade RF, Johansen S, Wentorf FA, et al.: An analysis of an anatomical posterolateral knee reconstruction: an in vitro biomechanical study and development of a surgical technique. Am J Sports Med 2004; 32 (6): pp. 1405-1414.
9. LaPrade RF, Muench C, Wentorf F, Lewis JL: The effect of injury to the posterolateral structures of the knee on force in a posterior cruciate ligament graft: a biomechanical study. Am J Sports Med 2002; 30 (2): pp. 233-238.
10. LaPrade RF, Resig S, Wentorf F, Lewis JL: The effects of grade III posterolateral knee complex injuries on anterior cruciate ligament graft force. A biomechanical analysis. Am J Sports Med 1999; 27 (4): pp. 469-475.
11. LaPrade RF, Spiridonov SI, Coobs BR, et al.: Fibular collateral ligament anatomical reconstructions: a prospective outcomes study. Am J Sports Med 2010; 38 (10): pp. 2005-2011.
12. LaPrade RF, Terry GC: Injuries to the posterolateral aspect of the knee: association of anatomic injury patterns with clinical instability. Am J Sports Med 1997; 25: pp. 433-438.
13. LaPrade RF, Wentorf F: Acute knee injuries: on-the-field and sideline evaluation. Phys Sportsmed 1999; 27 (10): pp. 55-61.
14. LaPrade RF, Wentorf F: Diagnosis and treatment of posterolateral knee injuries. Clin Orthop Relat Res 2002; 402: pp. 110-121.
15. Long JL, Miller BS: Lateral collateral ligament and posterolateral corner injury. In Miller MD, Hart JA, MacKnight JM (eds): Essential Orthopaedics., 1st ed 2009. Elsevier, Philadelphia pp. 624-627.
16. Moulton SG, Geeslin AG, LaPrade RF: A systematic review of the outcomes of posterolateral corner knee injuries, part 2: surgical treatment of chronic injuries. Am J Sports Med 2016; 44 (6): pp. 1616-1623.
17. Moulton SG, Matheny LM, James EW, LaPrade RF: Outcomes following anatomic fibular (lateral) collateral ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 2015; 23 (10): pp. 2960-2966.
18. Terry GC, LaPrade RF: The posterolateral aspect of the knee. Anatomy and surgical approach. Am J Sports Med 1996; 24 (6): pp. 732-739.