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  • LCL sprain

  • 844.0 Sprain of lateral collateral ligament of knee

  • S83.429A Sprain of lateral collateral ligament of unspecified knee, initial encounter


  • Tear of the lateral collateral ligament of the knee
  • Graded based on extent of damage
    • Grade I: localized tenderness with no instability
    • Grade II: localized tenderness, moderate fiber disruption, slight to moderate abnormal motion
    • Grade III: complete fiber disruption, noted instability

Essentials of Diagnosis

  • Injury is generally traumatic, can occur at any age; trauma usually a high-impact force applied to the medial knee
  • Clinical diagnosis generally made through history of injury and knee varus stability testing
  • Diagnosis may be confirmed with MRI

General Considerations

  • Lateral collateral ligament is most taut in extended knee position


  • Injury to lateral collateral ligament less common than to medial collateral
  • Most common in young athletic population

Signs and Symptoms

  • Lateral knee pain
  • Pain with palpation over lateral knee
  • Pain with varus force to knee
  • Pain with extension
  • Feeling of instability or “giving way” in the knee

Functional Implications

  • Pain with swinging legs in/out of car or bed
  • Decreased stability while walking on uneven surfaces
  • Decreased stability with change of direction

Possible Contributing Causes

  • Usually related to traumatic varus stress applied to the knee
    • Sports injury
    • Motor vehicle accident
  • May be related to severe, degenerative osteoarthrosis

Differential Diagnosis

  • Joint-line pain related to knee osteoarthrosis
  • Iliotibial band syndrome
  • Biceps femoris tendinopathy or strain
  • Arcuate-popliteal complex
  • Anterior cruciate ligament sprain or tear
  • Posterior cruciate ligament sprain or tear
  • Proximal tibiofibular joint pathology
  • Referred pain to hip, low back, sacroiliac joint

Laboratory Tests

  • Knee varus stress test in 30˚ knee flexion
  • Grading of laxity2
    • 1+ = 3-5 mm laxity
    • 2+ = 6-10 mm laxity
    • 3+ = greater than 10 mm laxity


  • MRI
  • Valgus stress radiograph3
    • Isolated injury of LCL
      • Increased lateral joint gap of 2.7 mm
    • Grade-III posterolateral corner injury
      • Increased lateral joint gap of 4.0 mm

  • Pain, tenderness, swelling in lateral knee from tissue disruption and inflammatory process
  • Possible laxity with varus force to knee, depending on extent of tissue disruption
  • Reports of “giving way” or instability with walking due to decreased lateral stability of the knee

  • To physician for pain management
  • To hospital for MRI if questionable diagnosis or if meniscus injury or tibial plateau fracture suspected
  • To physician, orthotist or physical therapist ...

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