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Medial Collateral Ligament Injury

  • Primary restraint to valgus stress; especially in flexion
  • ACL and posterior oblique ligament (POL) contribute in extension
  • The most common site of injury is femoral insertion of the ligament


  • Superficial layer (tibial collateral ligament) : from medial condyle, just below the adductor tubercle to medial subcutaneous surface of the tibia, 6 - 7 cm below the joint line behind the axis of rotation
  • Deep layer : Condensation in the medial joint capsule from the medial epicondyle of the femur to the medial meniscus and via the coronary ligament to the tibia


  • History of valgus force
  • May accompany medial meniscus and ACL tear (O'Donaghue triad)
  • Patterns of valgus instability
    • Laxity in 30° flexion : MCL tear
    • Laxity in full extension : MCL + ACL + POL
    • Laxity in hyperextension : MCL + ACL + POL + PCL
  • Significance :
    • Grade 0 : sprain; tenderness confined to medial femoral epicondyle
    • Grade I : superficial MCL tear
    • Grade II : superficial and deep MCL tear
    • Grade III : Complete MCL + ACL tear; no end point
  • Tenderness at the site of injury
  • Palpable defect may be present


  • X-Ray
    • Rarely, may show an avulsion fracture at medial epicondyle
    • Shows calcification at femoral insertion site in chronic cases (Pellegrinni-Steida sign)
    • Helpful in differentiating epiphyseal injury from MCL tear in premature patients
  • MRI shows accompanying meniscus / ACL injuries


  • Healing of mid-substance tear is not improved by surgery
  • Bony avulsions respond well to reattachment
  • Isolated MCL injury : bracing ± early motion, depending on the severity of the injury ** Grade I / II : early ROM, return to full activity at 2 - 6 weeks
    • Grade III : locked brace at 30° for 2 weeks, ROM inside brace for 4 more weeks
  • If MCL injury is associated with another major ligamentous injury; e.g. ACL/PCL, surgery is indicated for repair / reconstruction of the ACL/PCL
    • Some advocate treatment of the MCL only if there is residual 3+ medial instability after ACL reconstruction
    • Those with 3+ medial instability usually have an accompanying postero-medial disruption which should be addressed with repair of the POL and semi-membranous insertion
    • Best to postpone ACL surgery until :
      • MCL has healed conservatively
      • Inflammation subsided
      • 90° ROM obtained
  • Chronic MCL rupture
    • Usually responds to brief immobilisation
    • Rarely requires surgical ligament augmentation / advancement


  • Pitman M.I., Luks H.J. : Knee collateral ligament injury. In Spivak JM, Di Cesare PE, Feldman DS : Orthopedics; A Study Guide; 1999
  • Baumfeld J.A., Hart J.A. and Miller M.D. : Sport medicine. In Mark D. Miller : Review of Orthopedics; 2008
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