Medial Collateral Ligament

Reviewed by

Dr Sam Joseph
MBBS | Accredited Orthopaedic Registrar

Anatomy

  • origin
    • 1cm anterior and distal to the adductor tubercle
  • insertion
    • anterior parallel fibres run to the anteromedial tibial crest 4.5cm distal to the MJL blend with the periosteum posterior to the pes anserinus
  • Layers (Warren and Marshall 3 layer concept)
    • Layer 1 – superficial layer
      • A continuation of the deep fascia of the thigh
      • Details
        • fascial layer covering Sartorius, extends posteriorly to cover Gastrocnemius & neurovascular structures of fossa
        • anteriorly it blends with layer II 2cm anterior to the sMCL
        • distally layer I joins the periosteum near the insertion of Sartorius
    • Layer II – middle layer
      • Superficial medial ligament from medial condyle just below the adductor tubercle to medial subcutaneous surface of the tibia 6 – 7cm below the joint line behind the axis of rotation
      • Details
        • sMCL, ligaments of the PMC, MPFL
        • at the PMC layer II blends with layer III to form the posteromedial capsule
        • the posteromedial capsule is joined by the tendon and sheath of the SM
        • SM has several insertion sites
          • into the posteromedial corner of the tibia just distal to the joint line
          • anteriorly insert deep to the sMCL
        • from the sheath; oblique popliteal ligament (inserts into LFC)
    • Layer III – Deep layer
      • Condensation in the medial joint capsule from the medial epicondyle of the femur to the medial meniscus & via the coronary ligament to the tibia
      • Details
        • true capsule of the knee joint
        • deep MCL is femoromeniscal and tibiomensical ligaments
        • dMCL; from the femur to the meniscus to the tibia
        • 2cm posterior to the sMCL layers II & III blend with the meniscofemoral portion of the dMCL
        • posteriorly layers blend with the tendon sheath of SM forming the posteromedial capsule
  • Bursae
    • bursa between the deep and superficial MCLs

Biomechanics of the MCL

  • Superficial MCL is the:
    • 1º restraint to valgus stress
    • 2º to ER & anterior translation
    • Transections
      • transection of sMCL = 2-5º of laxity
      • transection of sMCL + PM capsule = 7-10º of laxity
    • in flexion anterior fibres of sMCL are tight and the posterior fibres are lax
    • largest strain occurs with valgus load
    • the forces are concentrated at the femoral attachment – most commonly injured here
  • Deep MCL is a
    • secondary stabilizer to valgus stress

Aetiology

  • Valgus stress applied to a flexed knee
  • ER pivoting injury
  • blow to the anterolateral knee
  • knee dislocation
  • concomitant injuries (lig’s and menisci) up to 78% in GIII sprains

History

  •  valgus blow

Examination

  • thorough examination as concomitant injuries are common
  • haemarthrosis
    • ?meniscal/chondral/ligamentous
  • tenderness along course of MCL
  • MJL tenderness
    • ?MM
  • Valgus stress at 30º and at extension (POL + ACL) compare with uninjured side
GradeDescription
I<5mm
II5-10mm
III>10mm
American Medical Association – Joint line opening
DegreeDescription
1st degree spraintender no instability
2nd degree sprainincreased valgus laxity firm end point
3rd degree sprainno end point
Degree of Injury

Investigations

  • XR
    • Pellegrini-Stieda lesion – heterotopic calcification at the proximal origin
    • indicates a severe injury slubluxation/dislocation and may be symptomatic
    • injection or excision may lead to relief
  • MRI
    • T2 weighted
    • normally low signal
    • high signal, discontinuity or thickening
    • useful to detect concomittant injuries

Natural History of disruption

  • Healing of mid substance tear not improved by surgery
  • Bony avulsions respond well to reattachment

Treatment

Prophylactic

Prophylactic Knee Bracing

  • Controversial
  • Mechanically 20-30% strain relief with brace (Brown)
  • 1 prospective randomized study at West Point with cadets playing tackle football. >2x incidence of knee injuries if not wearing a brace
  • Perception that it compromises athletic performance

Nonoperative

  • isolated GI & GII
    • early motion ± bracing depending on the severity of the injury
      • early ROM & WBing
      • strengthening of quads & hamstrings
      • HKB allows early ROM while protecting knee from a valgus stress
  • isolated tears GIII
    • can be successfully managed nonsurgically provided there is no associated meniscal or ACL damage

Operative

  • Isolated MCL GIII
    • functional rehabilitation, if persistent laxity affecting function then surgical repair
  • MCL injury associated with another major ligamentous injury
    • e.g. ACL/PCL
      • however repair /reconstruction of the ACL or PCL may be all that is necessary
    • MCL + ACL tears
      • 1+ 2+ medial instability
        • treatment of the ACL only
        • brace for 6wks, ACL reconstruction then assess MCL if laxity intraoperatively repair
      • 3+ medial instability
        • likely to have posteromedial disruption
        • should be repaired with emphasis on repair of the posterior oblique ligament & semimembranosus insertion
    • MCL + ACL + PCL
      • brace 6wks, reconstruct ACL/PCL if laxity then intraoperatively repair MCL

References

  • Treatment of Medial Collateral Ligament Injuries, Ryan Miyamoto, Joseph Bosco, Orrin Sherman JAAOS 2009; 17:152-161

Victorian Orthopaedic Registrar presentation