Anterior Cruciate Ligament

  • ACL Function
    • Provides 85% of the stability to prevent anterior translation of the tibia relative to the femur.
    • Acts as secondary restraint to tibial rotation and varus/valgus rotation.
  • ACL Anatomy
    • 33mm x 11mm in size.
    • Goes from Lateral femoral condyle to anterior tibia (Tibial insertion is broad and irregular and inserts just anterior and between the intercondylar eminences of the tibia).
    • Two bundles
      • Anteromedial bundle
        • More isometric
        • Tight in flexion
      • Posterolateral bundle
        • Tightest in extension (where it likely contributes greatest to rotational stability)
  • ACL Blood supply
    • Mainly from Middle geniculate artery
  • ACL Innervation
    • Posterior articular nerve (branch of tibial nerve)
  • ACL Composition
    • 90% Type I collagen
    • 10% Type III collagen
  • ACL Strength: 2200 N (anterior)




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