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Anterior cruciate ligament injury

Last reviewed: 28 Oct 2023
Last updated: 28 Feb 2023



History and exam

Key diagnostic factors

  • audible pop
  • rapid knee swelling
  • inability to return to the ongoing sporting activity
  • sensation of knee instability or buckling
  • pain
  • positive Lachman test
  • positive pivot shift maneuver
More key diagnostic factors

Other diagnostic factors

  • tenderness at lateral femoral condyle, lateral tibial plateau
  • positive anterior drawer test
Other diagnostic factors

Risk factors

  • acute trauma
  • female sex (after puberty)
  • poor technique for landings
  • history of previous ACL injury
  • aggressive athlete with higher skill level
  • use of cleats or spikes
  • rough or uneven playing surface
  • ground condition/weather
  • fatigue
  • adolescent, young adults, and middle-aged athletes
More risk factors

Diagnostic investigations

1st investigations to order

  • x-rays
More 1st investigations to order

Investigations to consider

  • MRI
  • arthroscopy
More investigations to consider

Treatment algorithm


sedentary patients

moderate intensity demands

intense dynamic demands



Philip H. Cohen, MD
Philip H. Cohen

Clinical Assistant Professor of Medicine

Robert Wood Johnson Medical School

University of Medicine and Dentistry of New Jersey




PHC has been reimbursed by MCE Conferences for providing lectures and workshops in sports medicine.

Peer reviewers

James C. Puffer, MD


University of Kentucky School of Medicine

President and Chief Executive Officer

American Board of Family Medicine




JCP declares that he has no competing interests.

Jung-Ro Yoon, MD


Department of Orthopedic Surgery

Seoul Veterans Hospital


South Korea


JRY declares that she has no competing interests.

  • Anterior cruciate ligament injury images
  • Differentials

    • Medial collateral ligament (MCL) sprain
    • Posterior collateral ligament (PCL) sprain
    • Lateral collateral ligament (LCL) sprain
    More Differentials
  • Guidelines

    • AAOS management of anterior cruciate ligament injuries
    • ACR appropriateness criteria - acute trauma to the knee
    More Guidelines
  • Patient leaflets

    Anterior cruciate ligament injury

    More Patient leaflets
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