Last reviewed: 28 Oct 2023
Last updated: 28 Feb 2023
Summary
Definition
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
ACUTE
sedentary patients
moderate intensity demands
intense dynamic demands
Contributors
Authors
Philip H. Cohen, MD

Clinical Assistant Professor of Medicine
Robert Wood Johnson Medical School
University of Medicine and Dentistry of New Jersey
Piscataway
NJ
Disclosures
PHC has been reimbursed by MCE Conferences for providing lectures and workshops in sports medicine.
Peer reviewers
James C. Puffer, MD
Professor
University of Kentucky School of Medicine
President and Chief Executive Officer
American Board of Family Medicine
Lexington
KY
Disclosures
JCP declares that he has no competing interests.
Jung-Ro Yoon, MD
Director
Department of Orthopedic Surgery
Seoul Veterans Hospital
Seoul
South Korea
Disclosures
JRY declares that she has no competing interests.
Differentials
- Medial collateral ligament (MCL) sprain
- Posterior collateral ligament (PCL) sprain
- Lateral collateral ligament (LCL) sprain
More DifferentialsGuidelines
- AAOS management of anterior cruciate ligament injuries
- ACR appropriateness criteria - acute trauma to the knee
More GuidelinesPatient leaflets
Anterior cruciate ligament injury
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