ContentsSynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyReferencesView all Images (8)
Anterior cruciate ligament injury
Other Resources UpToDate PubMed

Anterior cruciate ligament injury

Contributors: Colin M. Robbins, Sandeep Mannava MD, PhD
Other Resources UpToDate PubMed

Synopsis

Causes / typical injury mechanism / pathophysiology: Anterior cruciate ligament (ACL) injuries typically occur during athletic activities. The mechanism of injury often involves a deceleration or acceleration force in combination with increased valgus load on the knee. The most common mechanism is a noncontact cutting injury.

Another cause of ACL injuries are knee dislocations in the setting of high-energy traumatic injuries. In these cases, careful attention should be taken to assess other ligamentous and possible neurovascular injuries to the knee joint.

Classic history and presentation: Active, younger patients will more commonly rupture their ACL. A common presentation includes a patient who reports hearing / feeling a "pop" at the time of injury during an athletic activity. Additionally, hemarthrosis will commonly be seen within 2 hours of the suspected injury.

Prevalence:
  • Age – Mean age of incidence is 29 years (+/- 11 years), but this injury can occur across all ages. Peak incidence varies based on sex:
    • Male peak incidence – 19-25 years old
    • Female peak incidence – 14-18 years old
  • Sex / gender – Both sexes can be affected, with a higher rate seen in the female population.
Risk factors:
  • Noncontact and contact sports activities (eg, football, lacrosse, soccer, basketball).
  • Anatomical risk factors for youth include increased anterior pelvic tilt, increased femoral anteversion, narrow intercondylar notch, increased posterior tibial slope, and a small ACL.
  • Female sex hormones (estradiol).
  • A valgus knee (anatomic versus dynamic). In dynamic valgus, the combination of adduction of the hip and valgus moment on the knee upon landing results in increased strain on the ACL.
  • Neuromuscular activation patterns (quad dominant).
Grade / classification system:
  • Lachman grade 1 – 3-5 mm anterior translation of the tibia in relation to the femur
  • Lachman grade 2 – 5-10 mm anterior translation of the tibia in relation to the femur
  • Lachman grade 3 – greater than 10 mm anterior translation of the tibia in relation to the femur
  • Modifiers –
    • A: firm endpoint
    • B: no endpoint

Codes

ICD10CM:
S83.519A – Sprain of anterior cruciate ligament of unspecified knee, initial encounter

SNOMEDCT:
444470001 – Injury of anterior cruciate ligament

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

Pitfalls:
  • If the mechanism of injury is high energy with a knee dislocation, be very diligent in assessing multiligamentous knee injury and neurovascular compromise, as the popliteal neurovascular bundle lies directly posterior to the knee joint.
  • Delay in diagnosis with the patient continuing to participate in higher risk activities (eg, soccer, basketball) can result in irreparable damage to the meniscus and cartilage.

Best Tests

Subscription Required

Management Pearls

Subscription Required

Therapy

Subscription Required

References

Subscription Required

Last Reviewed:03/25/2021
Last Updated:03/25/2021
Copyright © 2021 VisualDx®. All rights reserved.
Anterior cruciate ligament injury
Anterior cruciate ligament injury : Hemarthrosis, Inability to bear weight, Knee pain, Lachman test positive, Knee instability
Copyright © 2021 VisualDx®. All rights reserved.