A threshold value of 3.5 mm of passive anterior tibial subluxation on MRI is highly specific for complete ACL tears

  • Alexandre Hardy
  • Shahnaz KloucheEmail author
  • Pierre Szarzynski
  • Etienne Charpentier
  • Jean Sebastien Beranger
  • Thomas Bauer
  • Benoit Rousselin
  • Olivia Judet
  • Philippe Hardy



To identify and quantify passive anterior tibial subluxation on MRI using a standardized measurement protocol and determine the diagnostic threshold of subluxation for complete anterior cruciate ligament tears.


A retrospective case–control study was performed. Patients who underwent surgery for a complete isolated ACL tear between 2009 and 2015 were matched for age and gender to controls with an intact ligament on knee MRI. All subjects underwent 1.5 T closed field MR imaging with the same protocol. Measurements were performed on axial sequences to evaluate translation of the medial and lateral condyles compared to the tibial plateau. Each compartment was measured between the vertical tangent to the posterior femoral condyles and the most posterior part of the tibial plateau. The main criterion was global passive subluxation measurements on MRI, corresponding to mean medial and lateral compartment subluxation. The reproducibility and diagnostic value of passive subluxation were calculated.


Sixty (30/30) subjects were included, mean age 27.1 ± 1.7 years, 20 women and 40 men. Patients had a significantly higher global passive subluxation than controls (3.3 ± 0.6 mm vs 0.6 ± 0.2 mm, respectively p < 0.00001). Reproducibility was excellent and the diagnostic value of passive subluxation for a complete ACL tear was fair. A passive subluxation threshold of 3.5 mm had a sensitivity of 55.2%, a specificity of 100% and 77.6% of well-classified subjects.


The calculated cutoff value for global passive subluxation to identify patients with a complete ACL tear was 3.5 mm, with excellent specificity and a high positive likelihood ratio. Suboptimal clinical results following ACL reconstruction could be partially due to failure to restore an anatomical femorotibial relationship.

Level of evidence



Anterior cruciate ligament (ACL) tear Passive anterior tibial subluxation (PATS) MRI 



There was no external funding source for the current study.

Compliance with ethical standards

Conflict of interest

The author(s) declare that they have no competing interests.

Ethical approval

Ethical approval was obtained for this study from the Comité de Protection des Personnes Ile-de-France IV (CPP IDF IV), Hôpital Saint-Louis. The database was declared at the National Commission for Data Protection (Commission Nationale de l’Informatique et des Libertés, CNIL, no. 470235).


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Copyright information

© European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2018

Authors and Affiliations

  • Alexandre Hardy
    • 1
  • Shahnaz Klouche
    • 1
    Email author
  • Pierre Szarzynski
    • 1
  • Etienne Charpentier
    • 1
  • Jean Sebastien Beranger
    • 1
  • Thomas Bauer
    • 1
    • 2
  • Benoit Rousselin
    • 1
  • Olivia Judet
    • 1
  • Philippe Hardy
    • 1
    • 2
  1. 1.Hôpital Ambroise Paré, Service de Chirurgie Orthopédique et TraumatologieHôpitaux Universitaires Paris Ile de France Ouest, Assistance Publique-Hôpitaux de ParisBoulogne-BillancourtFrance
  2. 2.Université de Versailles Saint-Quentin-en-Yvelines, UFR des Sciences de la SantéMontigny-le-BretonneuxFrance

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