title: Subluxation of the peroneus long tendon in the cuboid tunnel: is it normal or pathologic? An ultrasound and magnetic resonance imaging study.
abstract: OBJECTIVE
  To evaluate the position of the peroneus longus (PL) tendon relative to the cuboid tuberosity and cuboid tunnel during ankle dorsiflexion and plantarflexion using ultrasound and MRI.
  
  
  METHODS
  The study population included two groups: 20 feet of 10 asymptomatic volunteers who underwent prospective dynamic ultrasound and 55 ankles found through retrospective review of routine ankle MRI examinations. The location of the PL tendon at the cuboid tuberosity and cuboid tunnel was designated as completely within the tunnel, indeterminate, or subluxed with respect to ankle dorsiflexion and plantarflexion.
  
  
  RESULTS
  On dynamic ultrasound, the PL tendon was perched plantar to the cuboid tuberosity in dorsiflexion, and glided to enter the cuboid tunnel distal to the tuberosity in plantarflexion in all 20 feet. On the MRI evaluation, there was a statistically significant difference (p = 0.0006) in the location of the PL tendon between the ankles scanned in dorsiflexion and plantarflexion.
  
  
  CONCLUSIONS
  Based on our findings on ultrasound and MRI, the PL tendon can glide in and out of the cuboid tunnel along the cuboid tuberosity depending on ankle position. Thus, "subluxation" of the tendon as it curves to enter the cuboid tunnel, which to the best of our knowledge has not yet been described, should be recognized as a normal, position-dependent phenomenon and not be reported as pathology.
authors.affiliation: Charlotte Radiology, Charlotte, NC, USA. taylor.stone@charlotteradiology.com.
authors.forename: Taylor J
authors.identifier: http://orcid.org/0000-0002-9615-0876
authors.initials: TJ
authors.lastname: Stone
authors.affiliation: New York Langone Medical Center / Hospital for Joint Diseases, New York, NY, USA.
authors.forename: Zehava S
authors.initials: ZS
authors.lastname: Rosenberg
authors.affiliation: Cedimed-Dinamica, Medellin, Colombia.
authors.forename: Zoraida Restrepo
authors.initials: ZR
authors.lastname: Velez
authors.affiliation: New York Langone Medical Center / Hospital for Joint Diseases, New York, NY, USA.
authors.forename: Gina
authors.initials: G
authors.lastname: Ciavarra
authors.affiliation: Marino Hospital ASL Cagliari, Cagliari, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Prost
authors.affiliation: New York Langone Medical Center / Hospital for Joint Diseases, New York, NY, USA.
authors.forename: Jenny T
authors.initials: JT
authors.lastname: Bencardino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013639:Tarsal Bones / Q000000981:diagnostic imaging*; D052256:Tendinopathy / Q000000981:diagnostic imaging*; D013708:Tendon Injuries / Q000000981:diagnostic imaging*; D013710:Tendons / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult
keywords: MRI; Peroneus longus; Plantar foot; Subluxation; Tendon subluxation; Ultrasound