title: Ultrasound assessment of dorsal lisfranc ligament strain under clinically relevant loads.
abstract: BACKGROUND
  Pure Lisfranc ligament injuries have a varied clinical presentation, making them difficult to diagnose. This study seeks to understand in vivo strain characteristics of the dorsal Lisfranc ligament under clinically relevant stress loads and foot orientations measured by ultrasound.
  
  
  METHODS
  Randomized ultrasound imaging trials were performed on 50 asymptomatic feet of 20-to-32-year-old individuals who were free of lower-extremity abnormalities. The dorsal Lisfranc ligament was ultrasound imaged under low, medium, and high stress while at 0° and 15° abducted foot orientations. Load was applied using a seated calf-raise apparatus, and a single examiner performed all of the tests. Two-way repeated-measures analysis of variance was used to determine any significant load or position main effects or load × position interaction.
  
  
  RESULTS
  Position main effect for dorsal Lisfranc ligament length demonstrated a significant overall increase in ligament length of 0.21 mm (P < .001), which reflects a 4.03% change in ligament length between the rectus and 15° abducted orientations. Furthermore, low and medium loads demonstrated significant length increase with position effect (P = .03 and P < .001, respectively). No significant load main effect or interaction was determined.
  
  
  CONCLUSIONS
  Dorsal Lisfranc ligament length undergoes more strain in an abducted foot position at the same load compared with in a rectus foot. We advocate measuring under a medium load if possible and comparing foot positions for the maximum length changes. The participant stress loads and foot positions used are clinically feasible, which makes it possible to perform this ultrasound procedure in the clinical setting.
authors: College of Podiatric Medicine and Surgery, Des Moines University, Des Moines, IA. Dr. Graves is now with the Department of Orthopedic Surgery and Rehabilitation, Division of Foot and Ankle, University of Florida at Jacksonville, Jacksonville, FL.
authors: Nathan C
authors: NC
authors: Graves
authors: David D
authors: DD
authors: Rettedal
authors: Joshua J
authors: JJ
authors: Marshall
authors: Katherine
authors: K
authors: Frush
authors: Vassilios
authors: V
authors: Vardaxis
mesh_terms: D000328:Adult; D001837:Body Weights and Measures; D005260:Female; D006801:Humans; D008023:Ligaments, Articular / Q000000981:diagnostic imaging* / Q000502:physiology*; D008297:Male; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging* / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results; D013484:Supination / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult