title: Evaluation of meniscal extrusion with posterior root disruption and repair using ultrasound.
abstract: BACKGROUND
  Ultrasound techniques have been utilized for detection of discrete meniscus tears and extrusion. Meniscal extrusion is associated with increased contact pressure and decreased contact area contributing to the advancement of knee osteoarthritis. The purpose of this biomechanical study was to detect meniscal extrusion using a clinically available, portable ultrasound device. And further, to show that extent of injury and a weight-bearing state correlate with amount of extrusion.
  
  
  METHODS
  A portable, hand-held ultrasound was utilized to image the lateral meniscus in association with (1) an intact posterior root attachment, (2) a 50% cut, (3) a 100% cut, and (4) repaired posterior root attachment. Images were obtained in an unloaded condition, and again under a static, physiologic (70kg) axial load for above injury levels, and again following repair.
  
  
  RESULTS
  Significant differences in extrusion were noted between the intact and both the 50% cut (p=0.028) and 100% cut groups (p<0.001) all in the loaded position. No significant difference was found in extrusion between intact state and repaired posterior root in the axially loaded position (p=0.174). Both load (p=0.003) and injury level (p=0.005) had significant effects on the mean extrusion of the lateral meniscus.
  
  
  CONCLUSIONS
  Sectioning of the lateral meniscus posterior root will produce significantly increased lateral extrusion of the meniscus under physiologic loads. Unlike MRI evaluation, weight-bearing ultrasound images allow a functional assessment of meniscus extrusion. Trans-tibial posterior root repair can restore the lateral meniscus position and integrity.
  
  
  CONCLUSIONS
  This weight-bearing ultrasound technique can be an important assessment tool for complete evaluation of meniscus injuries.
authors.affiliation: University of Kansas Medical Center, Kansas City, KS, United States. Electronic address: growland@kumc.edu.
authors.forename: Grant
authors.initials: G
authors.lastname: Rowland
authors.affiliation: University of Kansas Medical Center, Kansas City, KS, United States. Electronic address: dmar@kumc.edu.
authors.forename: Damon
authors.initials: D
authors.lastname: Mar
authors.affiliation: University of Kansas Medical Center, Kansas City, KS, United States. Electronic address: tmciff@kumc.edu.
authors.forename: Terence
authors.initials: T
authors.lastname: McIff
authors.affiliation: University of Kansas Medical Center, Kansas City, KS, United States. Electronic address: jnelson3@kumc.edu.
authors.forename: Joshua
authors.initials: J
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging*; D007718:Knee Injuries / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008592:Menisci, Tibial / Q000000981:diagnostic imaging* / Q000601:surgery; D008875:Middle Aged; D000070600:Tibial Meniscus Injuries / Q000000981:diagnostic imaging* / Q000601:surgery; D014463:Ultrasonography; D016474:Weight-Bearing; D055815:Young Adult
keywords: Extrusion; Meniscus; Meniscus repair; Root tear; Ultrasound