title: The equine forelimb suspensory ligament exhibits a heterogeneous strain pattern under tensile load.
abstract: OBJECTIVE
  To determine if regional variations in strain patterns occur within the suspensory ligament under tensile load. Local increases in strain may put certain regions of the suspensory ligament at risk and may explain the poor healing and high recurrence rates associated with suspensory branch injuries.
  
  
  METHODS
  The suspensory ligament and its bone attachments were isolated from each of 10 adult equine cadaveric forelimbs and radiodense reference beads were inserted throughout the length of the ligament. Specimens were attached to a custom fixture secured to a materials testing system. Radiographs were acquired at 50, 445, 1112, and 2224 N of applied tensile load. Changes in distances between the beads in each region of the suspensory ligament were measured and the regional strain was calculated. Significant differences were determined using a repeated-measures analysis of variance.
  
  
  RESULTS
  The suspensory ligament exhibited significant differences in regional strain (p <0.001). The distal branches of the suspensory ligament had significantly greater strains than the proximal (p = 0.025) and mid-body (p = 0.002) regions. The mid-body of the suspensory ligament also exhibited local strain variation, with the distal mid-body having significantly higher strains than the proximal mid-body (p = 0.038).
  
  
  CONCLUSIONS
  The equine suspensory ligament demonstrates a heterogeneous strain pattern during tensile loading, with the distal regions exhibiting significantly more strain than the proximal region. The non-homogenous strain pattern could explain the regional difference in injury and re-injury rates.
authors.forename: M
authors.initials: M
authors.lastname: Lavagnino
authors.forename: J
authors.initials: J
authors.lastname: Madison
authors.forename: M R
authors.initials: MR
authors.lastname: Williams
authors.affiliation: Steven Paul Arnoczky, DVM, College of Veterinary Medicine, 784 Wilson Road, G-387, Michigan State University, East Lansing, MI 48824, United States, Phone: +1 517 353 8964, Fax: +1 517 353 8980, E-mail: arnoczky@cvm.msu.edu.
authors.forename: S P
authors.initials: SP
authors.lastname: Arnoczky
mesh_terms: D000818:Animals; D005260:Female; D005552:Forelimb / Q000502:physiology; D006736:Horses / Q000033:anatomy & histology / Q000502:physiology*; D008023:Ligaments, Articular / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D011859:Radiography; D013718:Tensile Strength / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology
keywords: Equine; strain; suspensory ligament