title: Meniscal translocation and deformation throughout the range of motion of the equine stifle joint: an in vitro cadaveric study.
abstract: BACKGROUND
  By study of the translocation and deformation of equine menisci throughout the range of motion, it may be possible to identify potential mechanical factors in the pathogenesis of injury to the cranial horn of the medial meniscus.
  
  
  OBJECTIVE
  To quantitatively document meniscal translocation and deformation using radiographic and MR imaging, and to evaluate for potential variation between the medial and lateral menisci.
  
  
  METHODS
  Radiographic markers were embedded in the periphery of the menisci in 6 cadaver stifles. Proximal-distal radiographs were taken at 15° intervals ranging from full flexion (30°) to full extension (160°). Magnetic resonance imaging sequences of 3 additional cadaver stifles were obtained in axial and sagittal planes at the predetermined stifle angles.
  
  
  RESULTS
  A significantly greater overall mean cranial-caudal translocation (1.6 times) of the lateral meniscus relative to the medial was seen from full extension to full flexion (P = 0.002). The cranial horn of the medial meniscus was the least mobile of the 4 horns, yet a significant cranial displacement relative to the cranial horn of the lateral meniscus was seen in the terminal 10° of extension. MRI images revealed a significantly greater axial compressive strain in the cranial horn of the medial meniscus relative to the cranial horn of the lateral meniscus in the terminal 10° of extension (P = 0.017).
  
  
  CONCLUSIONS
  The equine menisci exhibit a cranial-caudal translocation over the tibia throughout the range of motion. While the cranial horn of the medial meniscus is the least mobile of the 4 horns, it undergoes significant cranial translocation and axial compression in the terminal 10° of extension.
  
  
  CONCLUSIONS
  Hyperextension of the stifle may place the cranial horn of the medial meniscus at risk of injury and thus explain the higher prevalence of meniscal tears at this location.
authors.affiliation: Department of Large Animal Clinical Studies, College of Veterinary Medicine, Michigan State University, USA. fowlie@cvm.msu.edu
authors.forename: J G
authors.initials: JG
authors.lastname: Fowlie
authors.forename: S P
authors.initials: SP
authors.lastname: Arnoczky
authors.forename: J A
authors.initials: JA
authors.lastname: Stick
authors.forename: A P
authors.initials: AP
authors.lastname: Pease
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002102:Cadaver; D006736:Horses / Q000033:anatomy & histology* / Q000502:physiology*; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D013264:Stifle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*