title: Structural Properties of the Meniscal Roots.
abstract: BACKGROUND
  Current surgical techniques for meniscal root repair reattach the most prominent, dense portion of the meniscal root and fail to incorporate recently identified peripheral, supplemental attachment fibers. The contribution of supplemental fibers to the biomechanical properties of native meniscal roots is unknown.
  
  
  OBJECTIVE
  The purpose was to quantify the ultimate failure strengths, stiffness, and attachment areas of the native posterior medial (PM), posterior lateral (PL), anterior medial (AM), and anterior lateral (AL) meniscal roots compared with the most prominent, dense meniscal root attachment after sectioning of supplemental fibers. It was hypothesized that the ultimate failure strength, stiffness, and attachment area of each native root would be significantly higher than those of the respective sectioned root.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Twelve matched pairs of male human cadaveric knees were used. The 4 native meniscal roots were left intact in the native group, whereas the roots in the contralateral knee (sectioned group) were dissected free of all supplemental fibers. A coordinate measuring device quantified the amount of tissue resected in the sectioned group compared with the native group. A dynamic tensile testing machine pulled each root in line with its circumferential fibers. All root attachments were preconditioned from 10 to 50 N at a rate of 0.1 Hz for 10 cycles and subsequently pulled to failure at a rate of 0.5 mm/s.
  
  
  RESULTS
  Supplemental fibers composed a significant percentage of the native PM, PL, and AM meniscal root attachment areas. Mean ultimate failure strengths (in newtons) of the native PM, PL, and AM roots were significantly higher than those of the sectioned state, while the ultimate failure strength of the native AL root was indistinguishable from that of the sectioned state.
  
  
  CONCLUSIONS
  Three of the 4 meniscal root attachments (PM, PL, AM) contained supplemental fibers that accounted for a significant percentage of the native root attachment areas, and these fibers significantly contributed to the failure strengths of the native roots.
  
  
  CONCLUSIONS
  These supplemental fibers are not routinely reattached during root repair surgery, suggesting that current techniques fail to reattach the biomechanically relevant attachments of native meniscal roots.
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA The Steadman Clinic, Vail, Colorado, USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Ellman
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: LaPrade
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors.forename: Sean D
authors.initials: SD
authors.lastname: Smith
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Rasmussen
authors.affiliation: Department of Orthopaedic Surgery, Oslo University Hospital and Faculty of Medicine, University of Oslo, Oslo, Norway Oslo Sports Trauma Research Center, Norwegian School of Sport Sciences, Oslo, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors.forename: Coen A
authors.initials: CA
authors.lastname: Wijdicks
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA The Steadman Clinic, Vail, Colorado, USA drlaprade@sprivail.org.
authors.forename: Robert F
authors.initials: RF
authors.lastname: LaPrade
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D008297:Male; D008592:Menisci, Tibial / Q000033:anatomy & histology* / Q000502:physiology* / Q000601:surgery; D008875:Middle Aged; D013718:Tensile Strength
keywords: lateral meniscus; meniscal repair; meniscus root; posterior meniscus root, medial meniscus; root repair