title: Altered tibiofemoral contact mechanics due to lateral meniscus posterior horn root avulsions and radial tears can be restored with in situ pull-out suture repairs.
abstract: BACKGROUND
  An avulsion of the posterior root attachment of the lateral meniscus or a radial tear close to the root attachment can lead to degenerative knee arthritis. Although the biomechanical effects of comparable injuries involving the medial meniscus have been studied, we are aware of no such study involving the lateral meniscus. We hypothesized that in situ pull-out suture repair of lateral meniscus root avulsions and of complete radial tears 3 and 6 mm from the root attachment would increase the contact area and decrease mean and peak tibiofemoral contact pressures, at all knee flexion angles, relative to the corresponding avulsion or tear condition.
  
  
  METHODS
  Eight human cadaveric knees underwent biomechanical testing. Eight lateral meniscus conditions (intact, footprint tear, root avulsion, root avulsion repair, radial tears at 3 and 6 mm from the posterior root, and repairs of the 3 and 6-mm tears) were tested at five different flexion angles (0°, 30°, 45°, 60°, and 90°) under a compressive 1000-N load.
  
  
  RESULTS
  Avulsion of the posterior root of the lateral meniscus or an adjacent radial tear resulted in significantly decreased contact area and increased mean and peak contact pressures in the lateral compartment, relative to the intact condition, in all cases except the root avulsion condition at 0° of flexion. In situ pull-out suture repair of the root avulsion or radial tear significantly reduced mean contact pressures, relative to the corresponding avulsion or tear condition, when the results for each condition were pooled across all flexion angles.
  
  
  CONCLUSIONS
  Posterior horn root avulsions and radial tears adjacent to the root attachment of the lateral meniscus significantly increased contact pressures in the lateral compartment. In situ pull-out suture repairs of these tears significantly improved lateral compartment joint contact pressures.
  
  
  CONCLUSIONS
  In situ repair may be an effective treatment to improve tibiofemoral contact profiles after an avulsion of the posterior root of the lateral meniscus or a complete radial tear adjacent to the root. In situ repairs should be further investigated clinically as an alternative to partial lateral meniscectomy.
authors.affiliation: The Center for Outcome-Based Orthopedic Research (G.D.) and Department of Biomedical Engineering (C.M.L., K.S.J, S.D.S., C.A.W., and R.F.L.), Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657. E-mail address for R.F.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: LaPrade
authors.affiliation: The Center for Outcome-Based Orthopedic Research (G.D.) and Department of Biomedical Engineering (C.M.L., K.S.J, S.D.S., C.A.W., and R.F.L.), Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657. E-mail address for R.F.
authors.forename: Kyle S
authors.initials: KS
authors.lastname: Jansson
authors.affiliation: The Center for Outcome-Based Orthopedic Research (G.D.) and Department of Biomedical Engineering (C.M.L., K.S.J, S.D.S., C.A.W., and R.F.L.), Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657. E-mail address for R.F.
authors.forename: Grant
authors.initials: G
authors.lastname: Dornan
authors.affiliation: The Center for Outcome-Based Orthopedic Research (G.D.) and Department of Biomedical Engineering (C.M.L., K.S.J, S.D.S., C.A.W., and R.F.L.), Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657. E-mail address for R.F.
authors.forename: Sean D
authors.initials: SD
authors.lastname: Smith
authors.affiliation: The Center for Outcome-Based Orthopedic Research (G.D.) and Department of Biomedical Engineering (C.M.L., K.S.J, S.D.S., C.A.W., and R.F.L.), Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657. E-mail address for R.F.
authors.forename: Coen A
authors.initials: CA
authors.lastname: Wijdicks
authors.affiliation: The Center for Outcome-Based Orthopedic Research (G.D.) and Department of Biomedical Engineering (C.M.L., K.S.J, S.D.S., C.A.W., and R.F.L.), Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657. E-mail address for R.F.
authors.forename: Robert F
authors.initials: RF
authors.lastname: LaPrade
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008592:Menisci, Tibial / Q000503:physiopathology / Q000601:surgery*; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology; D013537:Sutures; D000070600:Tibial Meniscus Injuries; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology