title: Biomechanical consequences of a posterior root tear of the lateral meniscus: stabilizing effect of the meniscofemoral ligament.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effects of different types of lateral meniscus root tears in terms of tibiofemoral contact stress.
  
  
  METHODS
  Ten porcine knees each underwent five different testing conditions with the menisci intact, a simulated lateral posterior root tear with and without cutting the meniscofemoral ligament and with an artificial tear of the posterior root of the medial meniscus. Biomechanical testing was performed at 30° of flexion with an axial load of 100 N. A pressure sensor (st Sensor Type S2042, Novel, Munich) was used to measure the tibiofemoral contact area and the tibiofemoral contact pressure. Data were analyzed to assess the differences in contact area and tibiofemoral peak contact pressure among the five meniscal conditions.
  
  
  RESULTS
  There was no significant difference in mean contact pressure between the state with the menisci intact and an isolated posterior root tear of the lateral meniscus. In case of a root tear and a tear of the meniscofemoral ligament, the contact area decreased in comparison with the intact state of the menisci. After additional cutting of the meniscofemoral ligament, the tibiofemoral contact pressure was significantly higher in comparison with the intact state and the avulsion injury. In the medial compartment, joint compression forces were significantly increased in comparison with the intact state after cutting the posterior root of the medial meniscus (P < 0.05).
  
  
  CONCLUSIONS
  The consequence of a medial meniscus root tear is well known and was verified by this analysis. The results of the present study show that the biomechanical consequences of a lateral meniscus root tear depend on the state of the meniscofemoral ligament. An increase in tibiofemoral contact pressure is only to be expected in combined injuries of the meniscus root and the meniscofemoral ligaments.
  
  
  CONCLUSIONS
  Posterior lateral meniscus root tear might have a better prognosis in terms of the development of osteoarthritis when the meniscofemoral ligament is intact.
authors.affiliation: Klinik für Orthopädie und Unfallchirurgie, Martin Luther Krankenhaus, Caspar Theyss Strasse 27-34, Grunewald, Berlin, Germany. ph.forkel@gmx.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Forkel
authors.forename: Mirco
authors.initials: M
authors.lastname: Herbort
authors.forename: Martin
authors.initials: M
authors.lastname: Schulze
authors.forename: Dieter
authors.initials: D
authors.lastname: Rosenbaum
authors.forename: Lars
authors.initials: L
authors.lastname: Kirstein
authors.forename: Michael
authors.initials: M
authors.lastname: Raschke
authors.forename: Wolf
authors.initials: W
authors.lastname: Petersen
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D007718:Knee Injuries / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology*; D008023:Ligaments, Articular / Q000503:physiopathology*; D008592:Menisci, Tibial / Q000503:physiopathology*; D013314:Stress, Mechanical; D013552:Swine; D000070600:Tibial Meniscus Injuries