title: Dynamic contact mechanics of radial tears of the lateral meniscus: implications for treatment.
abstract: OBJECTIVE
  To characterize the effect of radial tears (RTs) of the lateral meniscus and their subsequent treatment (inside-out repair, partial meniscectomy) on joint contact mechanics during simulated gait.
  
  
  METHODS
  Six human cadaveric knees were mounted on a simulator programmed to mimic human gait. A sensor was inserted below the lateral meniscus to measure peak joint contact pressure location, magnitude, and contact area. The following conditions were compared: intact meniscus, 30% RT (at the popliteal hiatus), 60% RT, 90% RT, repair, and partial meniscectomy. Data were analyzed in the midstance phase of gait (14% and 45%) when axial force was at its highest (2,100 N).
  
  
  RESULTS
  Intact knees had peak contact pressures of 5.9 ± 0.9 MPa and 6.4 ± 1.1 MPa at 14% and 45% of gait, respectively. RTs of up to and including 60% had no effect on pressure magnitude or location. RTs of 90% resulted in significantly increased peak pressure (8.4 ± 1.1 MPa) in the postero-peripheral aspect of the tibial plateau and reduced contact area versus the intact knee, at 45% of gait. Repair resulted in a significant decrease in peak pressure (7.7 ± 1.0 MPa) relative to 90% RT but had no effect on contact area. Partial lateral meniscectomy resulted in areas and pressures that were not significantly different from 90% tears (8.7 ± 1.5 MPa).
  
  
  CONCLUSIONS
  Simulated large RTs of the lateral meniscus in the region of the popliteal hiatus show unfavorable dynamic contact mechanics that are not significantly different from those resulting from a partial lateral meniscectomy. Pressure was significantly reduced with inside-out repair but was not affected by partial meniscectomy; contact area was not restored to that of the intact condition for either procedure.
  
  
  CONCLUSIONS
  Large RTs in the region of the popliteal hiatus show unfavorable dynamic contact mechanics.
authors.affiliation: MedSport, University of Michigan, Ann Arbor, Michigan 48106, USA. abedi@umich.edu
authors.forename: Asheesh
authors.initials: A
authors.lastname: Bedi
authors.forename: Natalie
authors.initials: N
authors.lastname: Kelly
authors.forename: Michael
authors.initials: M
authors.lastname: Baad
authors.forename: Alice J S
authors.initials: AJ
authors.lastname: Fox
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Russell F
authors.initials: RF
authors.lastname: Warren
authors.forename: Suzanne A
authors.initials: SA
authors.lastname: Maher
mesh_terms: D001696:Biomechanical Phenomena; D005684:Gait; D006801:Humans; D008592:Menisci, Tibial / Q000503:physiopathology / Q000601:surgery; D019637:Orthopedic Procedures / Q000379:methods*; D011312:Pressure; D013314:Stress, Mechanical; D000070600:Tibial Meniscus Injuries; D016474:Weight-Bearing