title: Medial knee injury: Part 2, load sharing between the posterior oblique ligament and superficial medial collateral ligament.
abstract: BACKGROUND
  There is limited information regarding directly measured load responses of the posterior oblique and superficial medial collateral ligaments in isolated and multiple medial knee ligament injury states.
  
  
  OBJECTIVE
  Tensile load responses from both the superficial medial collateral ligament and the posterior oblique ligament would be measurable and reproducible, and the native load-sharing relationships between these ligaments would be altered after sectioning of medial knee structures.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Twenty-four nonpaired, fresh-frozen adult cadaveric knees were distributed into 3 sequential sectioning sequences. Buckle transducers were applied to the posterior oblique ligament and the proximal and distal divisions of the superficial medial collateral ligament; 10 N.m valgus moments and 5 N.m internal and external rotation torques were applied at 0 degrees , 20 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion.
  
  
  RESULTS
  With an applied valgus and external rotation moment, there was a significant load increase on the posterior oblique ligament compared with the intact state after sectioning all other medial knee structures. With an applied external rotation torque, there was a significant load decrease on the proximal division of the superficial medial collateral ligament from the intact state after sectioning all other medial knee structures. With an applied external rotation torque, the distal division of the superficial medial collateral ligament experienced a significant load increase from the intact state after sectioning the posterior oblique ligament and the meniscofemoral division of the deep medial collateral ligament.
  
  
  CONCLUSIONS
  This study found alterations in the native load-sharing relationships of the medial knee structures after injury. Sectioning both the primary and secondary restraints to valgus and internal/external rotation of the knee alters the intricate load-sharing relationships that exist between the medial knee structures.
  
  
  CONCLUSIONS
  In cases in which surgical repair or reconstruction is indicated, consideration should be placed on repairing or reconstructing all injured medial knee structures to restore the native load-sharing relationships among these medial knee structures.
authors.affiliation: Orthopaedic Biomechanics Laboratory, Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, Minnesota 55454, USA.
authors.forename: Coen A
authors.initials: CA
authors.lastname: Wijdicks
authors.forename: Chad J
authors.initials: CJ
authors.lastname: Griffith
authors.forename: Robert F
authors.initials: RF
authors.lastname: LaPrade
authors.forename: Stanislav I
authors.initials: SI
authors.lastname: Spiridonov
authors.forename: Steinar
authors.initials: S
authors.lastname: Johansen
authors.forename: Bryan M
authors.initials: BM
authors.lastname: Armitage
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology*; D017888:Medial Collateral Ligament, Knee / Q000502:physiology*; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000502:physiology*; D016059:Range of Motion, Articular; D016474:Weight-Bearing / Q000502:physiology*