title: Does the source of hemarthrosis influence posttraumatic joint contracture and biomechanical properties of the joint?
abstract: BACKGROUND
  Posttraumatic joint contracture is a common complication of intraarticular injuries and an associated traumatic hemarthrosis could be of importance for its development. The purpose of this investigation was to determine whether the source of the hemarthrosis (peripheral blood vs. bleeding from the bone marrow) affects the amount of contracture and its reversibility and biomechanical properties.
  
  
  METHODS
  46 New Zealand White rabbits were divided in 6 groups and 33 underwent 8 weeks immobilization with either hemarthrosis from bone marrow or peripheral blood. 16 rabbits underwent remobilization for another 8 weeks. 7 animals had only hemarthrosis (bone marrow) for 8 weeks, while 6 were used as controls. Analysis included mean contracture angle and biomechanical variables.
  
  
  RESULTS
  The immobilized animals had an increased contracture angle, the knee angle vs. force curve had a greater hysteresis and showed higher initial stiffness. There was no difference in biomechanical properties of the knee between the different types of hemarthroses. After 8 weeks remobilization most biomechanical properties were not different from control.
  
  
  CONCLUSIONS
  The origin of hemarthrosis, and therewith the presence of marrow-derived factors and pluripotential cells from bone marrow, does not seem to affect the severity of joint contractures nor their reversibility.
authors.affiliation: Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Monika
authors.initials: M
authors.lastname: Horisberger
authors.forename: Shermin
authors.initials: S
authors.lastname: Kazemkhani
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Monument
authors.forename: Daniela
authors.initials: D
authors.lastname: Emmenegger
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Hildebrand
authors.forename: Walter
authors.initials: W
authors.lastname: Herzog
mesh_terms: D000818:Animals; D003286:Contracture / Q000209:etiology* / Q000503:physiopathology*; D055119:Elastic Modulus; D006395:Hemarthrosis / Q000150:complications* / Q000503:physiopathology*; D007596:Joints / Q000293:injuries* / Q000503:physiopathology*; D011817:Rabbits; D016059:Range of Motion, Articular