title: Effects of stress deprivation on mechanical properties of the in situ frozen-thawed semitendinosus tendon in rabbits.
abstract: OBJECTIVE
  To clarify the effect of complete stress deprivation on the mechanical properties of the in situ frozen-thawed semitendinosus tendon, an idealized autograft model.
  
  
  METHODS
  Ninety-six rabbits were divided into three groups. In the frozen group (n=36), we applied the freeze-thaw treatment to the semitendinosus tendon to necrotize fibroblasts in the tendon. In the frozen and stress-shielded group (n=30), after we applied the same freeze-thaw treatment to the tendon, we completely released the tendon from stress. In the sham group (n=30), a sham operation was applied. In each group, 6 rabbits were sacrificed at 0 (only in the frozen group), 1, 2, 3, 6 and 12 weeks after surgery.
  
  
  BACKGROUND
  Previous studies have not clarified remodeling of the semitendinosus autograft in ligament reconstruction or its idealized model.
  
  
  METHODS
  The tendon was frozen with liquid nitrogen. The tendon was released from stress with the originally developed technique using a polyester tape. In each period, 5 out of the 6 rabbits were evaluated with tensile testing, and the remaining rabbit was histologically observed.
  
  
  RESULTS
  Complete stress shielding significantly increased the cross-sectional area of the frozen-thawed tendon at 1 and 2 weeks, while it significantly inhibited the increase of the area due to the freeze-thaw treatment at 3 and 6 weeks. Complete stress shielding significantly reduced material properties of the frozen-thawed tendon after 2 weeks.
  
  
  CONCLUSIONS
  The frozen-thawed semitendinosus tendon has unique remodeling characteristics under a stress-shielded condition, which were not the same as those of the frozen-thawed patellar tendon.
  
  
  CONCLUSIONS
  Remodeling of the semitendinosus tendon autograft under stress-shielded conditions may be different from that of the patellar tendon autograft.
authors.affiliation: Department of Medical Bioengineering and Sports Medicine, Hokkaido University School of Medicine, Kita-15 Nishi 7, Kita-ku, 060 8638, Sapporo, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Hara
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yasuda
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kimura
authors.forename: Tokifumi
authors.initials: T
authors.lastname: Majima
authors.forename: Akio
authors.initials: A
authors.lastname: Minami
authors.forename: Harukazu
authors.initials: H
authors.lastname: Tohyama
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004548:Elasticity; D005615:Freezing; D007717:Knee / Q000502:physiology; D011817:Rabbits; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013710:Tendons / Q000166:cytology* / Q000502:physiology* / Q000637:transplantation; D013718:Tensile Strength