title: Effect of varying the length of soft-tissue grafts in the tibial tunnel in a canine anterior cruciate ligament reconstruction model.
abstract: OBJECTIVE
  To investigate the effect of graft length within the bone tunnel on tendon-bone healing at an early stage after anterior cruciate ligament (ACL) reconstruction using Achilles tendon autograft in a canine model.
  
  
  METHODS
  We divided 40 adult dogs into 4 groups (n = 10 per group). Each dog underwent ACL reconstruction with Achilles tendon autograft in both knees. In groups I, II, III, and IV, the graft length within the tibia tunnel was 5 mm, 10 mm, 15 mm, and 20 mm, respectively. Five dogs in each group were killed 6 and 12 weeks postoperatively, with 3 knees used for histologic observation and 7 knees for mechanical testing.
  
  
  RESULTS
  Six weeks after surgery, the histologic scores in group I were lower than those in the other groups (P < .01) and those in group II were lower than those in group III and group IV (P < .01). However, there was no difference between group III and group IV (P > .05). At 12 weeks, there were no significant differences in histologic scores between groups (P > .05). The biomechanical test at 6 weeks showed that the mean graft pullout strength improved from group I to group IV. Except between groups III and IV (P = .142), there was a significant difference in the pullout strength among other groups. At week 12, the failure points were in the midsubstance of most specimens and more tibial-side graft pullout was found in group I than in the other groups (P < .001).
  
  
  CONCLUSIONS
  The histologic maturity and biomechanical strength of the tendon-bone junction after ACL reconstruction in dogs will be delayed at an early stage if the graft length in the bone tunnel is less than 15 mm.
  
  
  CONCLUSIONS
  There is a minimal acceptable amount of intratunnel tendon graft to allow satisfactory early tendon-bone healing, and attempts to save tendon graft length that lower the amount of intratunnel graft below a minimum of 15 mm should be avoided.
authors.affiliation: Department of Orthopaedic Surgery, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Li
authors.initials: L
authors.lastname: Qi
authors.forename: Cao
authors.initials: C
authors.lastname: Chang
authors.forename: Li
authors.initials: L
authors.lastname: Jian
authors.forename: Tang
authors.initials: T
authors.lastname: Xin
authors.forename: Zhong
authors.initials: Z
authors.lastname: Gang
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D004285:Dogs; D005500:Follow-Up Studies; D007718:Knee Injuries / Q000601:surgery; D013710:Tendons / Q000033:anatomy & histology / Q000637:transplantation*; D013977:Tibia / Q000601:surgery*; D014182:Transplantation, Autologous; D014945:Wound Healing