title: The biomechanical performance of bone block and soft-tissue posterior cruciate ligament graft fixation with interference screw and cross-pin techniques.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the biomechanical properties of 4 different graft fixation constructs on the tibial side of the posterior cruciate ligament with reconstruction by use of an Achilles tendon graft.
  
  
  METHODS
  Biomechanical testing of 4 different fixation techniques was performed on 20 human cadaveric tibias and Achilles tendons. Cross-pin fixation with bone blocks (group A), interference screw fixation with bone blocks (group B), cross-pin fixation of soft tissue with backup fixation (group C), and interference screw fixation of soft tissue with backup fixation (group D) were tested. The tibia-graft fixation complex was cyclically loaded between 50 N and 250 N at 1 Hz for 1,000 cycles. After cycling, the amount of graft displacement was determined by measuring the change in grip-to-grip distance. The complex was then loaded to failure at 1 mm/s, and maximum failure load, stiffness, and mode of failure were determined.
  
  
  RESULTS
  Group C had a higher maximum failure load and stiffness than groups A and B (P < .05 and P < .001, respectively) but poor results for displacement (P < .05 and P < .05, respectively). The failure modes were bone block fracture, graft laceration, or cross-pin fracture in the cross-pin groups and graft pullout in the interference screw groups.
  
  
  CONCLUSIONS
  Our study suggests that maximum failure load and stiffness of hybrid fixation for Achilles tendon graft are comparable to those of both single calcaneal bone plug fixation methods that we studied. However, tendon graft displacement was significantly greater regardless of fixation method when compared with bone plug fixation.
  
  
  CONCLUSIONS
  Hybrid fixation for soft-tissue graft on the tibial fixation site provides comparable biomechanical properties of bone-to-bone fixation.
authors.affiliation: Department of Orthopaedic Surgery, Korea University College of Medicine, Guro Hospital, Seoul, South Korea.
authors.forename: Hong Chul
authors.initials: HC
authors.lastname: Lim
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Bae
authors.forename: Joon Ho
authors.initials: JH
authors.lastname: Wang
authors.forename: Tae Soo
authors.initials: TS
authors.lastname: Bae
authors.forename: Cheol Woong
authors.initials: CW
authors.lastname: Kim
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Hwang
authors.forename: Ji Yeol
authors.initials: JY
authors.lastname: Yoon
mesh_terms: D020341:Absorbable Implants; D000328:Adult; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001863:Bone Screws; D002102:Cadaver; D006801:Humans; D008875:Middle Aged; D009984:Orthopedic Fixation Devices; D016119:Posterior Cruciate Ligament / Q000637:transplantation*; D019651:Plastic Surgery Procedures / Q000379:methods*; D013718:Tensile Strength; D013977:Tibia / Q000601:surgery*; D014019:Tissue Donors; D017211:Treatment Failure; D016896:Treatment Outcome