title: Comparison of the split stacked versus the split achilles allograft for dual femoral tunnel posterior cruciate ligament reconstruction.
abstract: BACKGROUND
  Cadaveric testing has shown that double-bundle reconstruction better replicates the native anatomy of the posterior cruciate ligament. With the current trend toward allograft Achilles posterior cruciate ligament reconstructions, the need to determine a graft configuration with the highest tensile and pull-out strength has become paramount.
  
  
  OBJECTIVE
  The split stacked Achilles allograft construct provides greater graft material to traverse the notch and provides increased load to failure at the tibial point of fixation compared with a standard monoblock Achilles allograft construct.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Eight matched pairs of Achilles allograft tendons were secured to 8 matched pairs of fresh-frozen human cadaveric tibiae. Group 1 consisted of single-block grafts (n = 8), and group 2 included the split stacked grafts (n = 8). The cross-sectional area of each graft's 2 collagenous bundles was measured with a micrometer. The graft constructs were pulled to ultimate failure at a rate of 50 mm/min on a materials testing machine.
  
  
  RESULTS
  The mean cross-sectional area of the group 2 split stacked grafts (76.6 +/- 3.1 mm(2)) was significantly greater than that of the group 1 single-block grafts (48.2 +/- 3.0 mm(2); P =.00006). The maximum load to failure of the group 2 construct was significantly greater (1383 +/- 102 N) than that of the group 1 single-block configuration (1020 +/- 136 N; P =.01).
  
  
  CONCLUSIONS
  These results indicate that the novel split stacked configuration of an Achilles tendon allograft provides a greater cross-sectional area of graft material across the joint as well as a significant increase in the overall load to failure strength compared with a standard monoblock Achilles allograft construct.
  
  
  CONCLUSIONS
  The split stacked Achilles graft is an efficient method for using the entire allograft. With maintenance and use of all collagen fibers, the split stacked Achilles construct provides essentially 2 grafts in 1 while only using a single tibial tunnel.
authors.affiliation: Keller Army Community Hospital, West Point, NY 10996, USA. thomas.deberardino@na.amedd.army.mil
authors.forename: Thomas M
authors.initials: TM
authors.lastname: DeBerardino
authors.forename: Keith T
authors.initials: KT
authors.lastname: Lonergan
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Brooks
mesh_terms: D000125:Achilles Tendon / Q000033:anatomy & histology / Q000637:transplantation*; D000328:Adult; D000368:Aged; D001182:Arthroscopy / Q000379:methods*; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000601:surgery*; D013977:Tibia / Q000601:surgery*