title: Pullout strength of bone-patellar tendon-bone allograft bone plugs: a comparison of cadaver tibia and rigid polyurethane foam.
abstract: OBJECTIVE
  To compare the load-to-failure pullout strength of bone-patellar tendon-bone (BPTB) allografts in human cadaver tibias and rigid polyurethane foam blocks.
  
  
  METHODS
  Twenty BPTB allografts were trimmed creating 25 mm × 10 mm × 10 mm tibial plugs. Ten-millimeter tunnels were drilled in 10 human cadaver tibias and 10 rigid polyurethane foam blocks. The BPTB anterior cruciate ligament allografts were inserted into these tunnels and secured with metal interference screws, with placement of 10 of each type in each material. After preloading (10 N), cyclic loading (500 cycles, 10 to 150 N at 200 mm/min) and load-to-failure testing (200 mm/min) were performed. The endpoints were ultimate failure load, cyclic loading elongation, and failure mode.
  
  
  RESULTS
  No difference in ultimate failure load existed between grafts inserted into rigid polyurethane foam blocks (705 N) and those in cadaver tibias (669 N) (P = .69). The mean rigid polyurethane foam block elongation (0.211 mm) was less than that in tibial bone (0.470 mm) (P = .038), with a smaller standard deviation (0.07 mm for foam) than tibial bone (0.34 mm).
  
  
  CONCLUSIONS
  All BPTB grafts successfully completed 500 cycles. The rigid polyurethane foam block showed less variation in test results than human cadaver tibias.
  
  
  CONCLUSIONS
  Rigid polyurethane foam blocks provide an acceptable substitute for human cadaver bone tibia for biomechanical testing of BPTB allografts and offer near-equivalent results.
authors.affiliation: Plano Orthopedic Sports Medicine and Spine Center, Plano, Texas 75093, USA.
authors.forename: F Alan
authors.initials: FA
authors.lastname: Barber
mesh_terms: D000328:Adult; D064591:Allografts; D016118:Anterior Cruciate Ligament / Q000637:transplantation*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D018786:Bone Substitutes; D002102:Cadaver; D019544:Equipment Failure Analysis; D006801:Humans; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods; D010329:Patella / Q000601:surgery*; D011140:Polyurethanes; D013718:Tensile Strength / Q000502:physiology*; D013977:Tibia / Q000601:surgery*; D014184:Transplantation, Homologous
chemical_list: D018786:Bone Substitutes; D011140:Polyurethanes; C028279:polyurethane foam