title: Embalmed and fresh frozen human bones in orthopedic cadaveric studies: which bone is authentic and feasible?
abstract: OBJECTIVE
  The most frequently used bones for mechanical testing of orthopedic and trauma devices are fresh frozen cadaveric bones, embalmed cadaveric bones, and artificial composite bones. Even today, the comparability of these different bone types has not been established.
  
  
  METHODS
  We tested fresh frozen and embalmed cadaveric femora that were similar concerning age, sex, bone mineral density, and stiffness. Artificial composite femora were used as a reference group. Testing parameters were pullout forces of cortex and cancellous screws, maximum load until failure, and type of fracture generated.
  
  
  RESULTS
  Stiffness and type of fracture generated (Pauwels III) were similar for all 3 bone types (fresh frozen: 969 N/mm, 95% confidence interval (CI): 897-1,039; embalmed: 999 N/mm, CI: 875-1,121; composite: 946 N/mm, CI: 852-1,040). Furthermore, no significant differences were found between fresh frozen and embalmed femora concerning pullout forces of cancellous screws (fresh frozen: 654 N, CI: 471-836; embalmed: 595 N, CI: 365-823) and cortex screws (fresh frozen: 1,152 N, CI: 894-1,408; embalmed: 1,461 N, CI: 880-2,042), and axial load until failure (fresh frozen: 3,427 N, CI: 2,564-4290; embalmed: 3,603 N, CI: 2,898-4,306). The reference group showed statistically significantly different results for pullout forces of cancellous screws (2,344 N, CI: 2,068-2,620) and cortex screws (5,536 N, CI: 5,203-5,867) and for the axial load until failure (> 7,952 N).
  
  
  CONCLUSIONS
  Embalmed femur bones and fresh frozen bones had similar characteristics by mechanical testing. Thus, we suggest that embalmed human cadaveric bone is a good and safe option for mechanical testing of orthopedic and trauma devices.
authors.affiliation: Departments of Trauma, Hand and Reconstructive Surgery, University Hospital Giessen and Marburg, Marburg, Germany. tobiastopp@gmail.com
authors.forename: Tobias
authors.initials: T
authors.lastname: Topp
authors.forename: Thorben
authors.initials: T
authors.lastname: Müller
authors.forename: Sebastian
authors.initials: S
authors.lastname: Huss
authors.forename: Peter Herbert
authors.initials: PH
authors.lastname: Kann
authors.forename: Eberhard
authors.initials: E
authors.lastname: Weihe
authors.forename: Steffen
authors.initials: S
authors.lastname: Ruchholtz
authors.forename: Ralph Peter
authors.initials: RP
authors.lastname: Zettl
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D005264:Femoral Fractures / Q000503:physiopathology / Q000601:surgery*; D005269:Femur / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D013314:Stress, Mechanical