title: Biomechanical behavior of bone scaffolds made of additive manufactured tricalciumphosphate and titanium alloy under different loading conditions.
abstract: OBJECTIVE
  The repair of large segmental bone defects caused by fracture, tumor or infection remains challenging in orthopedic surgery. The capability of two different bone scaffold materials, sintered tricalciumphosphate and a titanium alloy (Ti6Al4V), were determined by mechanical and biomechanical testing.
  
  
  METHODS
  All scaffolds were fabricated by means of additive manufacturing techniques with identical design and controlled pore geometry. Small-sized sintered TCP scaffolds (10 mm diameter, 21 mm length) were fabricated as dense and open-porous samples and tested in an axial loading procedure. Material properties for titanium alloy were determined by using both tensile (dense) and compressive test samples (open-porous). Furthermore, large-sized open-porous TCP and titanium alloy scaffolds (30 mm in height and diameter, 700 µm pore size) were tested in a biomechanical setup simulating a large segmental bone defect using a composite femur stabilized with an osteosynthesis plate. Static physiologic loads (1.9 kN) were applied within these tests.
  
  
  RESULTS
  Ultimate compressive strength of the TCP samples was 11.2 ± 0.7 MPa and 2.2 ± 0.3 MPa, respectively, for the dense and the open-porous samples. Tensile strength and ultimate compressive strength was 909.8 ± 4.9 MPa and 183.3 ± 3.7 MPa, respectively, for the dense and the open-porous titanium alloy samples. Furthermore, the biomechanical results showed good mechanical stability for the titanium alloy scaffolds. TCP scaffolds failed at 30% of the maximum load.
  
  
  CONCLUSIONS
  Based on recent data, the 3D printed TCP scaffolds tested cannot currently be recommended for high load-bearing situations. Scaffolds made of titanium could be optimized by adapting the biomechanical requirements.
authors.affiliation: Department of Orthopedics, Biomechanics and Implant Technology Research Laboratory, University Medicine Rostock, Rostock - Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Wieding
authors.forename: Andreas
authors.initials: A
authors.lastname: Fritsche
authors.forename: Peter
authors.initials: P
authors.lastname: Heinl
authors.forename: Carolin
authors.initials: C
authors.lastname: Körner
authors.forename: Matthias
authors.initials: M
authors.lastname: Cornelsen
authors.forename: Hermann
authors.initials: H
authors.lastname: Seitz
authors.forename: Wolfram
authors.initials: W
authors.lastname: Mittelmeier
authors.forename: Rainer
authors.initials: R
authors.lastname: Bader
mesh_terms: D000497:Alloys; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D019245:Compressive Strength; D017076:Computer-Aided Design; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D013718:Tensile Strength; D054457:Tissue Scaffolds; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D018786:Bone Substitutes; D002130:Calcium Phosphates; C031462:titanium alloy (TiAl6V4); D014025:Titanium; C018392:tricalcium phosphate