title: Biomechanical stability of novel mechanically adapted open-porous titanium scaffolds in metatarsal bone defects of sheep.
abstract: Open-porous titanium scaffolds for large segmental bone defects offer advantages like early weight-bearing and limited risk of implant failure. The objective of this experimental study was to determine the biomechanical behavior of novel open-porous titanium scaffolds with mechanical-adapted properties in vivo. Two types of the custom-made, open-porous scaffolds made of Ti6Al4V (Young's modulus: 6-8 GPa and different pore sizes) were implanted into a 20 mm segmental defect in the mid-diaphysis of the metatarsus of sheep, and were stabilized with an osteosynthesis plate. After 12 and 24 weeks postoperatively, torsional testing was performed on the implanted bone and compared to the contralateral non-treated side. Maximum torque, maximum angle, torsional stiffness, fracture energy, shear modulus and shear stress were investigated. Furthermore, bone mineral density (BMD) of the newly formed bone was determined. Mechanical loading capabilities for both scaffolds were similar and about 50% after 12 weeks (e.g., max. torque of approximately 20 Nm). A further increase after 24 weeks was found for most of the investigated parameters. Results for torsional stiffness and shear modulus as well as bone formation depended on the type of scaffold. Increased BMD after 24 weeks was found for one scaffold type but remained constant for the other one. The present data showed the capability of mechanically adapted open-porous titanium scaffolds to function as bone scaffolds for large segmental defects and the influence of the scaffold's stiffness. A further increase in the biomechanical stability can be assumed for longer observation periods of greater than six months.
authors: Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, 18057 Rostock, Germany. Electronic address: jan.wieding@med.uni-rostock.de.
authors: Jan
authors: J
authors: Wieding
authors: Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, 18057 Rostock, Germany; Pre-clinical Imaging Research Group, University Medicine Rostock, Doberaner Straße 140, 18057 Rostock, Germany.
authors: Tobias
authors: T
authors: Lindner
authors: Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, 18057 Rostock, Germany.
authors: Philipp
authors: P
authors: Bergschmidt
authors: Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, 18057 Rostock, Germany.
authors: Rainer
authors: R
authors: Bader
mesh_terms: D000497:Alloys; D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D002113:Calcification, Physiologic / Q000187:drug effects; D005260:Female; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D020007:Implants, Experimental; D007834:Lasers; D008422:Materials Testing; D008682:Metatarsal Bones / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D010012:Osteogenesis / Q000187:drug effects; D016062:Porosity; D011859:Radiography; D012756:Sheep; D054457:Tissue Scaffolds / Q000737:chemistry*; D014025:Titanium / Q000494:pharmacology*
chemical_list: D000497:Alloys; C031462:titanium alloy (TiAl6V4); D014025:Titanium
keywords: In vivo; Metatarsus; Open-porous titanium scaffolds; Segmental defects; Sheep; Torsional testing