title: A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model.
abstract: Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME).
  
  
  OBJECTIVE
  a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation, µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery.
authors.affiliation: Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany.
authors.forename: Christian W
authors.initials: CW
authors.lastname: Müller
authors.affiliation: Laser Zentrum Hannover e.V. (LZH), Hollerithallee 8, 30419 Hannover, Germany.
authors.forename: Ronny
authors.initials: R
authors.lastname: Pfeifer
authors.affiliation: Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany ; Small Animals Clinic, University of Veterinary Medicine, Bischofsholer Damm 15, 30173 Hannover, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Meier
authors.affiliation: Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Decker
authors.affiliation: Small Animals Clinic, University of Veterinary Medicine, Bischofsholer Damm 15, 30173 Hannover, Germany.
authors.forename: Janin
authors.initials: J
authors.lastname: Reifenrath
authors.affiliation: Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gösling
authors.affiliation: Laser Zentrum Hannover e.V. (LZH), Hollerithallee 8, 30419 Hannover, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Wesling
authors.affiliation: Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Krettek
authors.affiliation: Orthopaedic Department, Hannover Medical School (MHH), Anna-von-Borries-c 1-7, 30625 Hannover, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Hurschler
authors.affiliation: Orthopaedic Department, Hannover Medical School (MHH), Anna-von-Borries-c 1-7, 30625 Hannover, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Krämer
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000627:therapeutic use; D001860:Bone Plates; D004195:Disease Models, Animal; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D008297:Male; D009532:Nickel / Q000737:chemistry / Q000627:therapeutic use; D010027:Osteotomy / Q000295:instrumentation* / Q000379:methods; D011817:Rabbits; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D014025:Titanium / Q000737:chemistry / Q000627:therapeutic use
chemical_list: D001672:Biocompatible Materials; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium