Affiliations: [a] Trauma Department, Hannover Medical School, Hannover, Germany | [b] Laboratory for Biomechanics and Biomaterials, Hannover Medical School, Hannover, Germany | [c] Laser Zentrum Hannover e.V., Hannover, Germany
Correspondence:
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Corresponding author: Christian W. Müller, Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Str. 1, 30625 Hannover, Germany. Tel.: +49 511 532 2050; Fax: +49 511 532 5877; E-mail:[email protected]
Abstract:
BACKGROUND: Inverse dynamization has recently been proposed for the
treatment of tibia non-unions. Nickel-titanium (NiTi) shape memory alloys
(SMAs) may provide an opportunity for contactless non-invasive alteration of
the stiffness of an implant after surgery OBJECTIVE: The aim of this pilot study was to analyze the feasibility of the
one way shape memory effect in a large animal as well as the feasibility of
our ovine large animal fracture model. METHODS: A tibia osteotomy was performed in three sheep, followed by NiTi
plate osteosynthesis in two cases and standard locking compression plate
(LCP) osteosynthesis in one sheep. Contactless induction heating was
performed after 3 weeks in order to alter the stiffness of the NiTi plates.
Euthanasia was followed by biomechanical analysis after 8 weeks. RESULTS: Successful change of configuration through contactless induction
heating was shown in both SMA plates by image intensifier control. Although
large differences in bending and torsional stiffness were observed between
the operated and contralateral tibia, the sheep ambulated almost normally at
six weeks post-operative. CONCLUSION: We were able to trigger the one way shape memory effect which
non-invasively altered the stiffness of the plate osteosynthesis.
