Electromagnetic induction heating of an orthopaedic nickel--titanium shape memory device.
Shape memory orthopaedic implants made from nickel-titanium (NiTi) might allow the modulation of fracture healing, changing their cross-sectional shape by employing the shape memory effect. We aimed to show the feasibility and safety of contact-free electromagnetic induction heating of NiTi implants in a rat model. A water-cooled generator-oscillator combination was used. Induction characteristics were determined by measuring the temperature increase of a test sample in correlation to generator power and time. In 53 rats, NiTi implants were introduced into the right hind leg. The animals were transferred to the inductor, and the implant was electromagnetically heated to temperatures between 40 and 60°C. Blood samples were drawn before and 4 h after the procedure. IL-1, IL-4, IL-10, TNF-α, and IFN-γ were measured. Animals were euthanized at 3 weeks. Histological specimens from the hind leg and liver were retrieved and examined for inflammatory changes, necrosis, and corrosion pits. Cytokine measurements and histological specimens showed no significant differences among the groups. We concluded that electromagnetic induction heating of orthopedic NiTi implants is feasible and safe in a rat model. This is the first step in the development of new orthopedic implants in which stiffness or rigidity can be modified after implantation to optimize bone-healing.
Müller
Christian W
CW
Trauma Department, Hannover Medical School MHH, Carl-Neuberg-Str 1, D-30625 Hannover, Germany. mueller.christian@mh-hannover.de
Pfeifer
Ronny
R
El-Kashef
Tarek
T
Hurschler
Christof
C
Herzog
Dirk
D
Oszwald
Markus
M
Haasper
Carl
C
Krettek
Christian
C
Gösling
Thomas
T
D000497:Alloys / Q000627:therapeutic use*; D000818:Animals; D001672:Biocompatible Materials; D055590:Electromagnetic Phenomena; D005264:Femoral Fractures / Q000628:therapy; D017102:Fracture Healing / Q000502:physiology; D006358:Hot Temperature; D007375:Interleukin-1 / Q000097:blood; D016753:Interleukin-10 / Q000097:blood; D015847:Interleukin-4 / Q000097:blood; D008297:Male; D009532:Nickel / Q000627:therapeutic use*; D019736:Prostheses and Implants; D051381:Rats; D011917:Rats, Inbred Lew; D014025:Titanium / Q000627:therapeutic use*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D000497:Alloys; D001672:Biocompatible Materials; D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; C040654:titanium nickelide; D016753:Interleukin-10; D015847:Interleukin-4; D009532:Nickel; D014025:Titanium