Acta chirurgiae orthopaedicae
et traumatologiae Čechoslovaca

Acta Chir Orthop Traumatol Cech. 2011; 78(3):208-214 | DOI: 10.55095/achot2011/033

Použití cerkláže pro usnadnění hojení zlomenin. Biomechanická studie způsobu dotahování drátěné smyčkyPůvodní práce

D. WÄHNERT^1,*, M. LENZ¹, U. SCHLEGEL¹, S. PERREN^2,3, M. WINDOLF¹

¹ AO Research Institute Davos, Davos, Switzerland

² AO Foundation Davos, Davos, Switzerland

³ Institute for Health and Biomedical Innovation (IHBI), Queensland University of Technology, Queensland, Australia

PURPOSE OF THE STUDY:
Twisting is clinically the most frequently applied method for tightening and maintaining cerclage fixation. The twisting procedure is controversially discussed. Several factors during twisting affect the mechanical behaviour of the cerclage. This in vitro study investigated the influence of different parameters of the twisting procedure on the fixation strength of the cerclage in an experimental setup with centripetal force application.

MATERIAL AND METHODS:
Cortical half shells of the femoral shaft were mounted on a testing fixture. 1.0 mm, 1.25 mm and 1.5 mm stainless steel wire cerclages as well as a 1.0mm cable cerclage were applied to the bone. Pretension of the cerclage during the installation was measured during the locking procedure. Subsequently, cyclic testing was performed up to failure.

RESULTS:
Higher pretension could be achieved with increasing wire diameter. However, with larger wire diameter the drop of pretension due to the bending and cutting the twist also increased. The cable cerclage showed the highest pretension after locking. Cerclages twisted under traction revealed significantly higher initial cerclage tension. Plastically deformed twists offered higher cerclage pretension compared to twists which were deformed in the elastic region of the material. Cutting the wire within the twist caused the highest loss of cerclage tension (44% initial tension) whereas only 11 % was lost when cutting the wire ends separately. The bending direction of the twist significantly influenced the cerclage pretension. 45% pretension was lost in forward bending of the twist, 53% in perpendicular bending and 90% in backward bending.
CONLUSION
Several parameters affect the quality of a cerclage fixation. Adequate installation of cerclage wires could markedly improve the clinical outcome of cerclage.

Klíčová slova: biomechanics, cerclage wire, cerclage cable, cerclage, periprosthetic fractures

Zveřejněno: 1. červen 2011  Zobrazit citaci