Bekler, H. | Bulut, G. | Usta, M. | Gokce, A. | Okyar, F. | Beyzadeoglu, T.
Article | 2008 | Acta Orthopaedica et Traumatologica Turcica42 ( 2 ) , pp.125 - 129
Objectives: This experimental study was designed to find new ways of improving stabilization of fractures in osteoporotic elderly patients through alterations made in the configuration and geometry of locked screw-plate fixation used in the conventional plate technique. Methods: Four screw configurations with varying angulations were used for plate-bone construction. Forty iron plates of high quality (100×35×3 mm) were divided into four groups and two screw holes, 3 mm in diameter, were drilled on each plate at a distance of 15 mm. In group A, the holes were drilled so that the screws would be vertically sent to the bone interface. . . .In the remaining groups, the holes were drilled for convergent (group B, 15°) and divergent (group C, 15°; group D, 30°) screw orientation. Screw-plate fixation was tested in a modified osteoporotic bone (Osteoporotic Generic Bone, Synbone) on an Instron materials testing system with an axial pullout force of 0.1 mm/sec. Failure loads were read from load-displacement curves and the type of failure was noted. Results: Screws placed in divergent orientations showed the highest axial pull-out strength (group C, 83.3 N/mm; group D, 80.8 N/mm), followed by convergent placement (72N/mm) and vertical placement (66.7 N/ mm). The type of failure was breakage of the bone sample in divergent configurations, and screw pull-out in convergent and vertical configurations. Conclusion: Divergent constructs may be a promising alternative to conventional screw placement in treating osteoporotic fractures. ©2008 Turkish Association of Orthopaedics and Traumatology