[Comparative biomechanical studies of conventional and self-tapping cortical bone screws].
In normal cortical screws the thread must be cut by a separate thread-cutter. So a high stability of the connection is achieved. On the other hand thread cutting needs time, which may be assumed to several minutes during a plate osteosynthesis. To avoid thread-cutting, self-tapping screws were used 20 years ago. These old self-tapping screws had a reduced stability and a lower torque at the final screw driving so that they tended to destroy the thread. By a modification of the cutting edges at the tip of the screw the tapping quality is increased decisively. The microscopic examination showed a better cutting of the new screws with little difference to a thread-cutter. In biomechanical tests the final torque and the maximum tension force of the self-tapping screws were at the same level as in usual pre-cut screws. In the practical use the new self-tapping screws have a good handling and save time during operation. In osteoporosis, they should be used carefully in order to meet the opposite corticalis' hole and not to destroy the ipsilateral corticalis' thread.
Hess
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T
Orthopädischen Universitäts- und Poliklinik Homburg/Saar.
Hopf
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T
Fritsch
E
E
Mittelmeier
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H
D001696:Biomechanical Phenomena; D001863:Bone Screws; D001842:Bone and Bones / Q000601:surgery; D006801:Humans; D013499:Surface Properties; D013718:Tensile Strength
Biomechanische Vergleichsuntersuchungen über herkömmliche und selbstschneidende Kortikalisschrauben.