[Evaluation of biomechanical rigidity of K-wire configurations in transverse osteotomies: a comparison of four-point bending test results].

Objectives: Four-point bending test was performed in transverse osteotomies of chicken humerus in order to assess biomechanical rigidity of fixation techniques that are commonly used in transverse unstable fractures of the tubular bones of the hand.

Methods: Thirty chicken humeral bones were transversely osteotomized and then randomly assigned to six fixation groups equal in number. Osteotomized bones were fixed with the use of two crossed (2 groups) or intramedullary (2 groups) K-wires; in the remaining two groups, crossed K-wires were used in combination with tension band wiring. The sizes of the crossed and intramedullary K-wires were 0.035-inch and 0.045-inch in paired groups, respectively. Biomechanical rigidity was measured by four-point bending test on an Instron testing machine.

Results: The most rigid configuration was obtained with 0.045-inch K-wires, followed by 0.035-inch K-wires used in combination with tension band wiring. These techniques provided significantly increased rigid fixations than those obtained by non-supplemented crossed and intramedullary K-wire fixations.

Conclusion: In the transverse fractures of the tubular bones of the hand, dorsally applied tension band wiring around two crossed K-wires provides adequate rigidity that allows early active motion in the postoperative period.