Morphological and biomechanical effects of vitamin K2 on fracture healing: An animal study on the rat tibia fracture model.

Objective: The aim of this study was to evaluate the effects of vitamin K2 on fracture healing.

Methods: Twenty-four 6-week-old male Wistar albino rats that had open tibia fractures induced were included in this study. They were divided into 2 groups of 12, a group that had vitamin K2 administered over 30 consecutive days and a control group. After 30 days, the rats were sacrificed, and from each group, 6 tibiae were selected for biomechanical testing to examine the mechanical strength of the callus tissue using the Instron 3-point bending test and 6 tibiae were selected for histological analysis to examine the density and organization of callus tissue using Allen's grading system and Huo et al's grading system. Furthermore, weekly x-rays were taken to evaluate bone union described by Lane and Sandhu, and osteocalcin, procollagen I N-terminal propeptide, and procollagen I C-terminal propeptide were examined in blood samples taken by intracardiac puncture during sacrification.

Results: Breaking force (P = .047), breaking time (P = .019), stiffness (P = .039), fracture strength (P = .041), and Young's modulus (P = .032) showed a statistically significant increase in the K2 group. Procollagen I C-terminal propeptide (P = .024), procollagen I N-terminal propeptide (.047), and osteocalcin (.048) levels were significantly higher in the K2 group compared to the control group. Furthermore, 3rd-week x-rays showed higher bone union scores according to the Lane and Sandhu method in the K2 group (P = .014). However, the histological grading systems of Allen and Huo et al did not show statistically significant differences between groups (P = .086, P = .07, respectively).

Conclusion: In light of these findings, it could be concluded that vitamin K2 has a significant positive effect on fracture healing.