Comparison of the vascularity of fasciocutaneous tissue and muscle for coverage of open tibial fractures.

Background: Early coverage with vascularized soft-tissue flaps has dramatically improved the outcome in open tibial fractures. However, the ideal tissue for covering open fractures remains controversial. Several clinical studies suggest that muscle is superior to fasciocutaneous tissue; this is attributed to the presumed higher vascularity of muscle, although experimental evidence is inconclusive. The authors' previously described novel murine fracture model, which allows exclusive comparison of both tissues, demonstrated enhanced healing beneath muscle. The present study was undertaken to compare the vascularity of muscle and fasciocutaneous tissues over the course of fracture healing.

Methods: Two experimental groups comprised mice with tibial fractures in contact with either muscle or fasciocutaneous tissues exclusively. Controls included a nontrauma group and those where soft tissues and periosteum were dissected but the tibia was not fractured. Animals were harvested between 3 and 28 days after fracture (n = 170 in total). The vascular density of the soft tissues was assessed using immunohistochemical techniques.

Results: Fasciocutaneous tissue was found to have a higher vascular density compared with muscle in contact with the fracture site at all time points (p < 0.0001, two-way analysis of variance), despite accelerated healing of fractures covered by muscle.

Conclusions: The authors' data show that the more advanced healing of fractures covered by muscle compared with fasciocutaneous tissue is not related to the vascularity of the tissues, as the latter had a higher vascular density at all time points. Therefore, provided that a flap has sufficient vascularity to effectively reconstitute the soft-tissue envelope, other factors may be important in specifically promoting fracture healing.