Revascularisation during fracture healing with soft tissue injury.

INTRODUCTION: The purpose of our study was to quantitatively assess changes in the revascularisation process in the fracture gap and in adjacent regions during the course of healing of diaphyseal fractures with and without closed soft tissue injury.
METHODS: In a rat model (fracture n = 26; fracture with closed soft tissue crush n = 26) revascularisation was assessed in a long-term study with regional mapping by laser Doppler flowmetry, the healing outcome being mechanically tested after 4 weeks. Fracture and soft tissue crush were performed by modified controlled impact device.
RESULTS: No differences in blood circulation were observed at the fracture gap between the study groups up to day 28. In the proximal region of the fracture, the blood circulation in the group with additional soft tissue trauma was down to the baseline throughout the investigation period while the values in the fracture group led to a hyperperfusion after 3 and 7 days. In the distal part at day 1, the blood flow was strongly depressed after fracture, while microcirculation with an additional soft tissue trauma showed only a moderate decline. The reduction of blood circulation in the soft tissue corresponded to the extent of trauma. Mechanical testing demonstrated no significant difference in failure load or in flexural rigidity.
CONCLUSION: Our results indicate that damage severe soft tissue does not adversely affect the fracture healing process. Furthermore, the present findings suggest that a partly destroyed bone-soft tissue interaction resulting in only a temporary and slight reduction of the extraosseous blood supply might have no deteriorating effect on fracture healing outcome. A possible delay in healing is not observed during the first 4 weeks. Therefore, soft tissue damage without destruction of the bone-soft tissue interface is likely to have only a limited effect on fracture healing.