The Study Of Application Of Damage Control Orthopedics (DCO) In Managing A Model Of Severe Injury

Objectives: To compare the biological and histological changes induced by different strategies in managing a model of bilateral femoral fractures associated or complicated with shock, and to further explore the necessity for Damage Control Orthopedics (DCO) for this type of injury.Methods: Randomized, controlled study of experimental models. Thirty-six male New Zealand white rabbits were divided into three groups. A carotid artery catheter was connected to a multi-channel biologic recorder for monitoring vital signs and sampling blood in each animal of the three groups. Then, a model of bilateral femoral shaft fractures associated with shock was made. Two hours after resuscitation, a reamed intramedullary nailing fixation was performed in the first group (ETC group), and an external fixation device applied in the second group (DCO group), the fractures in the third group (CON group) were supported with splints only as a control group. Thirty six hours after the procedures in three groups, the animals were killed for histological evaluation. Changes of the mean arterial pressures (MAP), respiratory rate (RR), heart rate (HR), inflammatory mediators (IL-6, IL-10, TNF-α) concentration, and histological appearance of main organs after the procedures were compared and analysed between the groups. Results: A decreased MAP and RR and an increased HR were found after the procedures in all three groups. However, compared to the DCO group and CON group, the extent of these changes in ETC group was most significant (P < 0.05). Plasma concentrations of IL-6, IL-10 and TNF-αall presented with a peak followed by a gradually postoperative decrease in three groups. The exaggerated levels of these mediators demonstrated a significant difference between all the groups. The level was much greater in the ETC group and hence the statistical difference much more significant when compared with the other two groups (P < 0.05). As to histological appearances, the statistical difference varies from organ to organ. There is highly significant difference when the ETC group and DCO group is compared with the CON group as far as lungs are concerned (P <0. 01), although there is no statisticl different between the ETC group and DCO group, the number of abnormal histological appearances in ETC group is more than DCO group 3. As to the liver, there is only significant difference between the ETC group and the CON group (P <0.0001), and not between the DCO group and CON group (P >0.05). In terms of kidney and heart, there is no significant difference cross the groups(P >0.05).Conclusions: In this animal experiment on models of bilateral femoral fractures associated with shock, an early reamed intramedullary nailing fixation procedure resulted in more adverse effects on vital signs, inflammatory response and multiple organs. The injuries also cause histological damages to lungs and liver. Therefore, early reamed intramedullary nailing fixation may pose a potential risk of developing complications and adopting the DCO strategy may be more preferable.