Our study objective is that the DCO strategy in the management of fractures due to ballistic trauma is efficient, with a consolidation rate > 80% and a relatively low percentage of general complications. These complications had minor severity, and they were easy to manage.
Local complications, mainly sepsis on osteosynthesis material and pseudarthrosis, had relatively low rates. Our analyses showed that they were associated with several parameters. These parameters can be divided into nonmodifiable risk factors, such as a history of smoking, wound opening, fracture comminution, and bone loss. Modificable risk factors are mainly the delay of conversion from external fixation to internal osteosynthesis. The local complication rate was lower when this delay of conversion was shorter.
Our study is distinguished by strict inclusion and exclusion criteria. It was carried out in an institution that has good experience in the field of ballistics. Its protocol was interested not only in the results of the DCO strategy but also in the parameters that could affect this strategy. However, our study also has some limitations, mainly a selection bias due to its retrospective nature and the relatively small number of patients.
DCO is a relatively new concept (3) adopted in the management of ballistic limb trauma and appears to solve the defects of an older approach, which consists of early stabilization of skeletal lesions called early total care.
Early total care was the principal strategy for the management of polytrauma and war wounded in the 1980s and 1990. However, recent studies have shown that adoption of this strategy in groups of patients with hemodynamic instability is more associated with significant complications such as pulmonary embolism and acute respiratory distress syndrome and multiple organ dysfunction syndrome. This was exceptionally observed in intramedullary femur nailing (4). Studies have associated the occurrence of these complications with changes in pro-inflammatory markers (5). Indeed, the initial accident causes inflammatory and immunological reactions proportional to the severity of the trauma called the “first hit” (6). This reaction is characterized by local and systemic proliferation of various pro-inflammatory mediators, such as cytokines, complement, coagulation proteins and others. In addition, the prolonged duration of the surgery and bleeding lead to another significant inflammatory and immunological reaction called “Second Hit”. This second hit potentiates the effect of the first hit, and this may lead to a severe consequence in patients.
From these observations, a new strategy, based on minimizing the impact of the second hit by shortening the initial operating time and delaying the definitive treatment, was adapted to manage limb ballistic trauma. This strategy was called the DCO. Therefore, the treatment of long bone fractures of soldiers wounded on the battlefield is based on temporary external fixation, whose objective is controlling haemorrhage, restoring perfusion of the limb, debridement of necrotic soft tissue and ensuring bone stability. Additionally, without disturbing resuscitation care measures (7).
However, after hemodynamic stabilization, control of inflammatory phenomena and improvement of the local wound condition, this external fixation would be better converted into internal osteosynthesis. Although external fixation does not always allow anatomical reduction, it is often associated with a high rate of pin-site infection and low-quality bone callus. Respet et al attempted to determine the time between the realization of external fixation and the onset of pin site infection. They found that pin bacteriological cultures were positive in 50% of the cases in 2 weeks and 67% in 4 weeks (8). These results were also confirmed later by Clasper et al. (9). Additionally, Sigurdsen et al (10, 11) experimented on rats. To study the quality of the bone callus after an osteotomy, the callus was initially treated with an external fixator and then converted to internal synthesis with different delays. This conversion delay was seven days in the A group, 14 days in the B group, 30 days in the C group and control group D without conversion. All the groups had better consolidation than the control group, but only group A had a significant difference. Biomechanically, the rigidity and quality of the callus in group A were better than those in the other groups.
These studies not only show the interest of the conversion from external fixation to internal osteosynthesis but also prove the interest of the delay of this conversion. The shorter it is, the better the quality of bone callus, and the lower the risk of pin site infection and sepsis. This result is consistent with our study, which objectified that the delay of conversion is a risk factor for both septic and non-union complications.
In our study, this conversion time was relatively short compared to other papers in the literature(12–15). Care aimed at accelerating different phases of the wound healing process and fighting infection was possible. Indeed, VAC therapy allows a permanent elimination of exudates from the wound bed. Associated with repetitive debridement, it accelerated the inflammatory phase of the wound healing process. Hyperbaric oxygen therapy improves tissue oxygenation. Additionally, it enhances fibroblast and collagen synthesis, neovascularization, and the closure of arterial-venous shunts (16), which shortens the time to granulation formation, especially in open wound fracture Gustillo III (17). Additionally, several studies have proven the effect of VAC therapy to accelerate granulation tissue formation (18–20). With normal haemoglobin and serum protein levels, they hasten the proliferative phase of wound healing. Furthermore, in addition to adapted antibiotic therapy, hyperbaric oxygen therapy and VAC therapy had a confirmed role against infection.