The treatment of recurrent infection after posttraumatic tibial osteomyelitis may need repeated debridement, prolong treatment time and even bring a huge burden to patients and society [14, 15]. However, research on the risk factors of recurrent infection after surgery is rare. Studies have showed that the infection recurrence rate after treatment of posttraumatic tibial osteomyelitis with bone defect can reached to 10–20% . In this study, infection recurrence rate in the treatment of post-traumatic tibial osteomyelitis by using Ilizarov technique was 11.4%, which was consisted with previously reported study , which also confirms that the Ilizarov technique is safe and effective treatment option in treatment of post-traumatic tibial osteomyelitis. This study shows that the number of previous operations (repeated operations), bone exposure, and Pseudomonas aeruginosa infection are risk factors for recurrent infection.
The important principle of eradication of osteomyelitis is to thoroughly and adequately debride the infected bone and soft tissues until there is a bit of bleeding active bone (paprika sign) ; the severity of the trauma, the patient’s immune status, and incomplete debridement are all possible to put patient at a high risk of additional surgery. According to our study, the number of previous operations (repeated operations) is a risk factor for infection reoccurrence of post-traumatic osteomyelitis, which is consisted to other studies results [19, 20]. First of all, repeated operations will prolong the hospital stay, additional damage to bone and soft tissue, increase pain to impaired limb function, which will affect the quality of life of patients . In addition, repeated operations may produce more scar tissue and affect the flexibility and blood supply of the soft tissues, which makes subsequent surgical exposure difficult, and even causes adverse outcomes such as recurrent infection . Therefore, carefully designing surgical treatment plans, performing limb reconstruction by experienced professional teams, and minimizing additional surgical operations have become particularly important in the treatment of post-traumatic osteomyelitis.
Studies have shown that the recurrence rate of osteomyelitis caused by Pseudomonas aeruginosa infection is 2 times higher compared with Staphylococcus aureus . Compared with any other isolated pathogens, the prognosis is poor, and it is positively correlated with amputation. Among the 17 cases of infection recurrence in this study, 9 cases of Pseudomonas aeruginosa (52.9%), 5 cases (29.4%) of Staphylococcus aureus (including MRSA); Pseudomonas aeruginosa infection rate was higher than other cases. Bacterial infections are mainly caused by the ability of Pseudomonas aeruginosa to form biofilms. It is also recognized as an important cause of chronic infections. Bacteria exist in aggregates wrapped in the extracellular matrix produced by themselves, which shows resistance to antibacterial drugs. Tolerance and drug resistance are difficult to eradicate with antibiotic treatment . Secondly, Pseudomonas aeruginosa has a protective effect in infection, and it has been proven that it can eliminate free radicals released by activated macrophages in vitro and prevent itself from being phagocytosed and cleared . Recent studies have suggested that Pseudomonas aeruginosa is directly related to the recurrence of post-traumatic osteomyelitis infection . In summary, in charge surgeon need to be alerted to patients with posttraumatic tibial osteomyelitis caused by Pseudomonas aeruginosa infection.
In this study, the bone exposure in cases with infection recurrence was as high as 88.2% (15/17), which strongly indicated that the complete coverage of soft tissue is of great significance for infection control and prevention. Early coverage of soft tissue can improve local blood supply, provide nutrition, eliminate dead space, promote local immune defense and the effectiveness of antibiotic administration . Therefore, while dealing with severe open fractures and thoroughly debridement to eradicate infection, the reasonable reconstruction of the surrounding soft tissue is still a very concern.
Our study showed that the course of osteomyelitis> 3 months, intraoperative blood transfusion, and diabetes are related factors for the recurrence of post-traumatic osteomyelitis infection. If post-traumatic osteomyelitis is not treated effectively in time, it may cause more serious infections over time, and even cause larger dead bones and deep soft tissue infection, laying hidden source for recurrent infection. A study analyzed the risk factors of 116 cases of recurrence of osteomyelitis infection, which concluded that the course of osteomyelitis> 3 months is directly related to the recurrence of osteomyelitis . In this study, 52.9% (9/17) of patients with recurrent infection received intraoperative blood transfusion, which was much higher than 22.7% (30/132) of the non-infection recurrence group. In an analysis of 192 patients with post-traumatic osteomyelitis, risk factors for recurrent infection were analyzed which showed that the risk of infection recurrence in patients receiving blood transfusion was 2 times higher , which is similar to our study. Another study proposed that the risk of multi-microbial infection in patients undergoing blood transfusion during orthopedic surgery is 2.15 times higher than that of patients without blood transfusion . Intraoperative blood transfusion may reflect the severity of the injury, the complexity of the operation and even the longer operation time. Therefore, more attention was given to patients with intraoperative blood transfusion. In this study, patients with diabetes accounted for 15.4% (23/149), 35.3% (6/17) in the infection recurrence group, and 12.9% (17/132) in the non- infection recurrence group. Tice and Lin et al. [30, 31] have confirm that diabetes is a related factor for the recurrence of osteomyelitis. Therefore, we recommend that blood glucose should be strictly controlled during the perioperative period and before the external fixator is removed after the operation in patients with posttraumatic tibial osteomyelitis accompanied with diabetes, and multidisciplinary cooperation with consultant to endocrinologists is strongly recommended.
Among 17 cases with recurrent infection, recurrence time of infection was shorter in non-operative group than operative group (p = 0.043), and all recurrent infection cases with Pseudomonas aeruginosa were underwent surgical intervention. Age, smoking, bone defect size, intraoperative flap coverage, bone transport level (single and double level), external fixator type (ring or monolateral), initial fixation type (internal fixation, external fixation), initial injury mechanism (open or close), laboratory tests (erythrocyte sedimentation rate, white blood cells, C-reactive protein) and other factors have no significant influence on the recurrent infection.