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Postoperative Infection In Patients Undergoing Orthopedic Damage Control Using External Fixation

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Post-Operative Infection. Objective: To carry out a retrospective analysis of cases submitted to orthopedic damage control in a teaching hospital orthopedic emergency room with the aim of evaluating patients with postoperative infection after being converted to internal osteosynthesis. Methods: Retrospective analysis of patients from June 2012 to June 2013 undergoing orthopedic damage control with an external fixator that were later converted to definitive osteosynthesis, with a rod or plate. Results: We found an infection rate of 13.3% in our sample and verified technical errors in the preparation of the fixator in 60.4% of opportunities.Conclusion: An infection rate was found that we consider high, as well as inadequacies in the construction of the external fixator. We emphasize that this procedure is not without risk and training for doctors who perform it must be mandatory.

Postoperative infection in patients undergoing orthopedic damage control using external fixation

a Department of Orthopedics, Santa Casa de São Paulo, São Paulo, SP, Brazil
b Orthopedics and Traumatology Service, Hospital Israelita Albert Einstein, Federal University of São Paulo (Unifesp), São Paulo, SP, Brazil
c Institute of Orthopedics, Hospital das Clínicas, Faculty of Medicine, University of São Paulo (USP), São Paulo, SP, Brazil
d Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brazil

Introduction

Damage control in orthopedics is a surgical tactic recommended for polytraumatized patients or those with severe soft tissue injuries, as recognized in the literature.1However, this procedure is not without risks. Local and systemic complications associated with external fixation for damage control2 have been reported, and one of them is bone infection. Studies show infection rates in pin tracts ranging from 0.5 to 30%.

Bacterial contamination and infection in the path of external fixator pins are relatively common and conversion to internal osteosynthesis, whether with intramedullary nails or plates, in the presence of such a condition, can lead to serious complications, local and/or systemic.4The frequency of this association of events is not clear in the literature.

The correlation between infection in the path of external fixator pins and post-traumatic osteomyelitis after internal osteosynthesis, which constitutes chronic infection of the locomotor system, is well established.

Infection at the bone-fixator pin interface has been proven to be directly associated with the insertion technique, stability and position in the limb, during pin placement, by establishing tension or not in the soft parts. The presence of these factors contributes to infectious complications after conversion to definitive internal osteosynthesis, whether intramedullary nail or plate.

The objective of our work is to identify in patients undergoing control of musculoskeletal damage admitted to the emergency room for one year, the quality of reduction and fixation and the frequency of bone infection after definitive treatment.

Casuistry and methods

This work was duly submitted to and approved by the institution’s Ethics Committee and is registered under protocol CEP no. 624.307.

We retrospectively evaluated 120 patients who underwent external fixation to control musculoskeletal damage from June 2012 to June 2013 and were treated at the time of emergency in the emergency room of the Department of Orthopedics and Traumatology at our institution.

In this retrospective study, we included patients who underwent damage control surgery using external fixation that

after conversion to definitive osteosynthesis, they developed infection.

Patients who presented infectious complications due to local systemic changes, such as vasculopathies, diabetes mellitus or consumptive disease, and patients with psychiatric disorders that may have impaired the development or care of the fixator in any way were excluded.

All radiographs were generated in digital form and analyzed using the Impax program. The distances between Schanz holes and pins until the definitive synthesis were analyzed in the program itself. We sought to identify the presence of technical errors during drilling (characterized by multiple perforations) or subjective analysis carried out by three different groups of two evaluators. One group was made up of assistant doctors with at least five years of experience in orthopedic trauma, another with two third-year residents and another with two second-year orthopedic residents. The evaluators were named (table 1):

Tabela 1
Tabela 1

– Evaluator 1: assistant with more than five years of experience

– Evaluator 2: assistant with more than five years of experience

– Evaluator 3: third year resident

– Evaluator 4: third year resident

– Evaluator 5: second year resident

– Evaluator 6: second year resident

Postoperative infection was characterized by clinical examination, during hospitalization or during outpatient investigation, based on data recorded in the medical records. The following clinical criteria for infection were considered: erythema, hyperemia or fistula in the path of the pins or surgical incision (fig. 1).

During external fixation, prior drilling with a drill and manual insertion of the pins were always respected.

Figura 1.
Figure 1.

In no case did we have a pin in the fracture exposure zone.

In evaluating the radiographs, we observed the pre- and post-operative exams, we measured the position and distance of the Schanz pins in relation to the definitive synthesis, the presence of perforations in a greater number than the pins installed as this suggests difficulty and additional damage in installing the external fixator, presence of osteolysis in the holes for the Schanz pins and if the place where the pins were drilled caused problems for definitive internal fixation. Among these, we evidence postponed surgery due to infection in the pin path, changes in the surgical incision for definitive osteosynthesis and unplanned surgical procedures for reassembly of the fixator due to unstable assembly.

The average conversion time from external fixators to definitive osteosynthesis was evaluated by retrospective analysis of medical records.

Results

Of the 120 patients who underwent damage control, 16 (13.3%) suffered post-traumatic osteomyelitis after definitive synthesis. In these 16 patients, we were able to directly relate it to definitive internal osteosynthesis, as there were no signs of local infection after external fixation in the urgency.

The average age of these 16 patients was 43.4 years, ranging from 19 to 81. We observed a predominance of males, with 13 patients (81.2%), and the remaining three (18.8%) females.

Regarding the external fixator conversion time for definitive osteosynthesis, the shortest period was five days and the longest was 30. We had an average of 15 days for the final conversion.

Infection occurred in eight isolated leg fractures (50%), two patients with fractures of the femur and ipsilateral tibia (floating knee), two (12.5%) with ankle fractures (12.5%), two (12.5%) %) with a tibial plateau fracture, one (6.2%) with an isolated femur fracture and one (6.2%) with a humeral fracture.

Of the 16 patients with post-traumatic infection, 37.5% of the time (six patients) occurred after closed fractures and in 62.5% (10) after Gustillo grade 3 A open fractures (table 2).

In 62.5% (10 patients) the fixator was mounted transarticularly and in the remaining six (37.5%) it was monostolic with monolateral configuration, with tube-to-tube connection.

As for the etiological agent, it was adequately identified in 10 patients (62.5%) of the 16 infected, in a third of these there were multiple bacteria and there was a need for surgery to clean, debridement and curettage of the pin hole path. The polymicrobial findings found in intraoperative cultures were: Staphylococcus aureus, coagulase-negative Staphylococcus, Klebsiella sp, Acinetobacterbaumanni and Pseudomonas aeruginosa.

Regarding the objective assessment of multiple bone perforations, we observed a greater number than pins used in eight patients (50%) of the 16 patients infected after definitive osteosynthesis (fig. 2).

Figura 2
Figure 2

When we measured the distance between the position of the Schanz pin and that of the osteosynthesis, we obtained an average of 2.2 cm, with a variation of up to 6 cm. In seven cases (43.8%) of the 16 infected people, the distance measured was 0 cm, two between 1 and 2 cm, two between 3 and 4 cm, one between 4 and 5 cm, three with 5 cm and one with 6 cm (table 2). Regarding the evaluation of the quality of fixation and reduction, we were able to observe that of the 16 cases, in four (25%) the six evaluators agreed, in two the fixation was considered adequate and in the other two inadequate; in five cases (31.3%) five evaluators agreed on the quality of the evaluation, in two it was considered adequate and in three inadequate; in four cases (25%) four evaluators agreed with the evaluation, all were considered inadequate; In three cases (18.7%) there was no agreement between the evaluators, three considered the fixation and reduction to be adequate and three others to be inadequate (table 3).

In the 13 cases (81.2%) in which there was some agreement (adequate or inadequate), it was considered adequate in four (30.8%) and inadequate in nine (69.2%).

When analyzing the evaluations, we obtained 96 evaluations, which were considered adequate in 38 cases (39.6%) and inadequate in 58 cases (60.4%). When analyzing the evaluations of each evaluator, we obtained for evaluator one: five cases (31.3%) evaluated as adequate and 11 (68.7%) as inadequate; assessor two: 10 cases

When we separately evaluated orthopedists with more than five years of experience, we obtained 32 evaluations, 15 (46.9%) were considered adequate and 17 (53.1%) were considered inadequate (table 4). In this group, there was agreement in the quality of fixation and reduction in nine cases (56.3%) and non-agreement in the remaining seven (43.7%), of the nine cases with agreement in four (44.4%). ) the quality of reduction and fixation was considered adequate and in five (55.6%) inadequate.

When we evaluated third-year residents separately, we obtained 32 evaluations, 14 evaluations (43.7%) were considered adequate and 18 (56.3%) were considered inadequate (table 4). In this group, there was agreement on the quality of reduction and fixation in nine cases (56 .3%) and non-agreement in the remaining seven (43.7%), of the nine cases with agreement in four (44.4%) the reduction and fixation was considered adequate and in five (55.6%) inadequate.

When we evaluated second-year residents separately, we obtained 32 evaluations, nine (28.1%) were considered adequate and 23 (71.9%) were considered inadequate (table 4). In this group, there was agreement on the quality of reduction and fixation in 13 cases (81.3%) and non-agreement in the remaining three (18.7%), of the 13 cases with agreement in three (23.1%), reduction and fixation were considered adequate and in 10 (76.9%) inadequate.

When observing the assessments considered adequate, we can see a tendency towards similar assessments between assistants and third-year residents, but a lower assessment of cases considered suitable for second-year residents (table 5).

When we compared the cases in which the assistants agreed with the third-year residents’ assessment, we observed that there was agreement in five (31.3%) of the 16 cases, in three the reduction and fixation was considered adequate and in two inadequate. Of the remaining 11 cases, in four, despite the agreement of the assistants’ assessment, there was no agreement with the third-year residents; in one case, the reduction and fixation was considered adequate by the assistants and in three cases, inadequate.

When we compared the cases in which the assistants agreed with the assessment of the second-year residents, we observed that there was agreement in seven (77.8%) of the nine cases, in two of these the reduction and fixation was considered adequate and in five inadequate. In one case where there was agreement from the assistants (considered adequate) the second year residents considered it inadequate.

When evaluating the seven cases in which there was no agreement among assistants with more than five years of experience, we observed that in one case the residents, whether third or second year, also did not agree. In four cases, the two third-year resident evaluators also did not agree and in three cases the two third-year resident evaluators agreed and considered the reduction and fixation inadequate. Of the seven cases in which the assistants did not agree, the second-year resident evaluators considered the reduction and fixation adequate in one case and inadequate in four.

Discussion

External fixators, more versatile fixation devices that allow different types of assemblies and configurations, can be placed quickly, are applied in the treatment of fractures in urgent and emergency situations (damage control) and in a percutaneous, with less damage to soft tissues.

This procedure, both provisional and definitive, is still routine in many services and varies from 32 to 89% of the choice of a group of orthopedists in a previous study.9However, this procedure is not without risks.

In our sample, we found a frequency of 13.3% of infection after the use of an external fixator for damage control. Although compatible with literature data, which range from 0.5 to 30%,2,3 we are concerned with judging this rate very high among the possible complications.

The first issue always remembered when searching for the etiology of the infection is the environment in which the treatment takes place, in our case a teaching hospital. It seems like a weak cause-and-effect correlation, because the procedure is considered to be of little complexity and there was at least one doctor with three years of training on the surgical team.

Another factor that is involved in the complication of infection after internal osteosynthesis is infection of the Schanz pin tract. In our patients, the presence of clinical suspicion of infection was an indication to exchange the pin for installation in another location or to continue treatment with osteosynthesis using the external fixator.

Reduction and fixation were considered inadequate in 60% of evaluations, a value considered very high, and on average, assistants and third-year residents found reduction and fixation adequate in only 50% of evaluations. This shows that there is a need for better teaching in the treatment of emergency situations with external fixators.

External fixation is often neglected in our environment both in its preoperative planning, procedure and subsequent care. In any external fixation procedure, the future definitive synthesis must always be considered when assembling the fixator and placing the pins. This situation should always be discussed with the attending physician, who can make a pre-operative schedule with a view to future synthesis, whether plate or rod. In our study, in 43.8% of cases, the location of the Schanz pin was not far from the definitive osteosynthesis.

The correct technique for inserting the pin, care with the dressing and the surgical wound are essential to prevent these complications.9,10Pre-drilling, manual insertion of the pins, use of the safety corridor are factors that cannot be forgotten during the fixation. The systematization of this intra- and post-operative care is a factor that we found capable of control by the doctor to influence the infection rate of the Schanz pin path in damage control.

Routinely, the quality of fracture reduction is not so important to consider postoperative infection, since the use of the external fixator is temporary.8 However, in some situations in which the fixator remains in place for a prolonged time, this factor must be taken into account. In our series, the longest period for conversion was 30 days and the temporary reduction is important for stabilizing the condition, local care and general condition.

In our cases, we observed that all of them had a safety event respected in the analysis of the radiographs (in our case series, no neurovascular lesions were observed).

When we identified the importance of the quality of the installation and spatial assembly of external fixators, we asked doctors with different training periods to judge the quality of the assembly and look for signs of technical inadequacy in the x-rays in the files, which occurred 60% of the time in our study, value considered very high.

Regarding the frequency of bone infection post-damage control, we confirmed that of the 13% infected, 50% identified the presence of error or technical inadequacy that may have contributed to the undesirable outcome./p>

When considering external fixator assemblies, we cannot correlate the frequency of infection with a given type of assemblage. There was a prevalence of transarticular assemblies, used in metaepiphyseal fractures, ipsilateral bone fractures and extensive soft tissue injuries to avoid post-traumatic joint deformities (62.5% of cases).

Although it was not possible to correlate infection after internal osteosynthesis and the use of fixators to control damage, the presence of inadequacy in assemblies in the emergency room suggests the possibility and need for training and rules for their use and assembly.

Conclusion

Bone infection occurred in 13.3% of cases treated with control of musculoskeletal damage after internal osteosynthesis. In these cases, reduction and fixation was considered adequate in 39.6% of evaluations and inadequate in 60.4%. We emphasize that this procedure is not without risk and training for doctors who perform it must be mandatory.

Interest conflicts

The authors declare no conflicts of interest.

Interest conflicts

The authors declare no conflicts of interest.

REFERENCES

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Author: Prof. Dr. Pedro Péricles Ribeiro Baptista

 Orthopedic Oncosurgery at the Dr. Arnaldo Vieira de Carvalho Cancer Institute

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