Comparing outcomes following direct admission and early transfer to specialized trauma centers in open tibial fracture treatment: a systematic review and meta-analysis

A research protocol was established in accordance with the PRISMA standards (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) [19]. The search terms were designed to match all articles containing information on outcomes in the treatment of open tibial fractures in adults (16 years and older). A pre-selection in language was set to Dutch, German, and English. Experimental studies, studies on animals, and case reports were excluded.

In collaboration with a medical information specialist, we searched for records in MEDLINE, EMBASE, and the Cochrane library. The search was initiated in March 2020 and re-run in March 2023. Records were included from the first of January 1990 to the 20th of March 2023. A total of 4.057 records were exported to EndNote deduplication and article and abstract screening was done with Rayyan [20] (Fig. 1). Two authors screened all records independently. By cross-checking the references, three more articles were added.

Studies on the outcomes of open tibial fractures in relation to the center of treatment and inter-hospital transport were included if they contained any information on the clinical and/or functional outcomes. All types of open tibial fractures were included, with the exception of pathological fractures or underlying disease. Any final discrepancies in definitive inclusion were solved by a third senior author. Studies were excluded if they had no (separate) data on transferred patients, the cohort consisted of minors under the age of 16, included other fracture locations with inseparable data, they did not provide information on outcomes or circumstances or if no full text was available.

One reviewer independently extracted the data from the included studies. The extracted data were checked by a second investigator. The following data were obtained:

The results were reported according to the three main groups found in the records, i.e., directly admitted patients to a specialized center (DAP), directly transferred patients who received surgical management solely in a limb-reconstruction center (in the literature used for this study referred to as hot-transfer patients, HTP) and transferred patients in general (GTPs) who received initial management elsewhere or whose status is unknown. If studies included mixed cohorts and individual patient data were not reported, the authors were first contacted by email to request the above-mentioned data. If the additional information was not obtainable, and we were not able to calculate the data from available data points, the article was excluded.

The risk of bias in the included studies was evaluated with the “Newcastle–Ottawa Quality Assessment Form for Cohort Studies” [21]. In this tool, eight questions are divided into the sections “selection”, “comparability” and “outcome”. Each question can be rewarded with a star; in the section “comparability”, a maximum of two stars can be rewarded. The total number of stars in each section correlates to a final assessment of quality as; poor, fair, or good. An article can earn a maximum of nine stars.

The search strategy is presented in a PRISMA diagram (Fig. 1). Nine studies met the inclusion criteria of this systematic review, published between 2005 and 2018. An overview of the study characteristics is summarized in Table 1.

In total, 520 patients were included with 526 fractures. The average age of the included patients was 46.9 years (17–98 years), with the minority being female (37.4%). The majority were GA type III open fractures (N = 441, 83%), and 88% (N = 387) were reported as type IIIB. Seven articles reported the GA grade for separate admission groups (Fig. 1). Pooled analysis suggests that the risk of direct admission compared to transfer for GA type III open tibial fractures might not differ (RR, 0.98; 95% CI 0.91–1.06; p = 0.62; participants, 435; I² = 85%). Road traffic accidents were the overall predominant cause of injury (58.2%), followed by falls in 28.8%. Patient details are listed in Table 2.

The overall quality evaluation of the articles was assessed as poor, although the assessment varied between five and nine stars (Table 2). The studies mainly qualified as poor due to a low score in comparability. Only one article scored stars in this section by adjusting their outcomes for general confounders such as age or specific confounders like the injury severity score. Most articles stated that there was no statistically significant difference in age and sex between the two cohorts, but this is insufficient to establish comparability according to the “Newcastle–Ottawa Quality Assessment Form for Cohort Studies” between outcomes. Despite the overall poor outcome, the studies scored high on patient selection, showing that the preferred study population was represented well. All studies reported on the ascertainment of exposure and demonstration of the outcome, also eight out of nine scored on the representativeness of the cohort. In addition, little to no bias was found while assessing study outcomes, as demonstrated in Table 5.

The alternative to direct admission is transferring stable patients as (“hot transfers”) after first admission in a non-MTC without initial surgical management. As there is no need to perform a first debridement in non-severely contaminated wounds within six hours, this could reduce overcrowding and potentially unnecessary, costly level I treatment [38]. Using photographs during primary clinical treatment can aid decision-making for tertiary referral. Primary debridement can be performed, after which the most appropriate treatment pathway is planned by the limb reconstruction unit receiving the referral. There is, however, a delicate balance between waiting to transfer and initiating treatment. A study conducted in 2019 compared two cohorts with open tibial fractures who received final soft tissue coverage within and after seven days. Of the 672 included patients, two-thirds received final treatment after seven days. Compared to the early group, the risk of developing complications (deep infection, osteomyelitis, and amputation) increased significantly. Thus, it is important to evaluate timely debridement and time till soft tissue coverage as two separate concepts, as the latter calls for an orthoplastic team with allocated OR time and personnel, taking up substantial OR time when free tissue transfer is required. These numbers show that regular transfers need more interventions. These additional interventions include fracture re-fixation, further debridement due to infection, and secondary treatment of nonunions or malunions [12].

The main strength of this review was its narrow focus and comprehensive search. However, several limitations exist. One limitation is that the included articles did not provide sufficient information on the transfer process. Reasons for transfer are not listed, and information such as AO fracture classification distribution, comorbidity, and other injuries is often not mentioned. Moreover, the studies were of overall poor quality according to the NOS—quality assessment scale, with the majority not correcting for confounders such as age or injury severity score (ISS). The level of comparability can create bias on a clinical selection and indication level, as there was no tool to determine the ISS of the cases transferred and directly admitted. This was especially significant in the HTP group, as injury severity plays a vital role in the ability to treat and transfer. The HTP group was also smaller, with only two articles, partially due to inseparable data. A systematic review performed in 2019 on the outcomes of tibia fractures has already brought this problem to light and stated that “there was considerable heterogeneity and lack of detail in the description of the simplest outcomes, such as union, infection, or reoperation” [39]. However, we were able to review the treatment and patient outcomes for transferred versus directly admitted patients. We specified the available results according to the delay in transfer, before or after primary surgical treatment. The results show the differences in clinical outcomes between the groups and shed light on the potential risks of (late-) transfer. Further prospective population-based studies that address the reasons for transferring and correlate patient outcomes to patient characteristics, treatment details, and hospital levels are needed.