Background
Open tibial fractures account for over 40% of all open fractures and are frequently accompanied by significant damage to soft tissues, including skin, muscle, and neurovascular structures [
1]. These fractures are especially prone to serious complications, such as infection, malunion, and non-union, adding to the incidence of readmission and reoperation [
2,
3]. Thus, a timely and appropriate treatment protocol that involves thorough debridement, accurate reduction, early and stable fixation, repair of soft tissues, and administration of antibiotics has been widely accepted for reducing complications and increasing the chances of bony union [
2,
4].
The fixation methods for open tibial diaphyseal fractures have evolved over the years but remain controversial [
4‐
6]. Damage control orthopaedics (DCO) with external fixation followed by definitive internal fixation with nailing or plating is a popular strategy for significantly decreased complications [
7]. However, the secondary fixation procedure causes economic, physical, and psychological burdens, making the strategy less than ideal [
7‐
9]. Thus, external fixation is an alternative as the definitive fixation in some cases such as improper conditions of soft tissues or patients’ non-compliance for the staged surgeries. Nevertheless, based on relevant studies, external fixation as a definitive treatment should warrant more attention for possible issues related to pin-track infection, unsatisfactory alignment, and poor union, leading to unplanned secondary fixation procedures and consequent additional burdens to patients in physiology and economy [
5,
10‐
14].
To improve the performance of external fixation for treating such fractures, additional minimal internal implants, such as cortical screws and Kirschner wires, have been recommended [
14‐
18]. Nevertheless, the combined technique brings the concern for increased infection risk due to metal implants, especially in these open injuries. Relevant studies have been rarely reported, and there is a lack of reliable data regarding treatment outcomes. Therefore, the present study retrospectively compared the outcomes of the combined technique with simple external fixation to evaluate the effectiveness and safety of combined fixation in treating open tibial diaphyseal fractures.
Discussion
Simple external fixation used to treat open tibial shaft fractures is accompanied by a high incidence of complications in terms of reduction, alignment, and bone healing [
5,
10‐
14]. In a randomized and prospective study from Holbrook et al. [
13], 28 open tibial shaft fractures treated with simple external fixation had a fairly high rate of pin-track infection (21%), reduction loss (11%), malunion (36%), delayed union (21%), and non-union (11%). Henley et al. [
12], in a report on 70 patients with type II, IIIA, and IIIB open fractures of the tibial shaft, noted 17.1% delayed union, 4.3% non-union, 50.0% pin-track infection, and 31.0% malunion after external fixation. Moreover, 17.0% fractures underwent a change in fixation due to delay in healing or loss of reduction [
12]. Patients with simple external fixation also exhibited similarly high complication rates in our study. The incidence of changing the fixation system was as high as 34.1%, indicating the potential problems of simple external fixation in treating open tibial shaft fractures [
5,
10‐
14]. The biomechanical limitations of external fixation for adequate reduction and stability and premature removal of the fixator in the healing process were believed to be the leading causes [
5,
10‐
14].
Thus, in order to improve the biomechanical stability of the external fixation system, additional minimal internal apparatus, such as cortical screws, have been recommended for the management of open tibial diaphyseal fractures [
14‐
18]. As early as 1983, Spiegel et al. [
17] adopted the combined technique in several patients and believed that it could decrease pin-track infection, accelerate early weight-bearing, and enhance healing. However, detailed statistical data were not given in their report. Subsequently, Bach et al. [
15] conducted a prospective study of 59 patients with grade II or III open tibial shaft fractures to compare internal and external fixation. In the EF group, minimal internal fixation was also used to obtain and maintain anatomic reduction in 12 patients. Although they did not analyse the patients treated with combined fixation independently, the EF group showed decreased malunion (10%), changing fixation (7%), and non-union (none) [
15]. Despite some investigators advocating the combined technique in their reports [
14‐
18], no comparatively large series study exclusively aimed at open tibial shaft fractures has been reported. In our study, 67 patients with the combined technique were retrospectively analysed, providing relatively new and valuable data in this field.
First, the two therapies presented similar infection rates, indicating that the additional LIF did not lead to increased infection risks, even in Gustilo-Anderson grade II or IIIA fractures, as long as thorough debridement and adequate soft tissue coverage were performed. A similar conclusion can be obtained from the experience of treating other open injuries, especially intra-articular tibial fractures [
25‐
27]. Along with external fixation, limited internal fixation can offer sufficient stability and may decrease the incidence of subsequent reduction loss. The maintenance of the favourable reduction that is conducive to fracture healing can be inferred from the decreased number of union complications and the shorter time to full weight bearing and complete union. As a result, accelerated return to functional exercise and prompt return to normal work and life can be obtained.
However, some concerns are also proposed with this combined technique. First, without taking changing fixation into consideration, patients treated with the combined technique required additional surgical time and expenditure on average; this should be noticed when the patients are in poor health or poor economic condition. Moreover, although the internal implants were placed through the intrinsic wound or a necessary minor incision (rarely causing further disruption of the periosteum or compromise of the blood supply), additional disruption to surrounding soft tissues may occur.
In addition, there are some inherent limitations of external fixation. A high pin-track infection rate is the most common problem. The pin-site infection rate was as high as 44.8% in our study, but this did not result in an increased deep tissue infection risk. With our pin-site care protocol and detailed guidance in the discharge instructions, patients with pin-track infections received timely and successful treatment with oral antibiotics. Thus, we believe that this is a ‘local problem’ rather than an obstacle or a true complication. Moreover, the cumbersome nature of the external fixator is another drawback, leading to inconvenience in daily activities, and an additional procedure to change the fixation has a tendency to occur in some non-compliant patients. Therefore, we believe a mature discussion of the risks and benefits with patients is necessary; this may decrease the incidence of secondary operations to change the fixation system.
It should be noted that a novel Ni-Ti alloy (the ASC) was used for limited internal fixation in our study. In the past decade, ASCs have been increasingly used in the clinical treatment of various musculoskeletal diseases due to their excellent wear and corrosion resistance, good biocompatibility, and shape memory effect [
19‐
22]. According to our study, we believe that this connector is also a practical internal apparatus for treating open tibial shaft fractures. It can be used in conditions that are not suitable to be enhanced with cortical screws, including transverse fractures, fragments without the enough opposite cortex, and friable fragments under twisting force. Furthermore, this connector is much more flexible, which helps find the proper placement position for sufficient soft tissue coverage, as well as for procedures in narrow spaces, without additional damage to surrounding tissues. In addition, due to the inherent property of the shape memory alloy, the compression arms in the device provide sustained axial compression forces that can be transmitted across the fracture site to accelerate fracture healing [
19‐
22,
28].
There are several limitations to this study. The study was retrospective and non-randomized. Moreover, the sample size, while not small, was not large enough for more complex methods to control for confounding (subgroup analysis, multivariate analysis, etc.). Additionally, we did not routinely perform a functional score or life-quality score during follow-up, losing the relevant information in the treatment by the two therapies. To that end, the definition of union was not well-defined. In addition, it should be noted that the cost data were simply the direct costs of hospitalization. Finally, although this preliminary study revealed the feasibility of using ASCs in open tibial diaphyseal fractures, further biomechanical studies and analyses are needed.
Despite these limitations, our conclusions were strengthened by several study design characteristics. This was a retrospective cohort study comparing definitive external fixation using a conventional frame to external fixation plus limited internal fixation for open tibial shaft fractures. To minimize selection bias, as well as results bias, we excluded a portion of the patients (please refer to the exclusion criteria in the Patients and Methods section). Additionally, this study contained a reasonable sample size (n = 152) and provided a somewhat novel and effective approach in treating such fractures. Moreover, the study also achieved a minimum follow-up of more than 1 year.
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