With the increased morbidity of high-energy trauma, TSFs are common in long bone fractures, and most of them are high-energy injuries [1, 2]. The traditional view is that open anatomical reduction and internal fixation with plate and screw are commonly used methods for treating TSFs. Due to the special anatomical structure and limited coverage of soft tissue of the tibia, the incidence of postoperative complications such as skin infection, bone exposure, malunion, and nonunion is relatively high, which brings certain difficulties to the treatment [18, 19]. For the treatment of TSFs, an intramedullary nail is the gold standard, however, there are also complications such as poor rotational control due to oversized diameter of the medullary cavity, pain in the anterior knee area, and fat embolism. For TSFs with poor soft tissue conditions, there is a risk of intramedullary infection [18, 20]. External fixation technique, as a minimally invasive treatment method, is commonly used to treat open or poor soft tissue fractures [15, 21]. It belongs to minimally invasive elastic fixation and does not interfere with the blood flow inside and outside the medullary cavity of the fracture site [1, 8, 9, 22, 23]. The fixation strength is adjusted according to the fracture union process, which conforms to the Wolff's law of bone growth and is conducive to fracture union.
Satisfactory outcomes were achieved in the treatment of TSFs using either CHSF or ICEF [10, 11, 24–27]. But in terms of intraoperative procedures, surgeons prefer to use CHSF because of the short operation time and fewer C-arm radiograph times. For patients in CHSF group, by using the six quick universal adjustment rods, the fracture was manually closed for reduction, and the rods were then locked, achieving the goal of maintaining fracture stability. CHSF can make rapid fracture reduction and early damage control with no fixator alteration. For patients in ICEF group, after the intraoperative fracture reduction was completed, the postoperative fracture deformity probably needed to be adjusted, then the other components needed to be installed, which were relatively difficult to operate.
In our study, the most common complication of using an external fixator is pin tract infection. The total pin tract infection rate was 38% in CHSF and 35% in ICEF group, in accordance with reported data on pin tract infection rates [28]. All of these infections were treated by daily pin tract care and oral analgesics. As mentioned by Paley [17], we believe that such pin tract infections represent a "problem" rather than a true complication. Knee or ankle joint stiffness is also a common complication after external fixation technology for treating proximal or distal tibial fractures [28, 29]. Joint stiffness rates in CHSF and ICEF groups were similar (11% and 10%, respectively). This problem may be explained by the similar external fixation time in the two groups. To avoid affecting the functional exercise of the knee or ankle joint, all patients in this study did not use cross knee or ankle joint fixation for fractures. 2 patients experienced knee joint stiffness and 3 patients experienced ankle joint stiffness, which were relieved after guidance on knee or ankle joint exercise.
In CHSF group, 2 patients experienced fracture delayed union, which might be related to the slight movement of the six quick universal adjustment rods after locking, resulting in instability of the fracture site. After installing 2 threaded rods and compressing the fracture site, stability was improved and the fracture was ultimately healed. In addition, in ICEF group, there were 2 cases of fracture nonunion, which might be related to the destruction of the biomechanical microenvironment around the fracture site during repeated fracture reduction. By using autologous iliac bone grafting, the fractures finally healed. In this group, there was no delayed union of fracture, which might be related to using of push pull wires and arched wires to reduce shear and improve stability [30].
For patients in CHSF group, the initial reduction of tibial fracture was carried out. The operation time was short, the damage to the soft tissue around the fracture site was small, the surrounding biomechanical microenvironment was protected, and it was conducive to fracture union. The differences of mean translation and angulation in lateral view were statistically significant between the two groups despite all 46 patients achieving functional reduction. This might be resulted from the application of ICEF, as during manual reduction, the fracture line experienced instability, due to emphasizing only the AP radiograph and subjectively overlooking lateral radiograph. If the displacement of tibial fracture could not be restored to anatomical reduction during the surgery, it was more difficult to correct the residual deformity through threaded rods after the surgery. For CHSF group, it could achieve good fracture reduction by correcting deformities through computer software systems after the surgery. However, high operation cost and long learning curve may be limitations of CHSF.
The present study has several limitations. Firstly, this study is a retrospective comparative study, and there is randomness between the two groups, selection bias is inevitable. Second, the sample size of this study is small, and the number of included cases is limited, which may lead to deviations in statistical analysis outcomes. Therefore, it is necessary to expand the sample size to enrich this study, and even multi center studies to obtain more accurate conclusions. Nevertheless, this study directly compared the final clinical outcomes of CHSF and ICEF in the treatment of HETFs and preliminarily concluded.