Locking plate versus circular external fixator as a definitive external fixator in the treatment of open distal tibia fractures: a retrospective study
Authors: chen wei , chen zhangxin , zhang cong , wang mengyuan , xu wenbin , gao mingming , ding zhenqi 
Published: February 2022

Abstract
Background: Local soft tissue contusion, bone exposure, and wound contamination are often accompanied by open distal tibia fractures. External fixation is the most commonly used temporary or terminal fixation treatment. The locking plate as external stent fixation and circular external fixator has become the major technical surgery for the definitive treatment of open distal tibia fractures. Both can achieve reliable fixation of fracture ends that do not cross the ankle joint and promote fracture healing and soft tissue repair. This study aimed to compare the functional and radiological outcomes of external locking plate and circular external fixator in the treatment of open distal tibia fractures.Methods: Emergency operation patients treated for open distal fractures in ⅓ segment of the tibia (all were extra-articular fractures) between October 2016 and October 2020 were retrospectively investigated. Patients were divided by a random number table into a locking plate external fixation treatment group (External Locking Plate group, group Ⅰ) and a circular external fixation frame treatment group (Circular External Fixator group， group Ⅱ). A total of 77 patients (34 females and 41 males) with a mean age of 31.60±10.92 (range: 18-60) years were evaluated. Fractures were graded according to Gustilo and AO/ASIF classification, respectively. In the External Locking Plate group (31 cases), Gustilo type II 18 and Gustilo type IIIA 13. Then according to the AO/ASIF classification, 14 by type 42-B, 14 by 42-C, and 3 by 43-A; While in the Circular External Fixator group (46 patients), there were Gustilo type II (23 patients) and Gustilo type IIIA (23 patients), type 42-B (25 patients), type 42-C (17 patients), and type 43-A (4 patients). The general data such as gender, age, and cause of injury were recorded and compared between the two groups. The clinical and radiographic outcomes were retrospectively evaluated, such as the surgical time, the surgical surface notch of the external fixative object, postoperative wound infection rate, incision infection rates, bone healing time, nonunion rate, secondary surgery rate, the number of angulation degrees in the fracture area at the last X-ray, and the Johner-Wruhs functional score of the ankle at the last follow-up.Results: All patients were followed up for a mean period of 13.71 ± 2.61 months (range 9-18 months). The operative time was 66.90 ± 5.37) minutes and 84.74 ± 6.72) minutes in the External Locking Plate group and Circular External Fixator group, respectively. The patients had an external fixation object surface notch of (2.00 ± 0.21) cm and (5.30 ± 1.10) cm, respectively. In incision infection rates, eight nail infections in the External Locking Plate group (8 / 228) and 28 nail infections (28 / 365) were diagnosed in the Circular External Fixator group. For the Johner-Wruhs functional score of the ankle at the last follow-up, 26 superior and 4 superior and 1 inferior in the External Locking Plate group; 96.7% (30 / 31) superior and 24 superior and 17 inferior and 5 inferior in the Circular External Fixator group; 89.1% (41 / 46) superior and 3.67 ± 1.38 (1.8-5.4) degrees in the Circular External Fixator group at the last X-ray fracture zone compared with 6.04 ± 2.13 (3.6-9.2) degrees in the External Locking Plate group. The degree of deformity angulation was small. All of the above indexes showed statistically significant differences between the two groups. There were no significant differences between the two groups in bone healing time, nonunion rate, secondary surgery rate, and postoperative wound infection rate. In the External Locking Plate group, three patients required adjustment of plate height or position at the time of secondary surgery, and one patient was changed to a combined external fixator; while in the Circular External Fixator group and 2 patients had nonunion, all of whom underwent two-stage bone grafting, and 3 had deep wound infection and two-stage augmentation procedures in which one to two fixation pins were adjusted for each intraoperative period and then healed via skin flap and bone grafting.Conclusion: Both the External Locking Plate group and the Circular External Fixator group effectively promoted bone and soft tissue repair as the terminal treatment for open fractures of the distal tibia. The former group has some advantages such as simple operation, low notch, low pin eye infection rate, and more excellent preservation of ankle function, but there is a residual deformity or anterior tibial soft tissue necrosis after surgery, infection requiring secondary expansion, and flap repair when surgery is performed, greater adjustability, and operational adaptability of the annular outer shelf.