Clinical efficacy and biomechanical analysis of robotic internal fixation with percutaneous screws in the treatment of both-column acetabular fractures

Abstract

Both-column fractures of the acetabulum represent a particularly complex category of injury, with a high proportion necessitating surgical intervention. The most common surgical method is open reduction and internal fixation (ORIF), but this has problems like blood loss, long operations, and trauma after surgery. Robot-assisted percutaneous screw fixation is a minimally invasive treatment for both-column acetabular fractures. It has several clinical advantages, including precise screw positioning and stable performance. A comparison of the clinical efficacy of open reduction and internal fixation and robot-assisted percutaneous screws in the treatment of both-column acetabular fractures and biomechanical analyses were performed to compare the stability of the two fixation methods. Firstly, A finite element model was constructed for the purposes of analyzing both-column acetabular fractures, percutaneous screws, and reconstruction plates. Divided into four experimental groups: Group I: Acetabular anterior and posterior columns are screwed with a 6.5 mm percutaneous screw. Group II: The anterior column of the acetabulum is fixed with a 6.5 mm percutaneous screw, while the posterior column is fixed with a 7.3 mm percutaneous screw. Group III: Acetabular anterior and posterior columns are screwed with a 7.3 mm percutaneous screw. Group IV: Acetabular anterior and posterior columns are fixed with a 6-hole reconstruction plate. Each fracture group was tested under axial loads of 600 N to measure the hipbone's displacement, Von Mises stress (VMS), and its internal fixation components. Secondly, 36 patients with both-column acetabular fractures admitted from September 2020 to September 2023 were retrospectively analyzed; 19 of them in the ORIF group, and 17 of them in the robot-assisted group. A comparison of the operative time, duration of intraoperative fluoroscopy, intraoperative blood loss, incision length, Matta's radiological criteria, and Harris Hip Score (HHS) in two groups of patients. In terms of finite element analysis, the maximum VMS was observed for internal fixation in group II, and the minimum VMS was observed in group IV. The displacements of groups I, II, and III internal fixation were the same (approximately 1.00 mm), and the minimum internal fixation displacement was observed in group IV. The mean operating time in the ORIF group was 190.45 ± 25.40 min, the incision length was 20.56 ± 3.38 centimeters, the intraoperative bleeding was 958.73 ± 128.68 ml, and the fluoroscopy time was 55.18 ± 10.25 s. The mean operating time in the robotic group was 99.7 ± 18.8 min, with an incision length of 7.35 ± 0.56 cm, intraoperative bleeding of 50.00 ± 15.20 ml, and fluoroscopy time of 22.52 ± 14.50 s. There was a significant difference between the above data (P < 0.001). There was no significant difference in Matta's radiological criteria between the two groups. HHS at three months postoperatively and six months postoperatively were 77.81 ± 2.23 and 84.78 ± 4.65 in the ORIF group, and at three months postoperatively and six months postoperatively in the robotic group were 72.19 ± 1.85 and 82.28 ± 3.32. The use of robot-assisted percutaneous screw internal fixation for both-column acetabular fractures has been demonstrated to have similar fixed strength and therapeutic effect to that of ORIF plate fixation. In contrast, robot-assisted percutaneous screw therapy offers the advantages of minimal invasiveness and precision, thereby providing a novel therapeutic option for the clinical treatment of both-column acetabular fractures.

Keywords: Both-column acetabular fractures; Finite element analysis; Percutaneous screw.; Robot.

Fig. 1

TiRobot system.

Fig. 2

The images presented here are those of a female patient obtained through the use of a fracture imaging technique. A-C: 3D representation of the patient’s fracture. D-I: CT image of the patient’s fracture.

Fig. 3

Auxiliary operation process of the TiRobot orthopedic robot. A Intra-operative CT imaging. B Navigator positioning. C-D The simulation of screw placement. E The effect of anterior column screw fixation. F The effect of posterior column screw fixation. G The effect of both-column acetabular fractures screw fixation. H: Images of the pelvic region obtained at the bedside following surgery.

Fig. 4

Post-operative follow-up images of the patient above. A-B: Images of the patient three months after surgery. C-D: Images of the patient six months after surgery.

Fig. 5

Preoperative and postoperative follow-up imaging images of a 24-year-old female patient treated with ORIF. A-C Imaging pictures of the patient’s preoperative fracture. D-F Images of the patient three months after surgery. G-I Images of the patient six months after surgery.

Fig. 6

Model of 4 internal fixation modalities. A Group I: both the anterior and posterior columns were fixated with 6.5 mm percutaneous screws. B Group II: a 6.5 mm percutaneous screw in the anterior column and a 7.3 mm percutaneous screw in the posterior column. C Group III: both the anterior and posterior columns were fixated with 7.3 mm percutaneous screws. D Group IV: Acetabular bicolumn fixation using reconstruction plates.

Fig. 7

VMS of the hip bone and internal fixation. A-B were representative of the group I. C-D were representative of the group II. E-F were representative of the group III. G-H were representative of the group IV. The red areas in the hip and internal fixation experienced the maximum VMS, whereas the blue area experienced the minimum VMS.

Fig. 8

Displacement of the hip bone and internal fixation. A-B were representative of the group I. C-D were representative of the group II. E-F were representative of the group III. G-H were representative of the group IV. The red areas in the hip and internal fixation experienced the maximum deformation, whereas the blue area experienced the minimum deformation.

Fig. 9

Finite element results for hip bones and internal fixation. A Displacement at the hip fracture site. B Displacement of internal fixation. C VMS at the hip fracture. D VMS with internal fixation.