Pelvic and acetabular fractures are one of the serious traumatic diseases, leading to a high rate of disability and fatality. Their operative principles are anatomical repositioning and rigid fixation to achieve early functional exercise and avoid complications. The updating modern technology has made precision and minimally invasion a trend in orthopedic surgery. An increasingly number of new technologies has been applied in clinical surgery, such as three-dimensional printing, three-dimensional navigation, and orthopedic robotics, each with its own characteristics. Of them, three-dimensional printing technology is more advantageous in terms of reducing surgical cost and risk, enhancing surgical efficiency, achieving surgical precision and reducing radiation exposure, as evidenced by a large number of clinical case reports and randomized controlled trials. This paper summarizes the current situation and assesses the prospects of three-dimensional printing technology in the diagnosis and treatment of pelvic and acetabular fractures in order to provide reference for orthopedic colleagues.

Objective:To compare the parameters for infra-acetabular screw placement between men and women using a digital Chinese anatomical model of the pelvis and acetabulum.Methods:The normal pelvic CT data were collected from the 163 adult patients who had been admitted to the Traditional Chinese Medicine Hospital of Xinjiang Uygur Autonomous Region from January 2018 to December 2021. There were 61 males and 102 females with an age of 53.0 (45.0, 60.0) years. Mimics 21.0 software was used to reconstruct the three dimensional pelvis which was then imported into Autodesk maya 2022 software before the model was flattened. Polygonal modeling tools were used to create a cylinder to simulate an infra-acetabular screw for length and angle measurements of the screw. The diameters of the infra-acetabular screws were measured by axial fluoroscopy in Mimics 21.0 software. The maximum diameters and maximum lengths of the infra-acetabular bone channel were compared between males and females, and the angles between the axis of the infra-acetabular screw and the anterior pelvic plane and the median sagittal plane were also compared between genders.Results:The maximum diameters of the left and right infra-acetabular corridors were 5.24 (4.26, 6.38) mm and 5.04 (4.50, 6.57) mm in males, and 3.99 (3.81, 4.51) mm and 3.89 (3.65, 4.90) mm in females; the maximum lengths of the left and right infra-acetabular corridors were (98.43±4.42) mm and (98.01±5.08) mm in males and 87.73 (84.22, 90.98) mm and 87.51 (84.59, 90.15) mm in females. The left and right angles between the infra-acetabular screw axis and the median sagittal plane were -0.98°±4.79° and -1.08°±4.91° in men, and 6.20° (3.34°, 11.16°) and 6.44° (3.77°, 11.85°) in women. The differences in the above data between men and women were statistically significant ( P<0.05). There was no statistically significant difference between men and women in the angle between the infra-acetabular screw axis and the anterior pelvic plane ( P>0.05). Conclusions:The length and diameter of the infra-acetabular corridor in males are greater than those in females, the angle between the infra-acetabular corridor and the sagittal plane in males is smaller than that in females, and the infra-acetabular corridor in males is more parallel to the sagittal plane. Therefore, the fluoroscopy angle should be adjusted for males to reduce the difficulty in screw placement when an infra-acetabular screw is placed during surgery.

The principles for surgical treatment of femoral neck fracture are anatomical reduction, rigid fixation and reduction of iatrogenic tissue damage to maintain sufficient blood supply and reduce the risk of complications such as avascular necrosis of the femoral head. In the evolution of internal fixation structures for femoral neck fracture, a variety of new products have been developed, such as the neck-shaft angle stabilization structure represented by dynamic hip screw, the multi-screw structure represented by three cannulated screws, and the plate-screw structure represented by multi-screw structure combined with a locked plate. These internal fixation structures have their own advantages and disadvantages in terms of stability and reduced risk of complications. However, none of them can perfectly meet the requirements of all the surgical principles. Femoral neck system (FNS) was firstly applied in clinic practice in 2017 to further improve the internal fixation of femoral neck fracture. In recent years, its mechanical properties and clinical effects have been widely reported in an attempt to further improve the implantation of this internal fixation device. This article reviews the researches on the mechanical properties and clinical efficacy of FNS and the suggestions put forward by orthopedic surgeons to improve the implantation methods of FNS.