Effects of Loading Conditions on the Pelvic Fracture Biomechanism and Discrimination of Forensic Injury Manners of Impact and Run-Over Using the Finite Element Pelvic Model

This study aimed to systematically simulate the responses of pelvic fracture under impact and run-over to clarify the effects of boundary and loading conditions on the pelvic fracture mechanism and provide complementary quantitative evidence for forensic practice. Based on the THUMS finite element model, we have validated the simulation performance of the model by a real postmortem human pelvis side impact experiment. A total of 54 simulations with two injury manners (impact and run-over), seven loading directions (0°, 30°, 60°, 90°, 270°, 300°, 330°), and six loading velocities (10, 20, 30, 40, 50, and 60 km/h) were conducted. Criteria of effective strain, Von-Mises stress, contact force, and self-designed normalized eccentricity were used to evaluate the biomechanism of pelvic fracture. Based on our simulation results, it’s challenging to distinguish impact from run-over only rely on certain characteristic fractures. Loads on the front and back were less likely to cause pelvic fractures. In the 30°, 60°, 300° load directions, the overall deformation caused a “diagonal” pelvic fracture. The higher is the velocity (kinetic energy), the more severe is the pelvic fracture. The contact force will predict the risk of fracture. In addition, our self-designed eccentricity will distinguish the injury manner of impact and run-over under the 90° loads. The “biomechanical fingerprints” based on logistic regression of all biomechanical variables have an AUC of 0.941 in discriminating the injury manners. Our study may provide simulation evidence and new methods for the forensic community to improve the forensic identification ability of injury manners.

Is It Beneficial to Optimize Vital Signs Before Embolization for Pelvic Fractures? A Dilemma Between Resuscitation and Hemostasis

Purpose Adequate resuscitation and definitive hemostasis are both important in the management of hemorrhage related to pelvic fracture. The goal of this study was to analyze the relationship between the amount of blood transfused before transcatheter arterial embolization (TAE) and the clinical outcome later in the disease course. Methods Patients with pelvic fractures who underwent TAE for hemostasis from January 2018 to December 2019 were studied. The characteristics of patients who received blood transfusions of >2 U (1000 mL) and ≤2 U before TAE were compared. The mortality rate, blood transfusion-related complications, and length of stay were compared between these two groups. Results Among the 75 studied patients, 39 (52.0%) received blood transfusions of ≤2 U before TAE, and the other 36 (48.0%) patients received blood transfusions of >2 U before TAE. The incidence rates of systemic inflammatory response syndrome, sepsis, and coagulopathy were significantly higher in the >2 U group (97.2% vs 81.1%, P = .027; 50.0% vs 27.0%, P = .045; and 44.4% vs 5.4%, P < .01, respectively). After nonsurvivors were excluded, the >2 U group had a significantly higher proportion (43.8% vs 14.7%, P < .001) of prolonged intensive care unit (ICU) length of stay (7 days or more) and a longer hospital length of stay (33.8 ± 15.1 vs 21.9 ± 94.0, P < .01) than the ≤2 U group. Pre-TAE blood transfusion >2 U serves as an independent risk factor for prolonged ICU length of stay and increased hospital length of stay. Conclusion Early hemostasis for pelvic fracture-related hemorrhage is suggested to prevent pre-TAE blood transfusion-associated adverse effects of blood transfusion.

Postoperative Reduction Quality May Be the Most Important Factor That Causes Worse Functional Outcomes in Open and Closed Pelvic Fractures

Background Data on the functional outcomes of patients with open pelvic fractures after osteosynthesis are limited, and whether open fracture is a risk factor for worse outcomes, as compared with closed fracture, remains unclear. This study aimed to compare the functional outcomes of patients with open and closed pelvic fractures and evaluate potential factors that might affect outcomes. Methods Overall, 19 consecutive patients with open pelvic fractures and 78 patients with closed pelvic fractures between January 2014 and June 2018 were retrospectively reviewed. All fractures were surgically treated, with a minimal follow-up period of three years. Patients’ demographic profile, associated injuries, management protocol, quality of reduction, and outcomes were recorded and analyzed. Results Patients with open pelvic fractures had higher new injury severity score, higher incidence of diverting colostomy, and longer length of stay. Both radiological and functional evaluations revealed no significant differences between the two groups at 1-year and 3-year evaluations. Multiple logistic regression analysis identified poor radiological outcomes (using Lefaivre criteria) and longer length of stay as risk factors for worse short-term functional outcomes. At 3-year evaluation, fair-to-poor radiological outcomes (using Matta/Tornetta and Lefaivre criteria) and the presence of diverting colostomy were potential risk factors. Conclusions Compared with closed pelvic fracture, open pelvic fracture was not an indicator of worse functional outcomes. Functional outcomes may be comparable between patients with open and closed pelvic fractures at different time points within three years postoperatively. Achieving anatomical reduction in a fracture is crucial, because it might affect patient satisfaction.

Rehabilitative management of pelvic fractures needs to be further optimized

We read with interest the review by Piccione et al. into the rehabilitative management of patients with pelvic fracture (PF). This review adds to our knowledge about the significance and indispensability of early multidisciplinary intervention in PF. From our perspective, however, potential bias might be caused by several unanswered questions. The uncertain methodological process and the unclear definition could misguide the rehabilitation strategies while still in dispute. Therefore, further high-quality studies should be conducted to optimize the multidisciplinary rehabilitation of patients with PF.