Treatment of Pauwels type III femoral neck fracture with medial femoral neck support screw: a biomechanical and clinical study

Association between surgical delays for femoral neck fractures and early postoperative complications in young and middle-aged adults: A study based on the national inpatient sample database

BACKGROUND

Femoral neck fractures (FNF) in young and middle-aged adults are primarily caused by high-energy injuries in traffic accidents. Surgical delays often occur due to transportation issues, preoperative evaluations, and economic burdens.

METHODS

A retrospective analysis was conducted on young and middle-aged FNF patients undergoing reduction and internal fixation surgeries from 2010 to 2019 with the use of the National Inpatient Sample database. Logistic regression analysis was used to assess the relationship between surgical delays and complications, and the independent risk factors contributing to delays. Categorical variables were investigated via a chi-square test, while continuous variables including Elixhauser Comorbidity Index (ECI) scores, length of hospital stay (LOS), and total medical costs were analyzed via t-test or rank-sum test.

RESULTS

9,204 patients undergoing reduction and internal fixation surgeries were included. In the delayed group, patients had higher ECI scores, longer hospital stays, higher expenses, and increased inpatient mortality (1.61% vs. 0.28 %, P < 0.0001). Longer surgical delays were associated with higher risks of complications, including femoral head osteonecrosis, internal fixation loosening and breakage, and respiratory complications. Fluid and electrolyte disorders, metastatic cancer, pulmonary circulation disorders, and renal failure were identified as independent risk factors for surgical delays. Except for anemia (OR=2.37, P < 0.0001), no significant differences in early postoperative complications were found between open-reduction and closed-reduction internal fixation (ORIF/CRIF) surgeries.

CONCLUSION

Early surgical intervention, within a 2-days period after injury, seems to be crucial for young adults with FNF. If CRIF is challenging in some cases, ORIF can be another choice.

Biomechanical Study of Three Cannulated Screws Configurations for Femur Neck Fracture: A Finite Element Analysis

Background

To improve the performance of cannulated screws (CSs) in the treatment of femoral neck fractures (FNF), a number of new screw configurations have been proposed. However, most of the studies have only analyzed the biomechanical performance of different screw configurations under static conditions. This study aimed to investigate the biomechanical performance of three cannulated screws configurations under different loadings through finite element analysis.

Methods

In this FEA study, nine numerical models of proximal femur were employed to analyze the mechanical response of various fracture types and different fixation strategies (three inverted triangular parallel cannulated screws (TCS), four non-parallel cannulated screws (FCS) and biplane double-supported screw fixation (BDSF) respectively). The maximum principal strain (MPS) on the proximal femur and the von Mises stress on the screws were compared for different models.

Results

In Pauwels I and II fractures, FCS had the lowest peak MPS on the proximal femur and the BDSF had highest peak MPS value. In Pauwels III fractures, BDSF performance in MPS is improved and better than FCS under partial loading conditions. FCS exhibits the lowest von Mises stress in all load conditions for all fracture types, demonstrating minimal risk of screws breakage.

Conclusions

FCS is an ideal screw configuration for the treatment of FNF. And BDSF has shown potential in the treatment of Pauwels type III FNF.

Evaluation of the clinical efficacy of using an inverted triangular cannulated compression screw in combination with positive or negative buttress reduction for the healing of femoral neck fractures

OBJECTIVE

We aimed to compare the clinical efficacy of inverted triangular cannulated compression screws combined with Gotfried positive or negative buttress reduction in the healing of femoral neck fractures.

METHODS

Between October 2017 and March 2021, 55 patients with femoral neck fractures underwent treatment using inverted triangular cannulated compression screws combined with Gotfried positive or negative buttress reduction. Among these patients, 29 received inverted triangular cannulated compression screws combined with Gotfried positive buttress reduction treatment. This group consisted of 16 males and 13 females, with an average age of 43.45 ± 8.23 years. Additionally, 26 patients received inverted triangular cannulated compression nails combined with Gotfried negative buttress reduction treatment. This group included 14 males and 12 females, with an average age of 41.96 ± 8.69 years. Postsurgery, various measurements were taken, including the degree of shortening of the femoral neck, degree of bone nonunion, degree of fixation failure, degree of ischemic necrosis of the femoral head, and Harris score of the hip joint.

RESULTS

All patients were followed up for a minimum of 18 months. The group that underwent treatment with an inverted triangular cannulated compression screw combined with Gotfried positive buttress reduction did not experience any cases of bone nonunion, fixation failure, or ischemic necrosis of the femoral head. In the group that received treatment with inverted triangle cannulated compression screws combined with Gotfried negative buttress reduction, there was one case of bone nonunion, three cases of early fixation failure, and one case of ischemic necrosis. Ultimately, five patients (19.23% of the total) underwent joint replacement surgery. The average shortening lengths in the vertical plane were 4.07 ± 1.98 mm and 8.08 ± 3.54 mm, respectively. In the horizontal plane, the average shortening lengths were 3.90 ± 1.57 mm and 7.77 ± 3.31 mm, respectively. At the last follow-up, the group that received Gotfried positive buttress reduction had a greater Harris hip joint score.

CONCLUSION

The success rate of combining inverted triangular cannulated compression screws with Gotfried positive buttress reduction surgery is relatively high. This surgical approach effectively prevents femoral neck shortening and improves hip joint function. Moreover, it is crucial to avoid negative buttress reduction when managing femoral neck fractures.

Evaluation of full thread screw and different fixation configurations in Pauwels type III femoral neck fracture

Objectives

The purpose of this study is to evaluate the value of full thread screw and different fixation configurations in Pauwels type III femoral neck fracture.

Methods

A total of 40 artificial femoral model specimens were chosen, and Pauwels type III femoral neck fracture was simulated upon osteotomy at 80°. According to random number table, models were divided into four groups (10 cases in each group): Group A received the paralleled fixation with three partial thread screws (PTSs), group B received the crossed fixation with three PTSs, group C received the paralleled fixation with two full thread screws (FTSs) and one PTS, and group D received the crossed fixation with two FTSs and one PTS. Changes including the model rigidity, axial displacement in fatigue test and limit loads for Pauwels type III femoral neck fracture models were analyzed through MTS 858 Mini Bionix Ⅱ test system.

Results

Among four groups, the model rigidity, axial displacement in fatigue test and limit loads were the highest in group D, and they were the lowest in group A. However, the model rigidity, axial displacement in fatigue test and limit loads between group B and group C showed no statistically significant difference (P＞0.05). Eventually, all the specimens were displaced along the fracture lines while the femoral head was split at varying degrees. After splits, the removal rate of fixation screws in group A (60.0 %) and group C (40.0 %) was significantly higher than that of group B (10.0 %) and group D (0 %) (P＜0.05), but it showed no statistically significant difference between group A and group C, and between group B and group D (P＞0.05).

Conclusions

The crossed fixation configuration with two FTSs and one PTS in group D is proven to be more effective, which can go against the shear stress, tension and introversion in Pauwels type III femoral neck fracture models.

Femoral neck system and cannulated compression screws in the treatment of non-anatomical reduction Pauwels type-III femoral neck fractures: A finite element analysis

BACKGROUND

High shear force is a major factor detrimental to the healing of vertical femoral neck fractures. In addition to firm fixation, reduction quality is crucial for postoperative stability. The present study aimed to compare the biomechanical stability of the newly invented femoral neck system and three inverted-triangle cannulated compression screws treatments for non-anatomical reduction of Pauwels type-III femoral neck fractures.

METHODS

A total of 18 non-anatomical reduction Pauwels type-III femoral neck fracture finite element models were fabricated and fixed using three inverted-triangle cannulated compression screws or the femoral neck system. A 1950-N force was applied to the femoral head to simulate the physiological load during a single-leg stance. Parameters of the maximum total deformation, the interfragmentary gap, and the maximum von Mises stress of the implants and the proximal femur were analyzed.

FINDINGS

The results of the maximum total deformation, interfragmentary gap, and maximum von Mises stress of the implants in the negative-negative buttress model fixed by the femoral neck system were the largest among all groups (3.58 mm, 0.252 mm, and 729.68 MPa, respectively). In contrast, the anatomical-anatomical reduction model fixed by three inverted-triangle cannulated compression screws demonstrated the minimum total deformation, interfragmentary gap, and minimum von Mises stress of implants (1.107 mm, 0.09 mm, and 189.83 MPa, respectively).

INTERPRETATION

Anatomical reduction or positive buttress in femoral neck fractures should be recommended during fracture reduction. The femoral neck system showed weaker biomechanical stability than three inverted-triangle cannulated compression screws in treating Pauwels type-III femoral neck fractures.

Research hotspots and trends in internal fixation of femoral neck fractures from 2010 to 2022: A 12-year bibliometric analysis

BACKGROUND

This study endeavors to scrutinize the hotspots and trends in the literature concerning the internal fixation of femoral neck fractures (INFNF) through a comprehensive bibliometric analysis. Notably, this analytical process encompasses both qualitative and quantitative components.

METHODS

The present study has utilized the Science Citation Index-Expanded from the Web of Science Core Collection to extract datasets ranging from January 1, 2010, to August 31, 2022. Quantitative analysis was carried out using sophisticated analytical tools such as the Bibliographic Item Co-Occurrence Matrix Builder, the Online Analysis Platform of Literature Metrology, and CiteSpace software. Further, the major Medical Subject Headings terms and their subheading counterparts associated with INFNF were extracted from the PubMed2XL website using the corresponding PMIDs. These Medical Subject Headings terms were employed in conducting a co-word clustering analysis. Ultimately, the Graphical CLUstering TOolkit program was utilized to execute a co-word biclustering analysis to discern the prevailing hotspots in this domain.

RESULTS

Between January 1, 2010, and August 31, 2022, a total of 463 publications were issued on INFNF. The INJURY-INTERNAL JOURNAL OF THE CARE OF THE INJURED stood out as the most extensively perused journal in this area. Notably, China emerged as the foremost contributor to publishing articles within the last 12 years, followed by the United States and Canada. McMaster University was identified as the leading institution in INFNF research, while Bhandari M emerged as the most prolific author in this field. Moreover, the study identified five notable research hotspots within the domain of INFNF.

CONCLUSIONS

This study has identified five critical areas of research in the field of INFNF. It suggests that the primary focus of future research is likely to center on advancing internal fixation methods and robot-assisted instrumentation for femoral neck fractures. As such, this study provides valuable insights into future research directions and ideas for those working in this field.

Novel screw fixation placement configuration for the treatment of Pauwels type III femoral neck fractures: a finite element analysis

Verticality of transcervical hip fractures in young patients is usually connected with typically high-energy fractures which are known as Pauwels type III. Artificial femoral head replacement surgery is mostly not considered for treating femoral neck fractures in such patients. The commonly used devices for the fixation of vertical femoral neck fractures are multiple screws or a sliding hip screw with or without an antirotation screw. Size, location and length of the screws are the most effective parameters in terms of the structural performance of internal fixation implants, but the optimal configuration of the screws is necessary to be investigated to direct the clinical practice. The aim of this study is to compare the biomechanical stability of the standard inverted triangle configuration with the various newly proposed x-crossed screw configurations. FEA simulations carried out in this study demonstrated that using an x-crossed-right assembly in treating Pauwels type III femoral neck fractures satisfies the biomechanical stability in terms of maximum von Mises stresses and maximum femoral head displacement. However, in terms of maximum relative neck fracture displacement, the x-crossed-right assembly would not entirely suffice the desired biomechanical stability. Therefore, using an x-crossed screw assembly in treating femoral neck fractures would provide the needed biomechanical stability.