Precise measurement of microwave polarization using a Rydberg atom-based mixer.

A Rydberg atom-based mixer has opened up a new method to characterize microwave electric fields such as the precise measurement of their phase and strength. This study further demonstrates, theoretically and experimentally, a method to accurately measure the polarization of a microwave electric field based on a Rydberg atom-based mixer. The results show that the amplitude of the beat note changes with the polarization of the microwave electric field in a period of 180 degrees, and in the linear region a polarization resolution better than 0.5 degree can be easily obtained which reaches the best level by a Rydberg atomic sensor. More interestingly, the mixer-based measurements are immune to the polarization of the light field that forms the Rydberg EIT. This method considerably simplifies theoretical analysis and the experimental system required for measuring microwave polarization using Rydberg atoms and is of interest in microwave sensing.

Clinical Evaluation of Femoral Head Fractures: Which Classification Systems Have the Best Universality, Reliability, and Reproducibility?

BACKGROUND: Femoral head fractures are rare but potentially disabling injuries, and classifying them accurately and consistently can help surgeons make good choices about their treatment. However, there is no consensus as to which classification of these fractures is the most advantageous; parameters that might inform this choice include universality (the proportion of fractures that can be classified), as well as, of course, interobserver and intraobserver reproducibility. QUESTIONS/PURPOSES: (1) Which classification achieves the best universality (defined as the proportion of fractures that can be classified)? (2) Which classification delivers the highest intraobserver and interobserver reproducibility in the clinical CT assessment of femoral head fractures? (3) Based on the answers to those two questions, which classifications are the most applicable for clinical practice and research? METHODS: Between January 2011 and January 2023, 254 patients with femoral head fractures who had CT scans (CT is routine at our institution for patients who have experienced severe hip trauma) were potentially eligible for inclusion in this study, which was performed at a large Level I trauma center in China. Of those, 9% (23 patients) were excluded because of poor-quality CT images, unclosed physes, pathologic fractures, or acetabular dysplasia, leaving 91% (231 patients with 231 hips) for analysis here. Among those, 19% (45) were female. At the time of injury, the mean age was 40 ± 17 years. All fractures were independently classified by four observers according to the Pipkin, Brumback, AO/Orthopaedic Trauma Association (OTA), Chiron, and New classifications. Each observer repeated his classifications again 1 month later to allow us to ascertain intraobserver reliability. To evaluate the universality of classifications, we characterized the percentage of hips that could be classified using the definitions offered in each classification. The kappa (κ) value was calculated to determine interrater and intrarater agreement. We then compared the classifications based on the combination of universality and interobserver and intraobserver reproducibility to determine which classifications might be recommended for clinical and research use. RESULTS: The universalities of the classifications were 99% (228 of 231, Pipkin), 43% (99 of 231, Brumback), 94% (216 of 231, AO/OTA), 99% (228 of 231, Chiron), and 100% (231 of 231, New). The interrater agreement was judged as almost perfect (κ 0.81 [95% CI 0.78 to 0.84], Pipkin), moderate (κ 0.51 [95% CI 0.44 to 0.59], Brumback), fair (κ 0.28 [95% CI 0.18 to 0.38], AO/OTA), substantial (κ 0.79 [95% CI 0.76 to 0.82], Chiron), and substantial (κ 0.63 [95% CI 0.58 to 0.68], New). In addition, the intrarater agreement was judged as almost perfect (κ 0.89 [95% CI 0.83 to 0.96]), substantial (κ 0.72 [95% CI 0.69 to 0.75]), moderate (κ 0.51 [95% CI 0.43 to 0.58]), almost perfect (κ 0.87 [95% CI 0.82 to 0.91]), and substantial (κ 0.78 [95% CI 0.59 to 0.97]), respectively. Based on these findings, we determined that the Pipkin and Chiron classifications offer near-complete universality and sufficient interobserver and intraobserver reproducibility to recommend them for clinical and research use, but the other classifications (Brumback, AO/OTA, and New) do not. CONCLUSION: Based on our findings, clinicians and clinician-scientists can use either the Pipkin or Chiron classification systems to classify femoral head fractures based on CT images, with equal confidence. It seems unlikely that any new classifications will substantially outperform these, and the other available systems either lacked sufficient universality or reproducibility to recommend them for general use. LEVEL OF EVIDENCE: Level III, diagnostic study.

Deep Learning Assisted Diagnosis of Musculoskeletal Tumors Based on Contrast-Enhanced Magnetic Resonance Imaging.

BACKGROUND: Misdiagnosis of malignant musculoskeletal tumors may lead to the delay of intervention, resulting in amputation or death. PURPOSE: To improve the diagnostic efficacy of musculoskeletal tumors by developing deep learning (DL) models based on contrast-enhanced magnetic resonance imaging and to quantify the improvement in diagnostic performance obtained by using these models. STUDY TYPE: Retrospective. POPULATION: Three hundreds and four musculoskeletal tumors, including 212 malignant and 92 benign lesions, were randomized into the training (n = 180), validation (n = 62) and testing cohort (n = 62). FIELD STRENGTH/SEQUENCE: A 3 T/T1 -weighted (T1 -w), T2 -weighted (T2 -w), diffusion-weighted imaging (DWI), and contrast-enhanced T1-weighted (CET1 -w) images. ASSESSMENT: Three DL models based, respectively, on the sagittal, coronal, and axial MR images were constructed to predict the malignancy of tumors. Blinded to the prediction results, a group of specialists made independent initial diagnoses for each patient by reading all image sequences. One month after the initial diagnoses, the same group of doctors made another round of diagnoses knowing the malignancy of each tumor predicted by the three models. The reference standard was the pathological diagnosis of malignancy. STATISTICAL TESTS: Sensitivity, specificity, and accuracy (all with 95% confidential intervals [CI]) corresponding to each diagnostic test were computed. Chi-square tests were used to assess the differences in those parameters with and without DL models. A P value < 0.05 was considered statistically significant. RESULTS: The developed models significantly improved the diagnostic sensitivities of two oncologists by 0.15 (95% CI: 0.06-0.24) and 0.36 (95% CI: 0.24-0.28), one radiologist by 0.12 (95% CI: 0.04-0.20), and three of the four orthopedists, respectively, by 0.12 (95% CI: 0.04-0.20), 0.29 (95% CI: 0.18-0.40), and 0.23 (95% CI: 0.13-0.33), without impairing any of their diagnostic specificities (all P > 0.128). DATA CONCLUSION: The DL models developed can significantly improve the performance of doctors with different training and experience in diagnosing musculoskeletal tumors. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Cortical allograft strut augmented with platelet-rich plasma for the treatment of long bone non-union in lower limb- a pilot study.

BACKGROUND: The autogenous iliac bone graft is the first choice of surgical treatment for long bone non-union. However, many factors limit the use of autogenous bone, such as insufficient bone harvest and complications in the donor site. This study aimed to pilot-test the effectiveness of the cortical allograft strut augmented with Platelet-rich plasma (PRP) on long bone non-union in the lower limb. METHOD: This study was a one-armed pilot trial, with thirteen men and four women patients scheduled for surgery. Revision surgery for managing long bone non-union included debridement, internal fixation of the cortical allograft strut, and adding PRP in the fracture site. After surgery, outcome measurements of healing rate, healing time, the incidence of revision, and complications, were assessed at least one-year follow-up. RESULTS: Fourteen of seventeen participants completed all follow-ups. The mean age of 14 patients was 35.9 years (range, 18-56 years), and the mean BMI was 22.44 ± 1.53 kg/m2. All nonunions united after the operation. The mean healing time was 4.6 ± 0.7 months. There was no revision or complication. CONCLUSION: Cortical allograft strut augmented with PRP led to healing long bone non-union in the lower limb. More clinical research is required before widespread use.

Reoperation rate and implants' position variation features of displaced femoral neck fractures with sliding compression or length-stable fixation in young and middle-aged population.

INTRODUCTION: Sliding compression fixation and length-stable fixation are two basic internal fixation concepts in the treatment of displaced femoral neck fractures. In this study, we aimed to compare the reoperation rates for different methodologies of internal fixation for femoral neck fractures in young and middle-aged population. MATERIALS AND METHODS: This a retrospective study. A total of 215 patients with displaced femoral neck fractures treated with cannulated screw fixation were enrolled and divided into the sliding compression and length-stable groups according to the fixation pattern. The occurrence of and reason for revision surgery within one year were recorded. Forty-five patients with complete CT data (including CT scanning on the first postoperative day and at the last follow up) were selected from the total sample. A newly established computerized image processing method was used to evaluate variations in the spatial location of screws. RESULTS: The reoperation rate was significantly higher in the length-stable group (23.8%) than in the sliding compression group (7.3%). The rate of revision surgery due to nonunion was also higher in the length-stable group (11.4%) than in the sliding compression group (1.8%). However, no significant difference was observed in terms of joint penetration or soft tissue irritation. The sliding compression group (6.58 ± 3.18 mm) showed higher femoral neck shortening than length-stable group (4.16 ± 3.65 mm). When analyzing the spatial variations, a significantly greater screw withdrawal distance was observed in the sliding compression group than in the length-stable group, but with a smaller rotation angle. CONCLUSION: Length-stable internal fixation of displaced femoral neck fractures may lead to an increased reoperation rate in young and middle-aged population. TRIAL REGISTRATION: Name of the registry: Chinese Clinical Trial Registry. TRIAL REGISTRATION NUMBER: ChiCTR2000032327. Trial registration date: 2020-4-26.

Fracture line distribution in femoral head fractures: a complement to Pipkin, Brumback, and AO/OTA classifications.

PURPOSE: This study aimed to explore the fracture line distribution and validate fracture classifications of Femoral head fractures (FHFs). MATERIALS AND METHODS: A total of 209 FHFs were reviewed retrospectively. Subjects were classified by associated injuries and commonly used fracture classifications (Pipkin, Brumback, and AO/OTA), and the universality degree of classifications was evaluated. The fracture line directions were determined in the coronal and axial CT planes. 3D mapping analysis of fracture lines was performed separately by each group. 3D maps were employed to analyze the discrimination degree of inter-subtype classifications and create a new classification. The subjects were subsequently reclassified. Correlations between classifications were analyzed to determine the matching degree of the three classifications. RESULTS: The universality degrees were 98.6% (pipkin), 44.5% (Brumback), and 94.3% (AO/OTA). The cases of (100%) Brumback and (98.5%) AO/OTA can be classified by Pipkin. The mean angles of fracture lines to the coronal and axial axis of primary compressive trabeculae were 20.25° and 54.56°. The discrimination degrees of inter-subtype of classifications were 0 (Pipkin), 60% (Brumback), and 33% (AO/OTA). A new classification with three regions and five types was created on 3D maps. Pipkin and AO/OTA matched one region, while Brumback matched two regions. CONCLUSIONS: There were three distributed fracture regions in FHFs that mismatched Pipkin, Brumback, and AO/OTA classifications. The new classification, based on morphometric features of FHFs, could compensate for the shortcomings of commonly used classifications, improving their applicability in treating FHFs.

Frequency stabilization method for transition to a Rydberg state using Zeeman modulation.

We herein develop and demonstrate a stable frequency-locking scheme for Rydberg atomic experiments. We use the Zeeman effect to modulate the three-level ladder-type Rydberg electromagnetically induced transparency (EIT) signal to lock the laser frequency of the coupling light for transition from its intermediate state to a Rydberg state. The effects of polarization of the probe and coupling lights, and the amplitude of the AC modulated magnetic field ${{\boldsymbol B}_0}$B0 on the EIT and the corresponding dispersive error signal, are both analyzed. The results show that both the EIT signal and dispersive error signal are the strongest when the polarizations of coupling and probe fields are circular and equal. The signal-to-noise ratio of the dispersive error signal increases with ${{\boldsymbol B}_0}$B0. The slope of the dispersive error signal increases first and then decreases with ${{\boldsymbol B}_0}$B0, which is related to the increase of the EIT linewidth caused by the higher ${{\boldsymbol B}_0}$B0. The linewidth of the laser is significantly less than 500 kHz after frequency locking, which satisfies the requirements of most experiments involving Rydberg atoms. The method proposed herein can generally be applied to any cascade system of Rydberg atoms.

Dispersive microwave electrometry using Zeeman frequency modulation spectroscopy of electromagnetically induced transparency in Rydberg atoms.

We herein developed and demonstrated a Zeeman frequency modulation scheme for improving the signal-to-noise ratio of microwave electric field measurement using Rydberg atoms. The spectra of the electromagnetically induced transparency (EIT) and Autler-Townes splitting of Rydberg atoms is frequency modulated by an alternating current magnetic field. The signal-to-noise ratio of the corresponding dispersive error signal is enhanced more than 10 times than that of the original spectrum. Furthermore, we show that the slope of the dispersive error signal near the resonance of the Rydberg EIT can be used to characterize the weak microwave electric field amplitudes. The more intuitive and simpler structure compared with other existing frequency modulation technologies greatly reduces the difficulties of experiments and experimental data analysis.

The primary stability of different implants for intra-articular calcaneal fractures: an in vitro study.

BACKGROUND: Calcaneal fractures account for around 2% of all fractures and most of them are intra-articular fractures. Many implants have been used in the fixation of calcaneal fractures, but their biomechanical stability has not yet been well investigated. The aim of this study was to compare the primary stability of four fixations of calcaneal fracture. METHODS: Eight cadaveric calcaneus samples were used to simulate the Sanders' types III fracture pattern and fixed through four different implants, namely, K-wires, cannulated screws (CS), absorbable screws (AS), and plate-screw system (PSS). Each specimen was then placed into a custom-made jig and was loaded through a material testing machine to simulate the physiological condition. The primary stability was measured in the vertical direction as the stiffness and anterior-posterior direction as the calcaneocuboid force. One-way analysis of variance was used for data analysis. RESULTS: The results showed the highest stiffness of 634 (383-891; SD 226) N/mm in the intact model. It was significantly higher than the models fixed with K-wires, CS or PSS. There was no significant difference in vertical stiffness between fractures fixed with AS and the intact model or other fixed models. The intact model showed the lowest calcaneocuboid force of 153 (120-218; SD 39) N, while the fractures fixed with AS showed the greatest force of 242 (146-398; SD 84) N. The significance was only detected between these two models. CONCLUSIONS: The global stiffness was similar when the calcaneal fractures were fixed by K-wires, CS and PSS. The stability of the AS fixation differed along both the vertical and anterior-posterior directions, and was greatly influenced by the bone quality. AS for fracture fixation should be designed with greater strength and pull-out resistance.

The Protective Effect of Cordycepin On Alcohol-Induced Osteonecrosis of the Femoral Head.

BACKGROUND: Alcohol abuse is known to be a leading risk factor for atraumatic osteonecrosis of the femoral head (ONFH), in which the suppression of osteogenesis plays a critical role. Cordycepin benefits bone metabolism; however, there has been no study to determine its effect on osteonecrosis. METHODS: Human bone mesenchymal stem cells (hBMSCs) were identified by multi-lineage differentiation. Alkaline phosphatase (ALP) activity, RT-PCR, western blots, immunofluorescent assay and Alizarin red staining of BMSCs were evaluated. A rat model of alcohol-induced ONFH was established to investigate the protective role of cordycepin against ethanol. Hematoxylin & eosin (H&E) staining and micro-computerized tomography (micro-CT) were performed to observe ONFH. Apoptosis was assessed by TdT-mediated dUTP nick end labeling (TUNEL). Immunohistochemical staining was carried out to detect OCN and COL1. RESULTS: Ethanol significantly suppressed ALP activity, decreased gene expression of OCN and BMP2, lowered levels of RUNX2 protein, and reduced immunofluorescence staining of OCN and COL1 and calcium formation of hBMSCs. However, these inhibitory effects were attenuated by cordycepin co-treatment at concentrations of 1 and 10 µg/mL Moreover, it was revealed that the osteo-protective effect of cordycepin was associated with modulation of the Wnt/ß-catenin pathway. In vivo, by micro-CT, TUNEL and immunohistochemical staining of OCN and COL1, we found that cordycepin administration prevented alcohol-induced ONFH. CONCLUSION: Cordycepin treatment to enhance osteogenesis may be considered a potential therapeutic approach to prevent the development of alcohol-induced ONFH.

Reconstruction with double pedicel fibular graft and ankle arthrodesis for aggressive chondroblastoma in the distal tibia.

BACKGROUND: Aggressive chondroblastoma of the distal tibia is rare, and below-knee amputation had been the standard surgical procedure. CASE PRESENTATION: We reported an additional case and reviewed the existing literature. A 20-year-old man with a 2-month history of right ankle pain and swelling underwent distal tibia wide resection, double pedicle fibular, autogenous iliac bone graft, and ankle arthrodesis. He had no pain, no limitation in daily activities, and no evidence of local recurrence and infection; the Musculoskeletal Tumour Society Score (MSTS) is 86% at the final follow-up. CONCLUSIONS: Double pedicel fibular graft and ankle arthrodesis may be an effective and economical alternative method for aggressive chondroblastoma in the distal tibia.

Lactoferrin Inhibits IL-1ß-Induced Chondrocyte Apoptosis Through AKT1-Induced CREB1 Activation.

BACKGROUND/AIMS: Chondrocyte apoptosis is largely responsible for cartilage degeneration in osteoarthritis (OA). Interleukin-1 beta (IL-1ß) is widely used as a chondrocyte apoptosis-inducing agent, while lactoferrin (LF) is an anabolic reagent which has the potential to inhibit chondrocyte apoptosis. We assessed the effects of LF on cartilage degeneration in IL-1ß-induced chondrocytes and in a rat model of OA, and explored the potential molecular mechanisms involved. METHODS: Human articular chondrocytes (HACs) were treated with IL-1ß alone or in combination with LF. MTT and flow cytometric assays were used to detect changes after treatment with LF. Western blotting was used to examine the relevant molecules regulating apoptosis. RESULTS: We found that IL-1ß reduced the viability of HACs, whereas 200 µg/mL of LF significantly counteracted the inhibitory effect of IL-1ß. LF significantly inhibited IL-1ß-induced HAC apoptosis. The protein expression of the apoptotic markers Caspase-3 and PARP was also significantly reduced in the LF treatment group when analyzed by western blotting. Furthermore, we found that LF triggered CREB1 phosphorylation in IL-1ß-induced HAC apoptosis through AKT1 signaling. In addition, LF promoted the repair of articular cartilage damage in a rat OA model with elevated p-CREB levels. CONCLUSIONS: These studies suggest that LF has an anti-apoptotic effect on IL-1ß-induced chondrocytes, and thus may be a promising novel therapeutic agent for OA.

Femur performed better than tibia in autologous transplantation during hemipelvis reconstruction.

BACKGROUND: Pelvic reconstruction after hemipelvectomy can greatly improve the weight-bearing stability of the supporting skeleton and improve patients' quality of life. Although an autograft can be used to reconstruct pelvic defects, the most suitable choice of autograft, i.e., the use of either femur or tibia, has not been determined. We aimed to analyze the mechanical stresses of a pelvic ring reconstructed using femur or tibia after hemipelvectomy using finite element (FE) analysis. METHODS: FE models of normal and reconstructed pelvis were established based on computed tomography images, and the stress distributions were analyzed under physiological loading from 0 to 500 N in both intact and restored pelvic models using femur or tibia. RESULTS: The vertical displacement of the intact pelvis was less than that of reconstructed pelvis, but there was no significant difference between the two reconstructed models. In FE analysis, the stress distribution of the intact pelvic model was bilaterally symmetric and the maximum stresses were located at the sacroiliac joint, arcuate line, ischiatic ramus, and ischial tuberosity. The maximum stress in each part of the reconstructed pelvis greatly exceeded that of the intact model. The maximum von Mises stress of the femur was 13.9 MPa, and that of the tibia was 6.41 MPa. However, the stress distribution was different in the two types of reconstructed pelvises. The tibial reconstruction model induced concentrated stress on the tibia shaft making it more vulnerable to fracture. The maximum stress on the femur was concentrated on the connections between the femur and the screws. CONCLUSIONS: From a biomechanical point of view, the reconstruction of hemipelvic defects with femur is a better choice.

Functional outcomes and quality of life in patients with osteosarcoma treated with amputation versus limb-salvage surgery: a systematic review and meta-analysis.

INTRODUCTION: To perform a meta-analysis for comparing the functional outcomes and quality of life (QOL) of osteosarcoma patients receiving amputation or limb-salvage surgeries. MATERIALS AND METHODS: A search was conducted of the Medline, Cochrane, EMBASE, and Google Scholar on September 30, 2013. Studies were included in the analysis if there were patients who underwent amputation and limb-salvage surgery for osteosarcoma or Ewing's sarcoma, and for whom postoperative functional outcomes and QOL were evaluated. Outcomes were compared between participants who underwent limb-salvage operation and those who underwent amputation. The methodological quality of non-randomized comparative studies was assessed using the Newcastle-Ottawa Scale. RESULTS: A total of 121 studies were identified and 6 were included in the meta-analysis. Quality assessment indicated that all six studies were of high quality. The mean age of the participants ranged from 17 to 37 years, and among them 118 underwent amputations and 138 underwent limb-salvage procedures. The mean length of follow-up ranged from 28 to 145 months. The meta-analysis indicated that functional outcomes and QOL were similar between patients who underwent amputation and those who underwent a limb-salvage procedure. CONCLUSIONS: This meta-analysis including six high-quality studies indicates that amputation and limb-salvage surgery provide similar functional outcomes and quality of life for patients with osteosarcomas.

Osteocyte mitochondria regulate angiogenesis of transcortical vessels.

Transcortical vessels (TCVs) provide effective communication between bone marrow vascular system and external circulation. Although osteocytes are in close contact with them, it is not clear whether osteocytes regulate the homeostasis of TCVs. Here, we show that osteocytes maintain the normal network of TCVs by transferring mitochondria to the endothelial cells of TCV. Partial ablation of osteocytes causes TCV regression. Inhibition of mitochondrial transfer by conditional knockout of Rhot1 in osteocytes also leads to regression of the TCV network. By contrast, acquisition of osteocyte mitochondria by endothelial cells efficiently restores endothelial dysfunction. Administration of osteocyte mitochondria resultes in acceleration of the angiogenesis and healing of the cortical bone defect. Our results provide new insights into osteocyte-TCV interactions and inspire the potential application of mitochondrial therapy for bone-related diseases.

[Disastrous triad of femoral head:femoral neck fracture meeting fracture-dislocation of femoral head].

Femoral head and ipsilateral femoral neck fractures are serious and complicated injuries, which usually yield unsatisfactory results using conventional hip-preserving surgery. The key point of the management and prognosis mainly lies in femoral neck fractures. An apparent and consecutive relationship exists between femoral neck fractures and femoral head fracture-hip dislocation in such injuries. It is believed that disastrous triad of femoral head (DTFH) could summarize these specific injuries, and reflect the injury mechanism and prognostic characteristics. Based on our clinical observation and literature review, DTFH could be divided into three subgroups:TypeⅠ, common DTFH, in which femoral neck fractures occur following femoral head fractures-hip dislocation due to the same trauma; TypeⅡ, iatrogenic DTFH, in which femoral neck fractures come out in the caring process of femoral head fractures-hip dislocation; Type Ⅲ, stressed DTFH, in which femoral neck fractures occur after the management of femoral head fractures-hip dislocation. In the scenario, the line of femoral neck fractures locates distally to the femoral head fractures. Herein, we will discuss clinical characteristics of these types of DTFH.

Specific types of femoral head fractures: be alert for pre-, intra-, and post-operative ipsilateral femoral neck fractures following fracture-dislocation of the femoral head.

PURPOSE: Ipsilateral femoral head and neck fractures (iFHNFs) are rare types of fractures that confer extremely poor prognosis among femoral head fractures (FHFs). Owing to the rarity of FHFs, it is challenging to diagnose iFHNFs. In addition, the clinical features of iFHNF have not yet been comprehensively elucidated. Therefore, this retrospective study aimed to summarize and analyze the clinical characteristics of iFHNF using a clinical diagnostic simulation based on a prospectively maintained database. METHODS: Clinical data of consecutive patients with FHFs, including gender, age, injury side, and associated injuries, were collected and analyzed from a prospectively maintained orthopedic database at a large level-I trauma center for a clinical diagnostic simulation. Patients were stratified according to the presence or absence of iFHNF. Moreover, propensity score matching (PSM) was used to create 1:1 age- and gender-matched couples. Lastly, clinical factors were compared and identified between the two groups before and after matching. RESULTS: A total of 218 FHF patients were included. Fifteen patients were diagnosed with ipsilateral femoral neck fractures (iFNFs), including preoperative, intraoperative, and postoperative types. There were 177 male and 41 female patients, with a mean age of 40.0 ± 16.5 years. The incidence of two factors, namely acetabular fracture and posterior hip dislocation, were significantly different between the two groups (P < 0.05). Following PSM, 15 pairs of patients were generated. Comparisons revealed that the incidence of posterior hip dislocation was significantly different between the two groups (P < 0.05). CONCLUSIONS: There were three types of iFHNFs. In the context of FHFs, posterior hip dislocation was associated with iFNFs. Thus, surgeons should remain vigilant, not only intraoperatively but also postoperatively, for iFNFs following FHF and concomitant posterior hip dislocation. LEVEL OF EVIDENCE: Diagnostic level IV.

[Review of closed reduction techniques for femoral neck fracture].

For patients with femoral neck fractures who plan to undergo internal fixation, satisfied alignment of fracture ends is an important prerequisite for internal fixation stability and fracture healing. There are many reports on the reduction methods of displaced femoral neck fractures, which can be summarized into three categories:First, the solely longitudinal traction of lower limbs, supplemented by other manipulations such as rotation and compression; Second, the resultant force formed by the longitudinal traction of lower limbs and the lateral traction;the third is accomplished by vertical traction in the axis of femur with hip joint flexed. Each reduction method has its own advantages, but no single method can be applied to all fracture displacement. In this paper, some classical reduction techniques in the literatures are briefly reviewed. It is hoped that clinicians will not be limited to a certain reduction method, they should analyze the injury mechanism and fracture displacement process according to the morphology features and flexibly select targeted reduction methods to improve the success rate of closed reduction of femoral neck fracture.

Bone Grafting Can Promote the Prognosis of Displaced Femoral Neck Fractures: A Follow-up of the Clinical Significance of Bone Defects.

Background: Femoral neck fractures (FNFs) comprise a large proportion of osteoporotic fractures in Asia. However, the full range of prognostic variables that affect prognosis remains unclear. Here, we aimed to determine whether the severity of bone defects at the fracture site and other variables impact the prognosis of displaced FNFs. Methods: We evaluated the incidence of FNF internal fixation failures at regular intervals after surgery in data collected retrospectively. Digital Imaging and Communications in Medicine (DICOM) magnetic resonance imaging data of the displaced FNFs of 204 patients (> 20 years old; mean age, 52.3 years; men, 55.4%) who underwent internal fixation were used to construct three-dimensional (3D) virtual models of the femoral neck region. We calculated the position and volume of bone defect (VBD) using our independently developed algorithm and Mimics software. Each participant was followed up for at least 24 months; complications were noted and correlated with VBD and demographic and clinical variables. Results: On the basis of VBD values calculated from virtual reduction models, 57 patients were categorized as having a mild defect, 100 as having a moderate defect, and 47 as having a severe defect. Age (p = 0.046) and VBD (p < 0.001) were significantly correlated with internal fixation failure. Multivariate analysis revealed that severe bone defects were associated with internal fixation failure (adjusted odds ratio [aOR], 23.073; 95% confidence interval [CI], 2.791-190.732) and complications (aOR, 8.945; 95% CI, 1.829-43.749). In patients with a severe defect, bone grafting was inversely associated with internal fixation failure (aOR, 0.022; 95% CI, 0.002-0.268) and complications (aOR, 0.023; 95% CI, 0.002-0.299). Conclusions: Bone defect severity was associated with internal fixation failure and other complications. For young adults with large VBDs, bone grafting of the defect can reduce the risk of internal fixation failure. These results provide useful new quantitative information for precisely classifying displaced FNFs and guiding subsequent optimal treatments.

Fractured morphology of femoral head associated with subsequent femoral neck fracture: Injury analyses of 2D and 3D models of femoral head fractures with computed tomography.

Background: The injury of femoral head varies among femoral head fractures (FHFs). In addition, the injury degree of the femoral head is a significant predictor of femoral neck fracture (FNF) incidence in patients with FHFs. However, the exact measurement methods have yet been clearly defined based on injury models of FHFs. This study aimed to design a new measurement for the injury degree of the femoral head on 2D and 3D models with computed tomography (CT) images and investigate its association with FHFs with FNF. Methods: A consecutive series of 209 patients with FHFs was assessed regarding patient characteristics, CT images, and rate of FNF. New parameters for injury degree of femoral head, including percentage of maximum defect length (PMDL) in the 2D CT model and percentage of fracture area (PFA) in the 3D CT-reconstruction model, were respectively measured. Four 2D parameters included PMDLs in the coronal, cross-sectional and sagittal plane and average PMDL across all three planes. Reliability tests for all parameters were evaluated in 100 randomly selected patients. The PMDL with better reliability and areas under curves (AUCs) was finally defined as the 2D parameter. Factors associated with FNF were determined by binary logistic regression analysis. The sensitivity, specificity, likelihood ratios, and positive and negative predictive values for different cut-off values of the 2D and 3D parameters were employed to test the diagnostic accuracy for FNF prediction. Results: Intra- and inter-class coefficients for all parameters were ≥0.887. AUCs of all parameters ranged from 0.719 to 0.929 (p < 0.05). The average PMDL across all three planes was defined as the 2D parameter. The results of logistic regression analysis showed that average PMDL across all three planes and PFA were the significant predictors of FNF (p < 0.05). The cutoff values of the average PMDL across all three planes and PFA were 91.65% and 29.68%. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, predictive positive value and negative predictive value of 2D (3D) parameters were 91.7% (83.3%), 93.4% (58.4%), 13.8 (2.0), 0.09 (0.29), 45.83% (10.87%), and 99.46% (98.29%). Conclusion: The new measurement on 2D and 3D injury models with CT has been established to assess the fracture risk of femoral neck in patients with FHFs in the clinic practice. 2D and 3D parameters in FHFs were a feasible adjunctive diagnostic tool in identifying FNFs. In addition, this finding might also provide a theoretic basis for the investigation of the convenient digital-model in complex injury analysis.