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.

Biomechanical study of a new rim plate fixation strategy for two kinds of posterolateral depression patterns of tibial plateau fractures: a finite element analysis

PURPOSE

The biomechanical capacity of "Barrel Hoop Plate (BHP)" in the treatment of the posterolateral tibial plateau (PL) depression fractures remains unknown. In this study, two kinds of posterolateral tibial plateau depression models involving mild slope-type depression fracture (MSDF) and local sink hole-type depression fracture (LSDF) were created to test and compare the biomechanical capacities of BHP with the other two conventional fixations (Anterolateral Plate and Posterolateral Plate, ALP and PLP) by finite element analysis.

METHODS

The 3D models of three kinds of plate-screw systems and the two kinds of PL-depression models (MSDF and LSDF) were created. An axial force of 400N was applied from the distal femur to the tibial plateau. The maximal displacements of the posterolateral fractures (PLFs), the distribution on the PLFs articular surface and key points displacements were measured. Stresses in the fixation complex including the maximal Equivalent (von-Mises) Stress of implants, the max shear stress of PLFs and stiffness of the fixation were calculated.

RESULTS

The maximal displacement of MSDF was least in Group BHP. The maximal displacement of LSDF was least in Group ALP. In MSDF, BHP showed the best rim fix effect in MSDF, but unsatisfactory results in LSDF. In both MSDF and LSDF, the greatest max Equivalent Stress of the plate and the screw occurred in the PLP system. ALP and BHP showed a comparable stiffness in MSDF and ALP had the strongest stiffness in the fixation of LSDF.

CONCLUSIONS

In MSDF, the BHP has the best biomechanical capacity, especially in displacements of key points such as the PL rim, fracture line, and depression center. In LSDF, the ALP system shows the best biomechanical effect. Although the PLP has the best fixation effect on the posterior wall, it is not suitable for PL-depression fracture fixation.

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.

Relative efficacy of three different tendon repairs in complete flexor digitorum profundus laceration in Zone I: A randomized controlled study

Hand flexor tendon injuries are common and biomechanically challenging to achieve good functional outcomes. Several approaches using the Pennington-modified Kessler repair technique have been attempted, but high-level evidence is still lacking. Here, we evaluated the relative efficacy of three versions of the Pennington-modified Kessler technique in repairing complete flexor digitorum profundus (FDP) laceration in Zone 1. We conducted a 2-year, single-center, double-blind, randomized clinical trial involving 85 patients with 105 digits enrolled between June 1, 2017 and January 1, 2019. Eligible participants were 20-60 years of age and underwent tendon repair in the acute phase for complete FDP laceration distal to the insertion of the superficial flexor tendon. The digits were randomized 1:1:1 to three treatment groups: (1) Pennington-modified Kessler repair; (2) Pennington-modified Kessler repair followed by circumferential tendon suture; or (3) Pennington-modified Kessler repair followed by circumferential epitenon suture. The primary endpoint was total active range of motion (TAROM) at 2 years after the initial surgery. The secondary endpoint was the reoperation rate. Compared with group 1, both techniques for peripheral suture were associated with a decrease in TAROM at 2 years after surgery. The total reoperation rates of the three groups were 11.4%, 18.2%, and 17.6%, and we found no significant differences among the three groups possibly due to the limited sample size. Unexpectedly, among participants with complete FDP laceration in Zone I, both circumferential-tendon and circumferential-epitenon sutures caused worsening of TAROM after 2 years. No conclusions can be drawn regarding reoperation rates among the groups. Level of evidence: Therapeutic level I.

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.

Can "In-Out-In" posterosuperior screws meet nutrient foramina in patients with femoral neck fractures?

BACKGROUND

The "In-Out-In" (IOI) posterosuperior screw was common in screw fixations of femoral neck fractures. The impacts of the IOI screw on the blood supply of the femoral head have not yet been clarified. The nutrient foramen was damaged when the screw was present in their corresponding cortex surface. This study aimed to evaluate the damage degrees of the nutrient foramina in the femoral neck as the IOI posterosuperior screw was placed in different posterosuperior locations.

METHODS

One hundred and eight unpaired dry human cadaveric proximal femurs were scanned by a three-dimensional scanner. Digital data obtained from the proximal femur surface were employed for subsequent analysis. All nutrient foramina in the femoral neck were identified and marked in each subject. A simulation of the anteroposterior, lateral, and axial views was then performed, and regions of interest (ROIs) for IOI posterosuperior screws, with 6.5 mm diameter, were determined in the posterosuperior femoral neck on the axial graphs. Nutrient foramina were counted and analyzed in ROIs and femoral neck, and its damage from the IOI posterosuperior screw was also calculated in different conditions of screw placement. Paired t-tests were used for comparative analyses before and after damage.

RESULTS

Most nutrient foramina were located in the subcapital region and the least in the basicervical region in the femoral neck, while the most were located in the transcervical and the least in the subcapital in the ROIs. In addition, most nutrient foramina in ROIs were located in the superior-posterior area of the femoral neck. There were four main locations of IOI posterosuperior screws where the decrease in the nutrient foramina was statistically significant (P < 0.01). The risk zone determined by these locations was located in a posterosuperior square of ROIs with an edge length of 9.75 mm.

CONCLUSION

To minimize iatrogenic damage to the blood supply of the femoral head, screw positions could be assessed in anteroposterior and lateral radiographs using a risk zone. The IOI posterosuperior screw in ROIs can be applied to fix femoral neck fractures when feasible in clinical practice. This study could provide surgeons with more alternatives for screw placement in the posterosuperior femoral neck.

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.

[The identification process of the state of fractures by orthopedic surgeons before radiography]

Fracture treatment requires a detailed understanding of the state and displacement of the fracture site. Before X-ray was discovered by Wilhelm Conrad Röntgen in 1895, it was almost impossible to know the location of the fracture fragments wrapped in skin and muscle. The early classical theories for this were mainly based on the medical theories of Hippocrates and Galen. The more clinical cases were accumulated, the more cases were inconsistent with the classical theories. Doctors either chose to stick to the classics for their diagnose or believed in their own judgment. The development of anatomy gradually became a means of examining fracture fragments. With the development of anatomy during and after the "Renaissance", doctors began to collect a large number of bone specimens and communicated this information to other doctors. Doctors discarded the strict adherence to early classical theories, and finally constructed a theoretical model to explain clinical questions with anatomical evidence.

[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.

[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.

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.

Radiologists with assistance of deep learning can achieve overall accuracy of benign-malignant differentiation of musculoskeletal tumors comparable with that of pre-surgical biopsies in the literature

PURPOSE

The purpose of this study was to assess if radiologists assisted by deep learning (DL) algorithms can achieve diagnostic accuracy comparable to that of pre-surgical biopsies in benign-malignant differentiation of musculoskeletal tumors (MST).

METHODS

We first conducted a systematic review of literature to get the respective overall diagnostic accuracies of fine-needle aspiration biopsy (FNAB) and core needle biopsy (CNB) in differentiating between benign and malignant MST, by synthesizing data from the articles meeting our inclusion criteria. To compared against the accuracies reported in literature, we then invited 4 radiologists, respectively with 2 (A), 6 (B), 7 (C), and 33 (D) years of experience in interpreting musculoskeletal MRI to perform diagnostic tests on our own dataset (n = 62), with and without assistance of a previously developed DL algorithm. The gold standard for benign-malignant differentiation was histopathologic confirmation or clinical/radiographic follow-up.

RESULTS

For FNAB, a meta-analysis containing 4604 samples met the inclusion criteria, with the overall diagnostic accuracy reported to be 0.77. For CNB, an overall accuracy of 0.86 was derived by synthesizing results from 7 original research articles containing a total of 587 samples. On our internal MST dataset, the invited radiologists, respectively, achieved diagnostic accuracies of 0.84 (A), 0.89 (B), 0.87 (C), and 0.90 (D), with the assistance of DL.

CONCLUSION

Use of DL algorithms on musculoskeletal dynamic contrast-enhanced MRI improved the benign-malignant differentiation accuracy of radiologists to a level comparable to that of pre-surgical biopsies. The developed DL algorithms have a potential to lower the risk of miss-diagnosing malignancy in radiological practice.

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.

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.

Association between Weitbrecht's Retinaculum Injury and Femoral Head Necrosis in Femoral Neck Fractures

Objective

To investigate associations between femoral head necrosis (FHN) and injury to the retinaculum of Weitbrecht in patients with femoral neck fractures who had undergone initial trials of either closed reduction or direct open reduction.

Methods

This prospective observational study included 110 patients with displaced femoral neck fractures admitted to the Sixth People's Hospital Affiliated to Shanghai Jiaotong University and Shanghai Tongji Hospital between January 2008 and May 2017. Among these, 25 patients underwent initial closed reductions, and 85 patients underwent an open reduction directly. Watson‐Jones anterolateral approach was used during the surgery for injury to the retinaculum of Weitbrecht, and FHN was assessed as a surgical outcome. The severity of injury to the retinaculum of Weitbrecht was evaluated using a scoring system developed by our surgical team. Follow‐up was at least 24 months.

Results

The initial closed reduction treatment group had significantly higher total scores of injury to the retinaculum of Weitbrecht (6.24 ± 2.20 vs 4.62 ± 2.12, p = 0.009) compared to the open reduction group. High total scores were significantly associated with initial trials of closed reduction treatment, especially for the broken and released injury to the superior and anterior retinacula (both p = 0.01). Twenty‐six patients experienced FHN postoperatively, with mean onset time of 19.42 ± 3.87 months. FHN was significantly associated with the severity of injury to the retinaculum of Weitbrecht (p < 0.001) at the superior, anterior, and inferior retinacula. FHN was significantly associated with injury to the retinaculum of Weitbrecht in females.

Conclusions

Femoral neck displacement in patients treated initially with closed reduction is associated with subsequent injury to the retinaculum of Weibrecht, which may lead to FHN. Severity of injury to the retinaculum of Weibrecht may be used as a biomarker to evaluate bone necrosis in patients with femoral neck fractures.

A quantitative study of bone defects in displaced femoral neck fractures based on virtual reduction techniques

BACKGROUND

Bone defects in femoral neck fractures are strongly associated with the prognosis after internal fixation. However, qualitative analysis of bone defects in femoral neck fractures has already been performed, quantitative studies have not been reported. In this study, we aimed to systematically analyse the morphological characteristics of bone defects in patients with femoral neck fractures using computed tomography (CT) images combined with computer image analysis techniques.

METHODS

Four hundred and sixty-nine patients with femoral neck fractures from January 2014 to December 2018 at two grade A tertiary hospitals were included. Models were created in Mimics software based on CT images collected within 1 week after injury and then imported into 3-matic software for virtual reduction. The volume of the bone defect (VBD), maximum defect thickness (MDT), extent of the bone defect region (EBDR) , main defect quadrant (MDQ), collapse type and fracture classification were calculated and recorded.

RESULTS

The EBDR, collapse type and MDT all had a significant positive effect on the VBD (P <0.05), with a more significant effect at higher quantiles. Age also had a significant positive effect on the VBD (P < 0.05), but its effect was more pronounced at lower quantiles. Compared to non-subcapital fractures, subcapital fractures had a positive effect on the VBD only at the 50 and 75% quantiles (P < 0.01). The female sex had a significant negative effect on the VBD compared to the male sex (P < 0.05).

CONCLUSION

This study established a reliable computer image processing method for quantitative analysis of the VBD in femoral neck fractures and revealed that all patients with femoral neck fractures had bone defects, which can occur at any part of the femoral neck. The EBDR, MDT, collapse type, and patient age and sex were all important risk factors for the extent of the defect and should be taken into account in surgical planning.

Finite element analysis of necessity of reduction and selection of internal fixation for valgus-impacted femoral neck fracture

This study compared the biomechanical characteristics of different treatment strategies based on finite element analysis. Posterior tilt and valgus angle were measured on X-ray from ten valgus-impacted femoral neck fractures, and 7 finite element models that were generated to compare the stress and displacement. The results showed that in the intact femur, von Mises stress was concentrated at the medial and inferior sides of the femoral neck. In valgus-impacted femoral neck fractures, von Mises stress was at the same locations but was 5.66 times higher than that in the intact femur. When 3 cannulated screws were used for internal fixation, anatomic reduction diminished the stress at the fracture end from 140.6 to 59.14 MPa, although displacement increased from 0.228 to 0.450 mm. When the fracture was fixed with a sliding hip screw (SHS) + cannulated screw, there was less stress at the fracture end and greater displacement with anatomic reduction than that without reduction (stress: 15.9 vs 37.9 MPa; displacement: 0.329 vs 0.168 mm). Therefore, the SHS + cannulated screw has superior biomechanical stability than 3 cannulated screws, and is recommended following anatomic reduction to treat valgus-compacted femoral neck fractures.

[Hypoxia promotes differentiation of human induced pluripotent stem cells into embryoid bodies in vitro]

OBJECTIVE

To investigate effects of physiological hypoxic conditions on suspension and adherence of embryoid bodies (EBs) during differentiation of human induced pluripotent stem cells (hiPSCs) and explore the underlying mechanisms.

METHODS

EBs in suspension culture were divided into normoxic (21% O₂) and hypoxic (5% O₂) groups, and those in adherent culture were divided into normoxic, hypoxic and hypoxia + HIF-1α inhibitor (echinomycin) groups. After characterization of the pluripotency with immunofluorescence assay, the hiPSCs were digested and suspended under normoxic and hypoxic conditions for 5 days, and the formation and morphological changes of the EBs were observed microscopically; the expressions of the markers genes of the 3 germ layers in the EBs were detected. The EBs were then inoculated into petri dishes for further culture in normoxic and hypoxic conditions for another 2 days, after which the adhesion and peripheral expansion rate of the adherent EBs were observed; the changes in the expressions of HIF-1α, β-catenin and VEGFA were detected in response to hypoxic culture and echinomycin treatment.

RESULTS

The EBs cultured in normoxic and hypoxic conditions were all capable of differentiation into the 3 germ layers. The EBs cultured in hypoxic conditions showed reduced apoptotic debris around them with earlier appearance of cystic EBs and more uniform sizes as compared with those in normoxic culture. Hypoxic culture induced more adherent EBs than normoxic culture (P < 0.05) with also a greater outgrowth rate of the adherent EBs (P < 0.05). The EBs in hypoxic culture showed significantly up-regulated mRNA expressions of β-catenin and VEGFA (P < 0.05) and protein expressions of HIF-1 α, β-catenin and VEGFA (P < 0.05), and their protein expresisons levels were significantly lowered after treatment with echinomycin (P < 0.05).

CONCLUSION

Hypoxia can promote the formation and maturation of suspended EBs and enhance their adherence and post-adherent proliferation without affecting their pluripotency for differentiation into all the 3 germ layers. Our results provide preliminary evidence that activation of HIF-1α/β-catenin/VEGFA signaling pathway can enhance the differentiation potential of hiPSCs.

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.

Ankle joint pressure change before and after subtalar joint arthrodesis in varus and valgus malalignment of the tibia

Purpose: The compensation mechanism of subtalar joint in ankle with varus or valgus deformity is controversial and not well established. This biomechanical study aims to investigate how subtalar joint arthrodesis will affect the ankle joint pressure in varus and valgus malalignment of the tibia. Methods: Eight fresh-frozen human cadaver legs were tested in this study. A custom-made fixture was utilized and a total of 600N was applied to simulate weight-bearing. Intra-articular sensors (TeckScan) were inserted in the ankle joint to demonstrate the ankle joint pressure. Conditions include: Neutral, 5°, 10°, 15° and 20° varus, 5°, 10°, 15° and 20° valgus. Results: After the fusion of the subtalar joint, when the tibia is gradually inverted, the inside pressure of the ankle joint gradually increases, and the pressure on the outside of the ankle joint gradually decreases. When the tibia is gradually eversion, the pressure on the outside of the ankle joint gradually increases, and the inside of the ankle joint gradually decreases. Conclusions: After the subtalar joint is fused, the compensatory activity of the subtalar joint disappears, and the regulation of the pressure in the ankle joint will be lost. We hypothesized that the inversion compensation of the subtalar joint is more likely to occur than the eversion compensation.

3D Mapping of Bone Channel of Blood Supply to Femoral Head in Proximal Femur

Background

A detailed depiction of nutrient foramina is useful for defining guidelines and minimising iatrogenic damage during hip surgery. Therefore, this study aimed to define the location and frequency of nutrient foramina in the proximal femur using mapping techniques.

Methods

One hundred dry human cadaveric proximal femurs, comprising 56 left and 44 right femurs, were scanned using a three-dimensional scanner, with scanning distance 200 mm, precision 0.01 mm, and measuring point 0.04 mm. The image resolution of 1,310,000 pixels was obtained. Digital imaging models were acquired from the proximal femur surface. All the nutrient foramina in each model were identified and marked. The nutrient foramina models were superimposed on one another and oriented to fit a standard template of the femur’s proximal aspect. Three-dimensional mapping in the proximal femur’s nutrient foramina was performed.

Results

The nutrient foramina’s location and dense zones were identified. The dense zones were distributed along the vascular course and gaps between the muscle attachment sites. Eighteen dense zones were identified and found to be location-dependent. They were located in the central part of the fovea capitis femoris, subcapital and basicervical areas of the femoral neck, and muscle attachment gaps of the femoral trochanter.

Conclusions

The terminal branch of the nutrient vessels entering the nutrient foramina is at risk for iatrogenic damage during hip surgeries, especially in cases of close bone exposures. There are 18 dense zones that need to be considered for a safer approach to the proximal femur. To minimise iatrogenic damage to the nutrient vessels entering the nutrient foramina, the dense areas should be avoided when technically possible.

A finite element analysis study based on valgus impacted femoral neck fracture under diverse stances

The aim of the study was to determine the biomechanical environment of patients who suffer from valgus impacted femoral neck fracture. With the help of computational modeling, both of finite element hip fracture and normal three-dimensional model were reconstructed from a patient with hip fracture. The predicted stress distribution was compared between before and after fracture. After the fracture, during standing and the gait, the fracture site has a greater change in stress distribution due to the shortening of the femoral neck. The largest stress occurs at the middle and lower end of the femoral shaft, which occurs from toe off to deceleration during the whole gait. After the fracture, greater stress on the femoral head will result in a worse mechanical environment for the femur. The stress peak value of the femoral shaft is larger than the unfractured side and the stress distribution is uneven. From the results of gait analysis, it is concluded that the increase of concentrated stress and the change of stress distribution will cause the possibility of secondary fractures at the middle and lower ends of the femoral shaft when there is an accident in the case of existing fracture.

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.

Fracture morphology and biomechanical characteristics of Pauwels III femoral neck fractures in young adults

BACKGROUND

Pauwels classification, which categorizes types of femoral neck fractures, cannot fully reflect the three-dimensional characteristics of this injury. The purpose of our study was to determine the morphological characteristics of Pauwels III fractures through computed tomography image analysis and summarize the relevant biomechanical characteristics of different morphological fractures.

METHODS

We retrospectively reviewed a total of 209 patients diagnosed with Pauwels type III femoral neck fractures. Fracture reduction was simulated based on mirror symmetry of the bilateral femur by Mimics. The fracture angle was measured and subtypes were defined. Biomechanical characteristics were compared by finite element analysis and validated using a biomechanical experiment, which was performed on a cadaveric sample.

RESULTS

Pauwels III femoral neck fractures can be divided into three subtypes: anterior, posterior, and classical. The proportion of three subtypes was 28.71%, 67.46%, and 3.82%, respectively. The anterior subtype showed the lowest axial stiffness but highest implant and bone stress. High stress distributions was concentrated on the screw-bone interface and screw-plate connections.

CONCLUSIONS

Biomechanical differences across the three subtypes of Pauwels III femoral neck fractures could increase our understanding of the biomechanical characteristics that underlie the Pauwels type III femoral neck fractures (such as, three-dimensional morphology and the stress distribution of bone and implant) that have been associated with high failure rates.

Superior Mid- to Long-Term Clinical Outcomes of Mobile-Bearing Total Knee Arthroplasty Compared to Fixed-Bearing: A Meta-Analysis Based on a Minimum of 5 Years of Study

As more patients undergo total knee arthroplasty (TKA) each year, and the average age of patients gets younger, the patients are generally more active requiring a greater physiological demand and increasing range of motion on the prosthesis than the previous patients. However, there is no consensus on the optimal TKA tibial bearing design. We performed this systematic review to compare the clinical differences between mobile and fixed bearing constructs used in contemporary TKA. We searched PubMed, EMBASE, and Cochrane Library databases, identifying 515 total publications, including 17 randomized controlled trials (RCTs). A meta-analysis was performed, while the quality and bias of the evidence were rated according to the Grading of Recommendations Assessment Development and Evaluation (GRADE) guidelines and the Cochrane Database questionnaire. The meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Seventeen studies were included, with a total of 1505 knees receiving a mobile bearing TKA and 1550 knees receiving a fixed bearing TKA. The meta-analysis compared clinical outcomes between mobile bearing (MB)-TKA and fixed bearing (FB)-TKA using postoperative Knee Society Score, postoperative ROM, and survivorship and showed that there was a distinct difference in Knee Society Score between the mobile-bearing and fixed-bearing groups (overall standardized mean difference = 1.38; 95% confidence interval (CI): 0.50-2.25; p = 0.002; I² = 60%). Patients treated with mobile-bearing prostheses were more likely to report good or excellent range of motion results (overall standardized mean difference = 2.06; 95% CI: 0.65-3.47; p = 0.004). No difference in implant survivorship or reoperation rate were identified. The fixed-bearing and mobile-bearing TKA designs are both capable of producing excellent long-term results with excellent clinical outcomes if properly implanted; however, the mobile-bearing TKA have superiority in mid- to long-term clinical results. Trial registration number for PROSPERO was CRD42019126402.

Malignant fibrous histiocytoma of the bone in a traumatic amputation stump: A case report and review of the literature

BACKGROUND

Malignant fibrous histiocytoma (MFH) is one of the most common soft tissue sarcomas among adults. It is characterized by large size, high grade, and biological aggressiveness. There are many reports of MFH after local stimulation, such as bone fracture, implants, and chronic osteomyelitis. In this paper, we report a patient who developed MFH 6 years after amputation, suggesting that wound healing and mechanical force play a role in the local stimulation of this disease.

CASE SUMMARY

A 66-year-old man complained of persistent pain in his residual mid-thigh. He had undergone amputation surgery due to a traffic accident 6 years prior. Physical examination showed tenderness but no abnormalities in appearance. X-ray radiographs and magnetic resonance imaging supported the diagnosis of a tumor, and a biopsy confirmed that the lesion was MFH. The patient received neoadjuvant chemotherapy and left hip disarticulation. During the 6-mo follow-up, there were no symptoms of recurrence.

CONCLUSION

Postsurgery MFH has been reported before, and many studies have attributed it to the biological effects of implants. Our case report shows that this disease can develop without an implant and thus highlights the importance of local stimulation. The wound-healing process and mechanical force can both promote this tumor, but whether they directly cause MFH needs further investigation.

Zinc oxide nanoparticles promotes liver cancer cell apoptosis through inducing autophagy and promoting p53

OBJECTIVE

Emerging evidence has highlighted the promising potential of the application of Zinc Oxide nanoparticles (nano-ZnO) but the mechanism by how it functions in liver cancer remains elusive. We aimed to explore the effect of nano-ZnO on liver cancer cells.

MATERIALS AND METHODS

Liver cancer cells Huh7 cells were transfected with GFP-LC3, and then, treated with DMSO, Sorafenib, and nano-ZnO respectively to set blank group, Sorafenib control group, and nano-ZnO group followed by the analysis of the expression of GFP-LC3, p53, and Caspase by Western blot and RT-qPCR, cell apoptosis and viability by flow cytometry and CCK-8 assay.

RESULTS

With a diameter of nano-ZnO 14.13±0.92 nm, the amount of GFP-LC3 protein was increased after treatment of nano-ZnO. Besides, the expressions of GFP-LC3, p53, and Caspase in Sorafenib group and nano-ZnO group were significantly higher than that of control group, while their levels were highest in nano-ZnO group (p<0.05). In nano-ZnO group, the values of D450nm at 24 h, 48h, and 72 h were 0.56±0.06, 0.39±0.05, and 0.22±0.04, respectively, and the apoptotic rate (83.11±2.79%) was significantly lower than that of blank group and control group.

CONCLUSIONS

Nano-ZnO induced autophagy, upregulated the p53 gene, and facilitated the apoptosis of liver cancer cells, indicating that nano-ZnO might be a therapeutic approach for the treatment of liver cancer patients.

Insufficient blood supply of fovea capitis femoris, a risk factor of femoral head osteonecrosis

Background

A defective nutrient foramen in the fovea capitis femoris was hypothesized to reflect the blood circulation pattern of the femoral head, leading to insufficient blood supply and causing osteonecrosis of the femoral head.

Methods

Normal and necrotic femoral head specimens were collected. The necrotic femoral head group was divided into a non-traumatic and traumatic subgroup. 3D scanning was applied to read the number, the diameter, and the total cross-sectional area of the nutrient foramina in the fovea capitis femoris. Chi-squared tests and independent t-tests were used to detect any differences in the categorical and continuous demographic variables. Logistic regression models were used to estimate the odds ratio (OR) for non-traumatic and traumatic osteonecrosis in different characteristic comparisons.

Results

A total of 249 femoral head specimens were collected, including 100 normal femoral heads and 149 necrotic femoral heads. The necrotic femoral head group revealed a significantly higher percentage of no nutrient foramen (p < 0.001), a smaller total area of nutrient foramina (p < 0.001), a smaller mean area of nutrient foramina (p = 0.014), a lower maximum diameter of the nutrient foramen (p < 0.001), and a lower minimum diameter of the nutrient foramen (p < 0.001) than the normal femoral head group. The logistic regression model demonstrated an increasing number of nutrient foramina (crude OR, 0.51; p < 0.001), a larger total area of nutrient foramina (crude OR, 0.58; p < 0.001), a larger mean area of nutrient foramina (crude OR, 0.52; p = 0.023), a greater maximum diameter of the nutrient foramen (crude OR, 0.26; p < 0.001), and greater minimum diameter of the nutrient foramen (crude OR, 0.20; p < 0.001) significantly associated with reduced odds of osteonecrosis of the femoral head (ONFH). The necrotic femoral head group was further divided into 118 non-traumatic and 31 traumatic necrotic subgroups, and no significant difference was observed in any characteristics between them.

Conclusions

Characteristics of the nutrient foramen in the fovea capitis femoris showed a significant defect of necrotic than normal femoral heads, and significantly reduced odds were associated with the higher abundance of the nutrient foramen in ONFH. Therefore, the condition of the nutrient foramen might be the indicator of ONFH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02564-6.

A three-dimensional measurement based on CT for the posterior tilt with ideal inter-and intra-observer reliability in non-displaced femoral neck fractures

Posterior tilt is associated with prognosis of non-displaced femoral neck fractures (FNFs). Knowledge of their association is critical and informs surgeons whether to choose internal fixation or arthroplasty in treatment of non-displaced FNFs. This study aimed to design a novel three-dimensional (3D) posterior tilt measurement and evaluate the intra- and inter-observer variability compared to two-dimensional (2D) measurement proposed by Palm. We hypothesized that 3D measurement would be more accurate and realistic with higher reliability. To test the hypothesis, three observers measured the posterior tilt on the radiographs of 50 non-displaced FNFs, twice with both methods. Intra- and inter-observer reliability for each measurement method used were determined. The measured angle was divided into two categories, at the cut-off of 20° for clinical practice simulation. Intra- and inter-observer reliability were identified for clinical effectiveness. The results indicated that inter- and intra-observer reliability for 3D measurement and its classification was almost perfect with an intraclass coefficient of 0.995 (0.994) and a kappa value of 0.927(0.947), respectively. Conversely, a substantial inter- and intra-observer reliability for the 2D measurement was obtained with an interclass coefficient of 0.764 as well as an intraclass coefficient of 0.773. The clinical validity for 2D measurement showed slight inter-reliability and moderate intra-reliability with a kappa value of 0.192 and 0.587, respectively. Hence, the novel 3D measurement appears to be more reliable with a strong inter- and intra-observer reliability measurement. Further clinical studies are needed to carry out to validate this hypothesis.

Fracture mapping of complex intra-articular calcaneal fractures

Background

Intra-articular calcaneal fracture remains challenging to manage. Computed tomography and fracture mapping are useful for the diagnosis and treatment of calcaneal fractures. The aim of the present study was to characterize calcaneal fracture patterns using fracture mapping.

Methods

Sixty-two calcaneal fractures were retrospectively included in the study. For each case, the fracture was simulated reduction manually. The fracture lines and zones of comminution were graphically superimposed onto an intact calcaneal template to identify fracture patterns. Major fracture lines and comminution were assessed by focusing on the posterior joint facet, medial wall, lateral wall, sustentaculum tali, and anterior process.

Results

The fracture lines were mostly concentrated on the area anterior to the posterior joint facet and extended medially. The longitudinal lines ran posteriorly from the angle of Gissane, and separated the sustentaculum tali and medial wall from the calcaneal tuberosity. In the lateral wall, the fracture lines extended posteriorly with some branches to the bottom of the calcaneus. No fracture lines passed through the sustentaculum tali. Fracture lines of the posterior tuberosity and anterior process were rare.

Conclusions

Calcaneal fracture lines follow characteristic patterns, which are closely related to the bone structure and fracture mechanism. These fracture patterns will aid clinicians choose surgical approach and fixations in the treatment of calcaneal fractures.

Biomechanical analysis of "Barrel hoop plate" technique for the posterolateral fragments of tibial plateau fractures with different displacement tendency

OBJECTIVES

The purpose of our study is to evaluate the three-dimensional biomechanical properties of "Barrel Hoop plate" in two kinds of artificial posterolateral tibial plateau fracture fragment (PLF) by using of synthetic models, each of which has an initial amplifying displacement tendency.

MATERIAL AND METHODS

Thirty-six tibiae models were randomly assigned into two groups with different displacement tendencies: posterior displacement (PD) and lateral displacement (LD). Each model was then fixed with three patterns: Anterolateral plate (AP), Posterolateral plate (PP), and "Barrel Hoop plate" (BHP). Displacement in three axes of vertical, sagittal and horizontal axis was captured by Optotrak Certus motion analysis system. Bluehill 2 software was used for load control and data collection.

RESULTS

In Model-PD, when the load was over 1000 N, the posterior displacement of Group-PP and Group-BHP were less than Group-AP (P<0.01). The inferior displacement in the vertical axis of Group-PP was larger than both Group-AP and Group-BHP in all the loading set (P<0.01). In Model-LD, both of the lateral displacement in Group-AP and Group-BHP was less than that of Group-PP when the load was over 1000 N (P<0.01). The inferior displacement of Group-AP was less than that of Group-PP in the load of 1500 N (P<0.01). Both of the posterior displacement of Group-AP and Group-BHP was less than that of Group-PP when the loading was 1500 N (P<0.01). The stiffness of Group PP was less than that of Group AP (P<0.01).

CONCLUSIONS

The results demonstrated that the 2.7 mm "Barrel Hoop plate" had a greater capacity of anti-three-dimension axes displacement of PLF. The 3.5 mm Anterolateral plate had the advantage in anti-lateral displacement and anti-inferior displacement but was weak at anti-posterior displacement of PLF. The 2.7 mm Posterolateral plate was stronger in anti-posterior, however, weak in anti-inferior displacement capacity.

Effect of combined treatment with pulsed electromagnetic field stimulation and sclerostin monoclonal antibody on changes in bone metabolism and pedicle screw augmentation in rabbits with ovariectomy-induced osteoporosis

BACKGROUND

Both pulsed electromagnetic field (PEMF) stimulation and sclerostin monoclonal antibody are useful for treating osteoporosis, but whether the two therapies have synergistic effects on both screw fixation quality and bone metabolism of ovariectomy-induced osteoporosis has not been reported.

METHODS

We used ovariectomy to create a rabbit model of postmenopausal osteoporosis. Then, specimens were fixed with pedicle screws in the L4 vertebral body. Rabbits were randomly divided into an OVX control group, PEMF group, Scl-Ab group, and PEMF+Scl-Ab group. The PEMF group was given PEMF magnetic therapy, the Scl-Ab group was administered a subcutaneous Scl-Ab injection, and the PEMF+SclAb group received both therapies. The OVX group was injected subcutaneously with the same dose of saline instead. After eight weeks of treatment, the bone metabolism index, bone mineral density (BMD), and bone microstructural, biological, and biomechanical parameters were evaluated.

RESULTS

BMD significantly decreased six months post-ovariectomy. Compared with that of the OVX group, the BMD of the PEMF, Scl-Ab, and PEMF+Scl-Ab groups increased by 20.3%, 19.9%, and 35.0%, respectively. The maximum pulling force of pedicle screws increased by 14.0%,15.0% and 19.1%, and the maximum failure power consumption of pedicle screws increased by 27.9%, 27.2% and 33.6%, respectively; these differences were statistically significant (P<0.05). The bone metabolism index and bone microstructure parameters of the PEMF+Scl-Ab group were more optimal than those in the single treatment group.

CONCLUSIONS

Both Scl-Ab and PEMF therapy can enhance the BMD and the mechanical strength of pedicle screws in osteoporotic bones of rabbits with postmenopausal osteoporosis. However, combination of the two measures has achieved even better results, yielding potential clinical application value.

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.

Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.

Biomechanical analysis of four augmented fixations of plate osteosynthesis for comminuted mid-shaft clavicle fracture: A finite element approach

Sufficient stabilization of comminuted mid-shaft clavicle fractures via plate fixation is difficult to achieve. Various augmentations, including interfragmentary screws and cerclage wiring, have been adopted to reinforce fixation stability. The present study aimed to assess the biomechanical stability of augmented plate fixations using the finite element method. First, a clavicle fracture model was created from CT data. Fixation was then induced using a locking compressive plate (LCP) with the following four augmentations: i) Double inner cerclage wirings (DICW), ii) double outer cerclage wirings (DOCW), iii) a single interfragmentary screw (SIS) and iv) double interfragmentary screws (DIS). Compressive and bending forces of 100 N were subsequently applied at the acromial region of the clavicle. The stress distribution, displacement and fracture micro-motions of the model were assessed and compared. The DOCW resulted in the highest stress exerted on the LCP, followed by SIS, DICW and DIS. For the clavicle fracture, DICW, DOCW and SIS resulted in high stress levels. However, DIS fixation alone resulted in levels of stress that were below the yield strength of cortical bone. Displacement analysis revealed that DOCW fixation resulted in the greatest degree of displacement and fracture micro-motions, followed by SIS, DICW and DIS. The results indicated that SIS, DIS and DOCW may be used as augmentations of LCP fixation for comminuted mid-shaft clavicle fractures. However, DIS was the recommended augmentation due to it exerting the lowest stress and the highest stability compared with the other fixations. The DICW may be used to aid fracture reduction and plate placement in surgery but should be avoided for permanent fixation.

Identification of human temporomandibular joint fibrocartilage stem cells with distinct chondrogenic capacity

OBJECTIVE

This study was aimed to identify the residence of human fibrocartilage stem cells (hFCSCs), characterize their stem cell properties and investigate the functional mechanisms which regulate fibrocartilage stem cells (FCSCs) toward chondrogenic differentiation during cartilage homeostasis and repairing.

METHODS

Cytological characteristics of hFCSCs and human orofacial mesenchymal stem cells (hOFMSCs) were analyzed. Chondrogenic potential of hFCSCs was compared with hOFMSCs both in vitro and in vivo. Regulatory role of SOX9 during FCSCs chondrogenesis was studied by shRNA interference in vitro, and by GFP⁺ FCSCs treatment in rat condylar cartilage defect model. SOX9 expression was also examined in temporomandibular joint osteoarthritis (TMJOA) patients' cartilage surface.

RESULTS

hFCSCs exhibited typical mesenchymal stem cell characteristics, with significantly stronger chondrogenic capability compared to hOFMSCs. Moreover, hFCSCs showed remarkably increased expression of SOX9. During cartilage pellet culture, there was stronger SOX9 expression in hFCSCs than hOFMSCs. SOX9 shRNA interference downregulated chondrogenic capability of hFCSCs in vitro, as well as disrupting migration and chondrogenic differentiation of GFP⁺ FCSCs toward mature chondrocytes in rat condylar cartilage defect. Of note, SOX9 expression was also found suppressed in the condylar superficial zone of TMJOA patients.

CONCLUSION

We found the existence of FCSCs in human TMJ cartilage, and characterized their distinct stem cell features. SOX9 is essential for hFCSCs chondrogenic differentiation, and a comprehensive understanding of the regulatory role of SOX9 in hFCSCs would be important for exploring potential intervention strategy of condylar cartilage degradation during TMJ disorders.

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.

An energy efficient time-mode digit classification neural network implementation

This paper presents the design of an ultra-low energy neural network that uses time-mode signal processing). Handwritten digit classification using a single-layer artificial neural network (ANN) with a Softmin-based activation function is described as an implementation example. To realize time-mode operation, the presented design makes use of monostable multivibrator-based multiplying analogue-to-time converters, fixed-width pulse generators and basic digital gates. The time-mode digit classification ANN was designed in a standard CMOS 0.18 μm IC process and operates from a supply voltage of 0.6 V. The system operates on the MNIST database of handwritten digits with quantized neuron weights and has a classification accuracy of 88%, which is typical for single-layer ANNs, while dissipating 65.74 pJ per classification with a speed of 2.37 k classifications per second. This article is part of the theme issue 'Harmonizing energy-autonomous computing and intelligence'.

Total cross-sectional area of the femoral neck nutrient foramina measured to assess arterial vascular beds in the femoral head

Background

A detailed understanding of the blood supply to the femoral head is required to plan the surgery in the femoral neck and head area. However, information about the blood vessel networks in the femoral head is inadequate.

Methods

The surface of the femoral neck of 100 dry cadaveric adult femur specimens was scanned using a 3D scanner. The scanning distance was 200 mm, precision 0.01 mm, and measuring point 0.04 mm. The images were acquired at a resolution of 1,310,000 pixels. Digital imaging data were recorded from the femoral neck surface. The diameters of the nutrient foramina of the superior, inferior and anterior retinacular arteries, and the ligamentum teres arteries were determined and divided into five groups.

Results

The mean cumulative cross-sectional area of the nutrient foramina was as follows: canals of the superior, inferior, anterior, and ligamentum retinacular arteries were 15.59 mm², 3.63 mm², 4.32 mm², and 1.58 mm², respectively. Next, we analyzed the canals of the superior, inferior, anterior and ligamentum retinacular arteries, respectively, via 3D scanner. We found that the canals of the superior retinacular arteries appear to supply more blood to the femoral head than the canals of the other three types of arteries.

Conclusions

Our results demonstrated that surgeries of the femoral neck and femoral head will be improved with prior 3D scanning and lead to better outcomes in surgeries involving the hip area.

[Protective effect of excretory-secretory protein from adult Trichinella spiralis on ovalbumin-induced allergic rhinitis in mice]

OBJECTIVE

To investigate the protective effect of excretory-secretory protein (AES) from adult Trichinella spiralis on ovalbumin (OVA)-induced allergic rhinitis in mice.

METHODS

Eighteen female BALB/c mice were randomly divided into three groups, including the blank control group (Group A), OVA-induced rhinitis group (Group B) and AES treatment group (Group C). Mice in Group A were given PBS. Mice in Group B were intraperitoneally injected with antigen adjuvant suspension for systemic sensitization, once every other day for seven times; then, local excitation was intranasally induced with 5% OVA solution once a day for seven times to establish a mouse model of allergic rhinitis. In addition to induction of allergic rhinitis, mice in Group C were given 25 μg AES at baseline sensitization and local excitation. Following the final challenge, mice were observed for 30 min in each group, and the behavioral score was evaluated. The serum levels of IFN-γ, IL-4, IL-5, IL-10 and TGF-β were determined using an enzyme-linked immunosorbent assay in mice, and the pathological changes of mouse nasal mucosa were observed under a microscope.

RESULTS

There was a significant difference in the mouse behavioral scores among the three groups (F = 110.12, P < 0.01). The mouse behavioral score was significantly higher in Group B than in Group A (7.17 ± 0.75 vs. 1.33 ± 0.52, P < 0.01), and more remarkable pathological damages of mouse nasal mucosa were seen in Group B than in Group A, while the mouse behavioral score was significantly decreased in Group C than in Group B (P < 0.01), and the pathological damages of mouse nasal mucosa remarkably alleviated in Group C relative to Group B. There was a significant difference in serum IFN-γ level among the three groups (F = 7.50, P < 0.01) and the serum IFN-γ level in Group B was significantly lower than in group A and C (both P < 0.05). There were significant differences in serum IL-4 (F = 470.81, P < 0.01) and IL-5 levels (F =68.20, P < 0.01) among the three groups, and significantly greater serum IL-4 and IL-5 levels were detected in Group B than in Group A (P < 0.01), while significantly lower serum IL-4 and IL-5 levels were detected in Group C than in Group B (P < 0.01). There were significant differences in serum IL-10 (F = 174.91, P < 0.01) and TGF-β levels (F = 9.39, P < 0.01) among the three groups, and significantly greater serum IL-10 and TGF-β levels were seen in Group C than in Group B (both P < 0.05).

CONCLUSIONS

T. spiralis AES has a remarkable protective activity against OVA-induced allergic rhinitis in mice.

MicroRNA-200c suppressed cervical cancer cell metastasis and growth via targeting MAP4K4

OBJECTIVE

To dissect the functioning mode of miR-200c on cervical cancer cell metastasis and growth and provide therapeutic targets for cervical cancer.

PATIENTS AND METHODS

By quantitative Real-time polymerase chain reaction, the miR-200c expression level in 42 pairs of cervical cancer tissue samples and six cervical cancer-derived cell lines were examined. Using miR-200c mimics, we analyzed the effects of miR-200c over-expression on cell proliferation, invasion, and migration. Dual-luciferase activity assay was recruited to examine the potential target gene MAP4K4 that predicted by several databases. Protein level was studied using Western blot.

RESULTS

miR-200c expressed significantly lower in cervical cancer tissue samples and cell lines. And over-expression of miR-200c in cervical cancer cells significantly decreased the cell invasion, migration and proliferation abilities. Dual-luciferase and Western blot confirmed MAP4K4 as a target gene of miR-200c. Furthermore, up-regulation of MAP4K4 counteracted the suppressive effect of miR-200c over-expression on cell growth and metastasis.

CONCLUSIONS

miR-200c could suppress cervical cancer cell proliferation and progression via regulating MAP4K4, which might provide a new target for cervical cancer diagnosis and therapy.