The development and external validation of a web-based nomogram for predicting overall survival with Ewing sarcoma in children.

Background: Ewing sarcoma remains the second most prevalent primary aggressive bone tumor in teens and young adults. The aim of our study was to develop and validate a web-based nomogram to predict the overall survival for Ewing sarcoma in children. Methods: A total of 698 patients, with 640 cases from the Surveillance, Epidemiology, and End Results (the training set) and 58 cases (the external validation set), were included in this study. Cox analyses were carried out to determine the independent prognostic indicators, which were further included to establish a web-based nomogram. The predictive abilities were tested through the concordance index, calibration curve, decision curve analysis, and area under the receiver operating characteristic curve. Results: As suggested by univariate and multivariate Cox analyses, age, primary site, tumor size, metastasis stage (M stage), and chemotherapy were included as the independent predictive variables. The area under the receiver operating characteristic curve values, calibration curves, concordance index, and decision curve analysis from training and validation groups suggested the model has great clinical applications. Conclusion: We developed a convenient and precise web-based nomogram to evaluate overall survival for Ewing sarcoma in children. The application of this nomogram would assist physicians and patients in making decisions.

Unraveling Key m6A Modification Regulators Signatures in Postmenopausal Osteoporosis through Bioinformatics and Experimental Verification.

OBJECTIVE: Bone marrow mesenchymal stem cells (BMSCs) show significant potential for osteogenic differentiation. However, the underlying mechanisms of osteogenic capability in osteoporosis-derived BMSCs (OP-BMSCs) remain unclear. This study aims to explore the impact of YTHDF3 (YTH N6-methyladenosine RNA binding protein 3) on the osteogenic traits of OP-BMSCs and identify potential therapeutic targets to boost their bone formation ability. METHODS: We examined microarray datasets (GSE35956 and GSE35958) from the Gene Expression Omnibus (GEO) to identify potential m6A regulators in osteoporosis (OP). Employing differential, protein interaction, and machine learning analyses, we pinpointed critical hub genes linked to OP. We further probed the relationship between these genes and OP using single-cell analysis, immune infiltration assessment, and Mendelian randomization. Our in vivo and in vitro experiments validated the expression and functionality of the key hub gene. RESULTS: Differential analysis revealed seven key hub genes related to OP, with YTHDF3 as a central player, supported by protein interaction analysis and machine learning methodologies. Subsequent single-cell, immune infiltration, and Mendelian randomization studies consistently validated YTHDF3's significant link to osteoporosis. YTHDF3 levels are significantly reduced in femoral head tissue from postmenopausal osteoporosis (PMOP) patients and femoral bone tissue from PMOP mice. Additionally, silencing YTHDF3 in OP-BMSCs substantially impedes their proliferation and differentiation. CONCLUSION: YTHDF3 may be implicated in the pathogenesis of OP by regulating the proliferation and osteogenic differentiation of OP-BMSCs.

Do Age and Timing Influence the Outcomes of Single-stage Reconstruction of Multiple Ligament Knee Injuries? 5-10 Years Follow Up.

OBJECTIVES: Multiple ligament knee injuries (MLKIs) are disruptive injuries, however, there are controversies in the results of acute and delayed reconstruction. Also, clinical outcomes between patients older or younger than 40 have not been compared in MLKIs. This study was designed to investigate the influence of age and timing of reconstruction on the outcomes of single-stage reconstruction of MLKIs. METHODS: The patients who underwent reconstruction of multiple injured ligaments because of MLKIs between May 2013 and July 2019 were added to the cohort. The postoperative complications, knee range of motion (ROM), Lysholm score, International Knee Documentation Committee (IKDC) 2000 score, Tegner activity level, patient satisfaction, and SF-36 score were compared between young (≤ 40 years old, n = 41) and old patients (n = 61); acute (≤ 3 weeks after injury, n = 75) and delayed reconstruction (n = 27), using Mann-Whitney U test or χ2 test. RESULTS: A total of 102 MLKI patients managed by single-stage multi-ligament reconstruction were retrospectively reviewed. Patients were followed up after surgery for a mean of 7.3 years (5.2-10.7 years). At the last follow-up, no significant difference was found in knee ROM, functional scores, and patient-reported outcomes between patients older or younger than 40; acute and delayed reconstruction (p > 0.05). The rate of complications in the delayed reconstruction group was higher than that of the acute reconstruction group (22.2% vs 5.3%, p < 0.05). The IKDC objective scores reached grade A in 63.7%-80.4% of patients, and grade B in 11.8%-23.5% patients. CONCLUSION: The single-stage reconstruction of MLKIs can obtain comparative long-term functional and objective outcomes regardless of patients older or younger than 40; acute and delayed reconstruction, however, delayed reconstruction is related to a high rate of postoperative complications.

TRPV Channels in Osteoarthritis: A Comprehensive Review.

Osteoarthritis (OA) is a debilitating joint disorder that affects millions of people worldwide. Despite its prevalence, our understanding of the underlying mechanisms remains incomplete. In recent years, transient receptor potential vanilloid (TRPV) channels have emerged as key players in OA pathogenesis. This review provides an in-depth exploration of the role of the TRPV pathway in OA, encompassing its involvement in pain perception, inflammation, and mechanotransduction. Furthermore, we discuss the latest research findings, potential therapeutic strategies, and future directions in the field, shedding light on the multifaceted nature of TRPV channels in OA.

Decreased sagittal slope of the medial tibial spine and deep concavity of the lateral tibial spine are risk factors for noncontact anterior cruciate ligament injury.

PURPOSE: This study aimed to assess the relationship between the geometric features of tibial eminence and susceptibility to noncontact anterior cruciate ligament (ACL) injuries. METHODS: Patients with unilateral noncontact knee injuries between 2015 and 2021 were consecutively enroled in this study. Based on knee magnetic resonance imaging (MRI) and arthroscopic visualisation, patients were categorised into the case group (ACL rupture) and control group (ACL intact). Using MRI, the geometric features of tibial eminence were characterised by measuring the sagittal slopes, depth of concavity and coronal slopes of the inclined surfaces of the tibial spines. Univariate and multivariate logistic regressions were conducted to explore independent associations between quantified geometric indices of tibial eminence and the risk of noncontact ACL injuries. RESULTS: This study included 187 cases and 199 controls. A decreased sagittal slope of the medial tibial spine (MTSSS) (combined group: odds ratio [OR]: 0.87 [0.82, 0.92], p < 0.001; females: OR: 0.88 [0.80, 0.98], p = 0.020; males: OR: 0.87 [0.81, 0.93], p < 0.001) and an increased depth of concavity in the lateral tibial spine (LTSD) (combined group: OR: 1.51 [1.24, 1.85], p < 0.001; females: OR: 1.65 [1.12, 2.43], p = 0.012; males: OR: 1.44 [1.11, 1.89], p = 0.007) were independent risk factors for noncontact ACL injuries. Moreover, a steeper coronal slope of the inclined surface of the medial tibial spine was a significant predictor of noncontact ACL injuries for males (MTSCS: OR: 1.04 [1.01, 1.08], p = 0.015) but not for females. CONCLUSION: Geometric features of tibial eminence, particularly a decreased MTSSS and an increased LTSD, were identified as independent risk factors for noncontact ACL injuries. These findings will help clinicians identify individuals at high risk of ACL injury and facilitate the development of targeted prevention strategies. LEVEL OF EVIDENCE: Level III.

Murepavadin promotes the killing efficacies of aminoglycoside antibiotics against Pseudomonas aeruginosa by enhancing membrane potential.

Murepavadin is a peptidomimetic that specifically targets the lipopolysaccharide transport protein LptD of Pseudomonas aeruginosa. Here, we found that murepavadin enhances the bactericidal efficacies of tobramycin and amikacin. We further demonstrated that murepavadin enhances bacterial respiration activity and subsequent membrane potential, which promotes intracellular uptake of aminoglycoside antibiotics. In addition, the murepavadin-amikacin combination displayed a synergistic bactericidal effect in a murine pneumonia model.

METTL3-mediated m6A modification increases Hspa1a stability to inhibit osteoblast aging.

Senile osteoporosis is mainly caused by osteoblasts attenuation, which results in reduced bone mass and disrupted bone remodeling. Numerous studies have focused on the regulatory role of m6A modification in osteoporosis; however, most of the studies have investigated the differentiation of bone marrow mesenchymal stem cells (BMSCs), while the direct regulatory mechanism of m6A on osteoblasts remains unknown. This study revealed that the progression of senile osteoporosis is closely related to the downregulation of m6A modification and methyltransferase-like 3 (METTL3). Overexpression of METTL3 inhibits osteoblast aging. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) revealed that METTL3 upregulates the stability of Hspa1a mRNA, thereby inhibiting osteoblast aging. Moreover, the results demonstrated that METTL3 enhances the stability of Hspa1a mRNA via m6A modification to regulate osteoblast aging. Notably, YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) participates in stabilizing Hspa1a mRNA in the METTL3-mediated m6A modification process, rather than the well-known degradation function. Mechanistically, METTL3 increases the stability of Hspa1a mRNA in a YTHDF2-dependent manner to inhibit osteoblast aging. Our results confirmed the significant role of METTL3 in osteoblast aging and suggested that METTL3 could be a potential therapeutic target for senile osteoporosis.

A novel mechanism of Vildagliptin in regulating bone metabolism and mitigating osteoporosis.

Osteoporosis has become a global social problem with the tendency toward the aging population. The challenge in managing osteoporosis is to develop new anti-osteoporosis drugs that target bone anabolism. The purpose of this study was to uncover the novel mechanism of Vildagliptin on bone metabolism. We revealed that Vildagliptin significantly promoted osteogenic differentiation of precursor osteoblasts and bone marrow mesenchymal stem cells (BMSCs). At the same time, it significantly enhanced the polarization of RAW264.7 macrophages to the M2 type and the secretion of osteogenic factors BMP2 and TGF-ß1. This was confirmed by the increased osteogenic differentiation observed in the osteoblast-RAW264.7 co-culture system. Moreover, Vildagliptin significantly enhanced the transformation of BMSCs into the osteogenic morphology in the osteoblast-BMSC co-culture system. Finally, Vildagliptin also inhibited osteoclastic differentiation of RAW 264.7 cells. The potential mechanism underlying these effects involved targeting the GAS6/AXL/ERK5 pathway. In the in vivo study, Vildagliptin significantly alleviated postmenopausal osteoporosis in ovariectomized mice. These findings represent the first comprehensive revelation of the regulatory effect of Vildagliptin on bone metabolism. Specifically, Vildagliptin demonstrates the ability to promote bone anabolism and inhibit bone resorption by simultaneously targeting osteoblasts, BMSCs, and osteoclasts. The bone-protective effects of Vildagliptin were further confirmed in a postmenopausal osteoporosis model. The clinical significance of this study lies in laying a theoretical foundation for bone protection therapy in type-2 diabetes patients with compromised bone conditions or postmenopausal osteoporosis.

METTL3-mediated m6A modification of SOX4 regulates osteoblast proliferation and differentiation via YTHDF3 recognition.

N6-methyladenosine (m6A), the most prevalent internal modification in mRNA, is related to the pathogenesis of osteoporosis (OP). Although methyltransferase Like-3 (METTL3), an m6A transferase, has been shown to mitigate OP progression, the mechanisms of METTL3-mediated m6A modification in osteoblast function remain unclear. Here, fluid shear stress (FSS) induced osteoblast proliferation and differentiation, resulting in elevated levels of METTL3 expression and m6A modification. Through Methylated RNA Immunoprecipitation Sequencing (MeRIP-seq) and Transcriptomic RNA Sequencing (RNA-seq), SRY (Sex Determining Region Y)-box 4 (SOX4) was screened as a target of METTL3, whose m6A-modified coding sequence (CDS) regions exhibited binding affinity towards METTL3. Further functional experiments demonstrated that knockdown of METTL3 and SOX4 hampered osteogenesis, and METTL3 knockdown compromised SOX4 mRNA stability. Via RNA immunoprecipitation (RIP) assays, we further confirmed the direct interaction between METTL3 and SOX4. YTH N6-Methyladenosine RNA Binding Protein 3 (YTHDF3) was identified as the m6A reader responsible for modulating SOX4 mRNA and protein levels by affecting its degradation. Furthermore, in vivo experiments demonstrated that bone loss in an ovariectomized (OVX) mouse model was reversed through the overexpression of SOX4 mediated by adeno-associated virus serotype 2 (AAV2). In conclusion, our research demonstrates that METTL3-mediated m6A modification of SOX4 plays a crucial role in regulating osteoblast proliferation and differentiation through its recognition by YTHDF3. Our research confirms METTL3-m6A-SOX4-YTHDF3 as an essential axis and potential mechanism in OP.

Prevalence and Site of Concomitant Osteochondral Injuries in Patients With Acute Lateral Patellar Dislocation: A Systematic Review and Meta-analysis.

Background: Osteochondral injuries (OCIs) are common in patients with acute lateral patellar dislocation, which can produce both short- and long-;term adverse effects. However, the pattern of these injuries warrants further analysis, especially in relation to patient age. Purpose: To determine the overall prevalence of concomitant OCIs as well as the prevalence differences based on location and age after acute lateral patellar dislocations. Study Design: Systematic review; Level of evidence, 4. Methods: A comprehensive search of PubMed, Embase, Web of Science, and Cochrane Library was completed from inception to July 20, 2022. All articles reporting the prevalence of OCI were included. The sample characteristics such as age, study design, magnetic resonance imaging diagnostic data, and the number of patients with OCI were extracted. The Methodological Index for Non-Randomized Studies (MINORS) was used for quality assessment. The overall and per-;site injury rates were calculated, and the prevalence was stratified by age-;group (≤16 and >16 years) and compared. Results: The systematic review included 39 studies involving 3354 patients. MINORS scores were 11.94 ± 1.98 and 16 ± 3.46 in the noncomparative and comparative studies, respectively. The overall prevalence of bone bruises and OCI was 89.6% (95% CI, 77.4%-97.7%) and 48.8% (95% CI, 39.0%-58.7%), respectively. In both overall and >16-year-old patients, the lateral femoral condyle (LFC) was the most common site of bone bruise (90.5% [95% CI, 84.0%-95.6%] and 91.5% [95% CI, 84.3%-96.9%], respectively); however, the medial patellar bruise was more common in patients ≤16 years (89.2% [95% CI, 82.9%-94.4%]). Among the pooled sites of OCI, the medial patella accounted for the largest proportion (36.9% [95% CI, 28.0%-46.3%]). OCIs were more common in patients >16 years (52.6% [95% CI, 39.4%-65.6%]) than in patients ≤16 years (46.6% [95% CI, 33.2%-60.3%]). Conclusion: Bone bruises on the LFC were most prevalent overall and in patients >16 years, whereas bone bruises on the medial patella were more prevalent in patients ≤16 years. OCIs were frequently seen in patients >16 years, with the most common site being the medial patella.

Associations of the serum vitamin D with mortality in postmenopausal women.

PURPOSE: Current evidence on the association of serum vitamin D with mortality in postmenopausal women is limited and inconsistent. Therefore, the purpose of this study was to examine the relationship between serum vitamin D and mortality in postmenopausal women. METHODS: In this study, we used data from the NHANES (2001-2018) and conducted a multivariate Cox regression model to examine associations between serum vitamin D and all-cause mortality, cardiovascular mortality (CVD), and cancer mortality. RESULTS: In a median follow-up period of 8.3 years, 1905 deaths of all causes were reported, 601 were due to CVD, and 385 deaths were due to cancer. After multivariable adjustment, higher serum vitamin D levels were significantly associated with a reduced risk of death. Compared to participants with lower vitamin D levels (<25 nmol/L), those with higher vitamin D levels (≥75.0 nmol/L) had a lower risk of all-cause mortality (hazard ratio 0.60, 95 % confidence interval 0.49 to 0.74), a lower risk of cardiovascular mortality (0.51, 0.35 to 0.74), and a lower risk of cancer mortality (0.43, 0.28 to 0.67). Moreover, we observed an L-shaped dose-response relationship of serum vitamin D levels with all-cause mortality, and cancer mortality, with this inflexion point being 55.9 nmol/L, and 51.2 nmol/L, respectively. CONCLUSIONS: Higher concentrations of serum vitamin D substantially correlated with a reduction in mortality risk from all-cause, CVD, and cancer in postmenopausal women. These results imply that upholding adequate vitamin D levels may help prevent premature death in postmenopausal women.

Artificial Intelligence Aids Detection of Rotator Cuff Pathology: A Systematic Review.

PURPOSE: To determine the model performance of artificial intelligence (AI) in detecting rotator cuff pathology using different imaging modalities and to compare capability with physicians in clinical scenarios. METHODS: The review followed the PRISMA guidelines and was registered on PROSPERO. The criteria were as follows: 1) studies on the application of AI in detecting rotator cuff pathology using medical images, and 2) studies on smart devices for assisting in diagnosis were excluded. The following data were extracted and recorded: statistical characteristics, input features, AI algorithms used, sample sizes of training and testing sets, and model performance. The data extracted from the included studies were narratively reviewed. RESULTS: A total of 14 articles, comprising 23,119 patients, met the inclusion and exclusion criteria. The pooled mean age of the patients was 56.7 years, and the female rate was 56.1%. The area under the curve (AUC) of the algorithmic model to detect rotator cuff pathology from ultrasound images, MRI images, and radiographic series ranged from 0.789 to 0.950, 0.844 to 0.943, and 0.820 to 0.830, respectively. Notably, 1 of the studies reported that AI models based on ultrasound images demonstrated a diagnostic performance similar to that of radiologists. Another comparative study demonstrated that AI models using MRI images exhibited greater accuracy and specificity compared to orthopedic surgeons in the diagnosis of rotator cuff pathology, albeit not in sensitivity. CONCLUSIONS: The detection of rotator cuff pathology has been significantly aided by the exceptional performance of AI models. In particular, these models are equally adept as musculoskeletal radiologists in using ultrasound to diagnose rotator cuff pathology. Furthermore, AI models exhibit statistically superior levels of accuracy and specificity when using MRI to diagnose rotator cuff pathology, albeit with no marked difference in sensitivity, in comparison to orthopaedic surgeons. LEVEL OF EVIDENCE: Level III, systematic review of Level III studies.

A novel lncRNA GM15416 regulates osteoblast apoptosis and differentiation through the c-Fos/Fas axis and mitigates osteoporosis.

Osteoporosis (OP) is a common systemic bone disorder, and the programmed cell death of osteoblasts is closely linked to the development of osteoporosis. Previous studies have shown that c-fos can cause osteoblast apoptosis. Furthermore, it has been demonstrated that long non-coding RNA (lncRNA) plays a pervasive role in regulating the biology of osteoblasts. Nevertheless, the precise role and mechanism of long non-coding RNA (lncRNA) in relation to c-Fos at the transcriptional level in osteoblast cell death remain uncertain. Compared with normal osteoblasts, serum deprivation resulted in significant upregulation of the transcription factor c-Fos and apoptosis-related Fas proteins in osteoblasts. In addition, the expression of lncRNA GM15416 related to c-Fos was significantly increased. The results showed that overexpression of c-Fos leads to an increase in downstream Fas protein, which subsequently leads to osteoblast apoptosis and hinders osteogenesis. On the contrary, a decrease in lncRNA GM15416 expression leads to a decrease in c-Fos/Fas expression, which hinders osteoblast apoptosis and promotes osteogenesis. Our results suggest that lncRNA GM15416 exerts inhibitory effects on osteoblast apoptosis and acts as a preventive factor against osteoporosis. As a result, GM15416 emerges as an important lncRNA associated with osteoporosis and holds potential as a future therapeutic target.

Bone mineral density is associated with composite dietary antioxidant index among US adults: results from NHANES.

This cross-sectional study investigated the relationship between composite dietary antioxidant index (CDAI) and individual dietary antioxidant intakes, including vitamins A, C, and E, zinc, selenium, and carotenoids, and bone mineral density (BMD) in the US population aged 20 years older. We found a positive correlation between CDAI and femoral BMD. Moreover, higher intakes of vitamin C, vitamin E, selenium, zinc, and carotenoids were associated with higher femoral BMD. INTRODUCTION: While individual dietary antioxidants have shown beneficial effects on bone metabolism, the diverse and potentially interacting nature of dietary components may limit the accuracy of evaluating their impact on bone health. Thus, this study aims to investigate the association between CDAI and BMD. Additionally, we explore the relationship between the intake of individual components of the CDAI and BMD. METHODS: The CDAI is a novel index evaluating total dietary antioxidant intake, considering vitamins A, C, and E, zinc, selenium, and carotenoids. A cross-sectional analysis was conducted using data from participants aged ≥ 20 in the National Health and Nutrition Examination Survey (2005-2010, 2013-2014, and 2017-2018). We utilized multivariate linear regression models to examine the relationship between CDAI, individual dietary antioxidants, including vitamins A, C, and E, zinc, selenium, carotenoids, and femoral BMD. RESULTS: The final analysis included 10,584 participants with a mean age of 50.73 ± 16.65 years. After multivariate adjustment, the second to fourth quartiles of CDAI (- 2.00-0.04, 0.04-2.54, and 2.54-70.78) exhibited higher femoral BMD compared to the first quartile of CADI (- 7.34 to - 2.00). Multiple regression analysis revealed that higher intakes of vitamin C, vitamin E, selenium, zinc, and carotenoids were associated with higher femoral BMD. CONCLUSIONS: CDAI serves as a comprehensive tool for evaluating the overall antioxidant capacity of antioxidants in diets. Additionally, our study shows a positive correlation between CDAI and BMD, which indicates that the combined intake of dietary antioxidants may help reduce the risk of osteoporosis in adults.

The optimal tibial tunnel placement to maximize the graft bending angle in the transtibial posterior cruciate ligament reconstruction: a quantitative assessment in three-dimensional computed tomography model.

Background: The graft bending angle created by the graft and the tibial tunnel has inevitably occurred during the transtibial posterior cruciate ligament (PCL) reconstruction. However, few studies quantitively analyzed this angle. This study aimed to (I) explore the optimal tibial tunnel placement to maximize the graft bending angle in the PCL reconstruction; (II) reveal the effect of the tibial tunnel placement on the graft bending angle. Methods: This was an in-vitro surgical simulation study based on the three-dimensional (3D) computed tomography (CT). A total of 55 patients who took CT scanning for knee injuries were selected (April 2020 to January 2022) from the local hospital database for review. The 3D knee models were established on the Mimics software based on the knees' CT data. Using the Rhinoceros software to simulate the transtibial PCL reconstruction on the 3D CT knee model. The anteromedial and anterolateral tibial tunnel approaches were simulated with different tibial tunnel angle. The graft bending angle and tibial tunnel length (TTL) with different tibial tunnel angles were quantitively analyzed. Results: The graft bending angle in anterolateral approach with a 50° tibial tunnel angle was significantly greater than it in anteromedial approach with a 60° tibial tunnel angle (P<0.001). There was no difference of the graft bending angle between the anterolateral approach with a 40° tibial tunnel angle and the anteromedial approach with a 60° tibial tunnel angle (P>0.05). The graft bending angle showed a strong correlation with the tibial tunnel angle (for anteromedial approach: r=0.759, P<0.001; for anterolateral approach: r=0.702, P<0.001). The best-fit equation to calculate the graft bending angle based on the tibial tunnel angle was Y = 0.89*X + 59.05 in anteromedial tibial tunnel approach (r2=0.576), and was Y = 0.78*X + 80.21 anterolateral tibial tunnel approach (r2=0.493). Conclusions: The graft bending angle and TTL will significantly increase as the tibial tunnel angle becomes greater. Maximizing the tibial tunnel angle (50° tibial tunnel angle) in the anterolateral approach could provide the greatest graft bending angle in the PCL reconstruction. No matter how the tibial tunnel angle is changed in the anteromedial approach, using anterolateral approach might reduce the killer turn effect more effectively than using anteromedial approach.

A novel primary osteoporosis screening tool (POST) for adults aged 50 years and over.

PURPOSE: This study aimed to develop and validate a simple primary osteoporosis screening tool (POST) based on adults aged 50 years and older. METHODS: This study included participants aged ≥50 from the National Health and Nutrition Examination Survey. Osteoporosis was defined according to bone mineral density values. The POST was developed based on methods from previous studies. Moreover, we plotted the receiver operating characteristic curves to calculate the area under the curve (AUC) and determine the optimal cut-off value according to the weighted Youden index. In addition, we compared the performances in identifying individuals with osteoporosis between the POST and the Osteoporosis Self-assessment Tool (OST). Finally, we also assessed the performance of the POST in the Chinese population. RESULTS: Finally, a total of 6665 individuals were included in this study. The AUC values of the POST for identifying individuals with osteoporosis in the development cohort and the validation cohort were 0.81 (95% CI: 0.79-0.83) and 0.81 (95% CI: 0.77-0.84), respectively. Moreover, a POST-score ≥7 was determined as the threshold to identify individuals with osteoporosis, in which the sensitivity was greater than 90%. In addition, the POST showed significantly higher sensitivity than the OST. Finally, the POST showed an AUC of 0.75 (95% CI: 0.65-0.85) among 94 Chinese subjects aged ≥50 years old. CONCLUSIONS: POST is a convenient and effective tool for osteoporosis screening among adults aged 50 years and over, which might provide new methodological support for future osteoporosis screening.

The tibial tunnel drilling angles of 60° provided a lower ultimate load to failure on a single bundle posterior cruciate ligament graft using interference screw fixation compared to 30°/45°.

PURPOSE: To biomechanically compare the initial fixation strength of grafts among three tibial tunnel angles (30°/45°/60°) in transtibial posterior cruciate ligament (PCL) reconstruction. METHODS: A series of transtibial PCL reconstruction models were established with porcine tibias and bovine tendons. Specimens were randomly assigned to three groups according to the angles between the tibial tunnel and the perpendicular line of the tibial shaft: Group A (30°, n = 12), Group B (45°, n = 12), and Group C (60°, n = 12). The area of the tunnel entrance, the segmental bone mineral density (sBMD) of the graft fixation site of the tibia and the maximum insertion torque of the interference screw were measured. Finally, load to failure tests were carried out on the graft-screw-tibia constructs at the same rate. RESULTS: Ultimate load to failure in Group C (335.2 ± 107.5 N) was significantly lower than that in Group A (584.1 ± 127.9 N, P < 0.01) and Group B (521.9 ± 95.9 N, P < 0.01). There were no significant differences between biomechanical properties of Groups A and B (n.s.). The posterior part fractures of the tibial tunnel exit occurred in eight specimens of Group C. In addition, the ultimate load was proven to be related to insertion torque (rho = 0.7, P < 0.01), sBMD (rho = 0.7, P < 0.01), and the area of the tunnel entrance (rho =- 0.4, P = 0.01). CONCLUSION: The ultimate load to failure was significantly lower in tibial PCL interference screw fixation for tunnels drilled at 60° compared to 30°/45°. In addition, the ultimate load was significantly correlated with insertion torque, sBMD and the area of the tunnel entrance. Given that the load to failure of distal fixation may not be sufficient for early postoperative rehabilitation, a 60° tunnel should not be recommended to drill in tibia during PCL reconstruction.