[Finite element analysis of anatomic plate fixation for proximal clavicular fractures].

OBJECTIVE: To explore establishment and finite element analysis of personalized proximal clavicular anatomical plate screw fixation model. METHODS: A 40-year-old male healthy volunteer was selected and the finite element analysis modules of 3D reconstruction software Mimics 15.01, Hypermesh 2019 and Abaqus 2020 were used. The finite element model of anatomic plate at the proximal clavicle was established, and a vertical load of 250 N was applied to the distal end of long axis of clavicle about 15 mm, then the overall structure, plate and screw displacement cloud image, Mises stress distribution were observed. RESULTS: The displacement distribution of the overall structure shows the maximum displacement was distributed on the distal clavicle. Under the four conditions of normal upper limb weight, longitudinal clavicle fracture, oblique fracture and shoulder impact violence during fall, longitudinal clavicle fracture and oblique fracture, the maximum displacement were 1.04 mm, 1.03 mm, 1.35 mm and 1.33 mm, respectively. The displacement cloud map of titanium alloy steel plate showed the largest displacement was distributed near the distal clavicular bone, and the maximum displacement were 0.89 mm, 0.88 mm, 1.10 mm and 1.09 mm, respectively. The displacement cloud map of titanium alloy screw showed the largest displacement was distributed at the root of the distal screw, and the maximum displacement were 0.88 mm, 0.87 mm, 1.08 mm and 1.06 mm, respectively. Mises stress distribution showed the maximum stress was mainly distributed on titanium alloy plates and screws, and the stress on the clavicle was very small. Mises stress distribution cloud showed the maximum Mises stress was distributed at the second row of screw holes near the clavicle, and the maximum Mises stress were 673.1, 678.1, 648.5, 654.4 MPa, respectively. The maximum stresses of titanium alloy screws were 414.5, 417.4, 415.8 and 419.7 MPa, respectively. CONCLUSION: The biomechanical changes of personalized proximal clavicular anatomical plates are demonstrated by using 3D finite element method to provide biomechanical data for personalized proximal clavicular anatomical plates.

Dynamic response of sandwich functionally graded nanoplate under thermal environments and elastic foundations using dynamic stiffness method.

The present paper introduces the development of dynamic stiffness method for analyzing small-scale sandwich functionally graded nanoplates resting on elastic foundation in thermal environments. The mathematical formulation is based on classical plate theory in conjunction with nonlocal elasticity theory. The governing equation is derived using Hamilton's principle. The dynamic stiffness matrix is obtained through the application of the Levy displacement approach and assembled to form the global stiffness matrix. The final matrix is solved for natural frequency of the plates using the Wittrick-Williams algorithm. The proposed methodology is validated against existing literature, demonstrating a strong agreement. Various parametric studies explore the effects of thermal environments, volume fraction index, sandwich configurations, elastic foundation characteristics, nonlocal parameter and boundary conditions. The results show the versatility of the proposed approach in addressing small scaled complex engineering structures. This research significantly contributes to the understanding and analysis of sandwich functionally graded nanoplates, providing valuable insights for applications in aerospace, structural systems, sensors, actuators, and energy harvesting devices.

Self-perceived middle-distance race pace is faster in advanced footwear technology spikes.

BACKGROUND: Quantifying the potential benefits of advanced footwear technology (AFT) track shoes (i.e., "spikes") in middle-distance events is challenging, because repeated maximal effort trials (as in sprinting) or aerobic running economy trials (as in long-distance running) are not feasible. METHODS: We introduce a novel approach to assess the benefits of AFT spikes, consisting of a series of 200-m runs at self-perceived middle-distance race pace with 10 min recovery, and conduct 4 experiments to evaluate its validity, sensitivity, reproducibility, and utility. RESULTS: In Experiment 1, participants ran 1.2% slower in spikes with 200 g added mass vs. control spikes, which is exactly equal to the known effects of shoe mass on running performance. In Experiment 2, participants ran significantly faster in AFT prototype spikes vs. traditional spikes. In Experiment 3, we compared 2 other AFT prototype spikes against traditional spikes on 3 separate days. Group-level results were consistent across days, but our data indicates that at least 2 separate sessions are needed to evaluate individual responses. In Experiment 4, participants ran significantly faster in 2 AFT spike models vs. traditional spikes (2.1% and 1.6%). Speed was similar between a third AFT spike model and the traditional spikes. These speed results were mirrored by changes in step length as participants took significantly longer steps in the 2 faster AFT spike models (2.3% and 1.9%), while step length was similar between the other spikes. CONCLUSION: Our novel, interval-based approach is a valid and reliable method for quantifying differences between spikes at middle-distance running intensity.

Effects of Chronic Prenatal Alcohol Exposure on Nociceptive Responses to Mechanical and Thermal Stimuli in Rats.

The present study sought to investigate the effects of chronic prenatal alcohol exposure (PAE) on nociceptive responses to mechanical and thermal stimuli in rats. The Von Frey and Hot Plate tests were employed to assess the nociceptive responses of 10 control rats and 7 experimental rats whose mothers had been administered ethanol from day 5 to day 20 of gestation. In healthy animals, a decrease in pain sensitivity was observed between days 28 and 70, which was not observed in the experimental group. The findings also indicated that rats with PAE exhibited diminished sensitivity to nociceptive stimuli during the early postnatal period, as evidenced by a higher threshold response to mechanical stimuli at day 28 than in the control group. However, those observations did not apply to thermal stimuli. It appears that this may be a result of distinctiveness in neural pain pathways for particular stimuli at the receptor or ion channel level, while a disruption in the equilibrium between the sympathetic and parasympathetic nervous systems may be a contributing factor. The results of this study highlight a critical aspect of the harmful systemic effects of alcohol, while also underscoring the need for further research to elucidate the underlying mechanisms, including the role of the hypothalamic-pituitary-adrenal axis and the serotonergic system in modulating pain responses in individuals prenatally exposed to alcohol.

Special contoured pelvic brim reconstruction titanium plate combined with trans-plate buttress screws (quadrilateral screws) for acetabular fractures with quadrilateral plate involvement through the anterior ilioinguinal approach.

Background: Managing complicated acetabular fractures involving the quadrilateral plate (QLP) can be challenging for surgeons, especially when complicated by comminution and osteoporosis. Traditional implants do not provide sufficient fixed strength or a proper match. The new-type pre-contoured infrapectineal buttress plates may have drawbacks, such as inaccurate fitting on the medial surface of QLP and an inability to apply reversed compression force to resist medial displacement of femoral head. Therefore, the primary purpose of this study is to introduce a novel technique that utilizes a special contoured pelvic brim reconstruction titanium plate combined with quadrilateral screws to reduce and stabilize acetabular fractures involving the QLP through the ilioinguinal approach. Additionally, the secondary purpose is to evaluate both clinical effectiveness and radiological outcomes of this technique for QLP fractures. Methods: We conducted a retrospective analysis of prospectively collected data from 48 patients (31 males and 17 females) who suffered from acute displaced fractures of the QLP and were treated between January 2012 and December 2019 using a special contoured plate combined with quadrilateral screws. The patients' mean age was 47.56 ± 11.31 years (range: 19-73 years). Fracture patterns included 20 both-column fractures, 12 anterior column and posterior hemitransverse fractures, eight T-type fractures, five transverse fractures and three anterior column fractures with the QLP affected, all of which had femoral head protrusion. Immediate postoperative reduction quality was evaluated according to Matta's criteria. Final clinical functions were assessed during follow-up using the modified Merle d'Aubigné and Harris Hip scores (HHS). Results: The patients were followed up for an average of 48.36 ± 12.94 months (ranging from 24 to 84 months). The mean operative time was 246.08 ± 54.30 min (ranging from 178 to 397 min), and the average blood loss was 715.16 ± 263.84 ml (ranging from 400 to 2000ml). The radiological grading at postoperative stage showed anatomical reduction in 30 patients (62.50%), satisfactory reduction in 14 patients (29.17%), and poor reduction in four patients (8.33%). At the final follow-up, no re-protrusion of the femoral head was observed. In terms of functional outcome, the mean modified Merle d'Aubigné-Postel score was excellent in 26 patients (54.17%), good in 17 patients (35.42%), fair in four patients (8.33%), and poor in one patient (2.08%). The HHS was excellent in 23 patients (47.92%), good in 20 patients (41.67%), fair in four patients (8.33%), and poor in one patient (2.08%). The average HHS was 87.38 ± 7.86 (ranging from 52 to 98). Postoperative complications included lateral femoral cutaneous nerve injury in two patients, delayed wound healing and subsequent development of an inguinal hernia in one patient. Late complications were observed in two patients, with one case of heterotopic ossification and another case of post-traumatic osteoarthritis underwent hip arthroplasty within two years after surgery. Conclusion: Our results indicate that employing the contoured plate specifically designed for QLP injuries, in conjunction with quadrilateral screws through the ilioinguinal approach, can lead to positive outcomes in the treatment of displaced acetabular fractures involving the QLP. This straightforward and efficient technique offers a viable option for surgeons who are managing complex acetabular fractures.

Pre-operative virtual three-dimensional planning for proximal humerus fractures: A proof-of-concept study.

Purpose: To (1) evaluate surgeon agreement on plating features (position and screw length) in virtual 3D planning software, (2) describe outcomes (fracture reduction, plate position, malpositioning of calcar screws and screw lengths) of plate fixations planned with routine pre-operative assessment (2D- and 3D CT imaging) and those planned with dedicated virtual 3D software of the same proximal humerus fracture. Methods: Fourteen proximal humerus fractures were retrospectively reduced and fixed with virtual planning software by eight attending orthopaedic surgeons and compared to the true surgical fixation with post-operative computed tomography (CT) scans. Reduction differences were quantified using CT micromotion analysis. Results: Intraclass correlation for screw lengths was 0.97 (95% CI: 0.96-0.98) and 0.90 (95% CI: 0.79-0.96) for plate position. Mean difference in total fracture rotation of the head between the virtual and conventional group was 22.0°. Plate position in the virtual planning group was 3.2 mm more proximal. There were no differences in inferomedial quadrant calcar screw positioning and, apart from the superior posterior converging screw, no significant differences in screw lengths. Conclusion: Reproducibility on plate position and screw length with virtual planning software is adequate. Apart from fracture reduction, virtual planning yielded similar plate positions, screw malpositioning rates and lengths compared to routine pre-operative assessment.

Evaluation of three serological tests for the diagnosis of Brucella suis in dogs using Bayesian latent class analysis.

Brucella suis infection of dogs is an emerging issue worldwide requiring specific management to address zoonotic risks and animal welfare concerns. Diagnosis in dogs is routinely based on serological testing, but to date these tests have only been validated for use in production animal species and humans. This study aimed to assess the diagnostic performance of three commonly used serological tests in dogs. Canine sera (n = 989) were tested with the Rose Bengal rapid plate agglutination test (RBRPT), the complement fixation test (CFT) and a competitive ELISA (C-ELISA). Diagnostic test performance was evaluated using a three test, two population Bayesian latent class analysis accounting for conditional dependence between the three tests. Positive and negative predictive values (PPV, NPV) were calculated for a range of expected prevalence estimates for the individual tests and test combinations interpreted in series and parallel. The RBRPT showed the highest individual Se of 0.902 (95 % posterior credible interval [PCI] 0.759-0.978) and the CFT the highest individual diagnostic specificity (Sp) of 0.914 (95 % PCI 0.886-0.946). The C-ELISA had marginally the best overall diagnostic performance (Youden's index = 0.807). The CFT and the C-ELISA interpreted in parallel returned the highest combined Se and Sp (0.988 and 0.885, respectively). All tests returned NPVs of > 0.982 in 2-8 % prevalence settings. Series interpretation of the three-test combination as well as the two-test combinations of the RBRPT and the C-ELISA and the CFT and the C-ELISA produced a PPV of 0.502 when the estimated prevalence was 8 %. While all tests are suitable for the detection of B. suis antibodies in dogs, they should not be interpreted in isolation as their diagnostic value is dependent on the pre-test probability of the disease. As such they are useful tools for the diagnosis of B. suis in dogs when exposure, history and clinical presentation indicate a risk of brucellosis.

Comparative study of CAD/CAM reconstruction and miniplates for patient-specific fixation in LCL-type mandibular reconstruction.

Objective: Miniplates offer superior clinical handling and facilitate postoperative removal after mandibular reconstruction but unfavorable load distribution under high stress has been shown. This study aimed to compare the clinical outcome of patient-specific 3D-printed (PS-3D) titanium miniplate with reconstruction plate fixation in three-segmental LCL-type reconstructions for the first time. Methods: Patients undergoing three-segmental LCL-type mandibular reconstruction after malignant tumor resection between April 2017 and July 2023 were analyzed in a retrospective single-center study. Inclusion criteria were primary reconstruction using a fibula free flap and PS-3D titanium mini- or reconstruction plate fixation. Complication rates were recorded and analyzed within 6 months after surgery using the N - 1 Chi2- and unequal variance t-test. Results: 38 patients (10 females, 28 males; mean age 61.4 ± 7.6 years) met the inclusion criteria. In 14 patients (36.8%) miniplates were used in the anterior region. Rates of fixation failure, plate exposure, incomplete osseous union, wound infection, soft tissue, and overall complications did not differ significantly between the two plate systems. Conclusion: Complication rates did not differ significantly between PS-3D mini- and reconstruction plates in three-segmental LCL-type mandibular reconstructions. Given their advantages in clinical handling and postoperative removal, PS-3D miniplates can be a viable alternative also in larger mandibular reconstructions.

Dissociated urethral plate Onlay and standard Onlay urethroplasty for mid-distal hypospadias: A comparative study.

BACKGROUND: Urethral plate (UP) reserved Onlay urethroplasty is currently used widely in mid-distal hypospadias. However, for children with 15-30° residual curvature after degloving, only dorsal tunica albuginea plication is performed to correct penile ventral curvature (VC), and long-term follow-up showed a high recurrence rate of penile curvature. We developed a modified Onlay urethroplasty, which dissociates the UP and completely removes the tissue beneath the UP to fully correct penile curvature. Furthermore, we compared it with the standard Onlay urethroplasty to explore its rationality and feasibility. METHODS: We prospectively collected clinical data from 68 children with hypospadias who underwent standard or modified Onlay urethroplasty between September 2019 and June 2021, and evaluated the interim outcomes to identify the complications between the two groups. Additionally, we conducted histological examination of the tissue beneath the UP. RESULTS: A total of 32 patients underwent modified Onlay urethroplasty. Intraoperative curvature measurements showed that 37.5% (12/32) of the patients had completely straightened their penis after UP dissection and removal of the fibrous tissue beneath it. A total of 36 patients underwent standard Onlay urethroplasty. Totally, five fistulas each were reported in the first and second groups, and the complication rates were 15.6% and 13.9%, respectively (P > 0.05). The histological results showed that the tissue below the UP contains a large amount of collagen, mainly type I collagen. CONCLUSION: The dissociated UP Onlay urethroplasty can maximally remove factors limiting penis growth and completely correct penile curvature, without increasing the incidence of postoperative complications. Therefore, we recommend the application of the improved Onlay urethroplasty in children with mid-distal hypospadias.

EVL is not essential for cuticular plate and stereocilia development in mouse auditory hair cells.

In inner ear hair cells, the stereocilia are inserted into a dense F-actin-enriched meshwork named the cuticular plate, which provides support to the stereocilia. Enah/Vasp-like (EVL) was shown to localize at the cuticular plate, and evl knockdown leads to disrupted cuticular plate and disorganized stereocilia in Xenopus hair cells. In the present work, we show that Evl transcripts are specifically expressed in mouse hair cells, and EVL is localized to the cuticular plate. However, the cuticular plate and stereocilia are unaffected by Evl knockout, and auditory function is largely normal in Evl knockout mice. In conclusion, our present data suggest that EVL is not essential for cuticular plate and stereocilia development in mouse auditory hair cells.

Treatment of Pathological Proximal Femur Fracture in a Child With a Unicameral Bone Cyst: A Case Report.

Pathological proximal femur fractures secondary to unicameral bone cysts in the pediatric age group are uncommon. Despite the development of modern surgical treatments and implant choices, it is still debatable what the gold standard of treatment is for a unicameral bone cyst with pathological proximal femur fractures. We report a case of an eight-year-old child with a unicameral bone cyst and pathological fracture of the proximal right femur who was surgically treated with curettage, synthetic bone graft, and a pediatric hip plate as the choice of implant for osteosynthesis and stability.

Functional Outcome of Forearm Fractures Managed With Screw Nails vs. Dynamic Compression Plates: A Prospective Study.

Background Fractures of the forearm are very frequently encountered in day-to-day practice. These fractures have a bimodal age distribution. The forearm fractures are considered intra-articular and need absolute stability for adequate healing. The current treatment modalities include using intramedullary devices such as a square nail, locking intramedullary nail, or using a plate for fixation. In this study, we aim to determine the functional outcome of forearm fractures managed with a screw nail used as an intramedullary device as compared to a locking plate using the Grace-Eversmann criteria. Methodology Patients with forearm fractures were divided into two groups and treated with a screw nail and a dynamic compression plate. Patients were followed up at one month, three months, six months, and one year postoperatively and assessment was done using the Grace-Eversmann criteria. Results The study included a total of 30 subjects, ranging in age from 18 to 65. The majority of the patients had encountered a road traffic accident, following which they incurred a forearm fracture. Grace-Eversmann criteria was used for these patients at follow-up, and a total of 13 patients (86.6%) had good to excellent scores, which was similar when compared to the plate osteosynthesis group (86.6%). A significant difference in the amount of blood loss was noted in the screw nail osteosynthesis group as compared to the plate osteosynthesis group (p<0.05). Conclusions Though a dynamic compression plate is considered a standard method for fixation of the forearm fractures, the use of an intramedullary screw nail as a fixation device gives a similar result with excellent functional outcomes (Grace-Eversmann criteria). It also gives an added benefit of reduced blood loss and preservation of fracture biology.

Mathematical Modeling and Experimental Investigation of the Dynamic Response for an Annular Circular Plate Made of Glass/Polyester Composite Under Different Boundary Conditions.

Fiber-reinforced elastic laminated composites are extensively used in several domains owing to their high specific stiffness and strength and low specific density. Several studies were performed to ascertain the factors that affect the composite plates' dynamic properties. This study aims to derive a mathematical model for the dynamic response of the processed composite material in the form of an annular circular shape made of polyester/E-glass composite. The mathematical model was developed based on modified classical annular circular plate theory under dynamic loading, and all its formulas were solved using MATLAB 2023. The mathematical model was also verified with real experimental work involving the vibration test of the fabricated composite plate. The composite plate was processed by reinforcing the polyester matrix with E-glass fibers with a 50% volume fraction each by using the handy lay-up method. After fabrication, the composite plate was tested with a universal vibration tester, where the plate was impacted and released to free vibration, and the deflection was measured experimentally to compare it with the theoretical value calculated from the derived model. The plate was tested under two boundary conditions, namely, simply and built-in supported. The findings show good agreement between theoretical and experimental plate deflections at different angles, particularly at built-in supported boundary conditions. Also, a higher natural frequency was recorded at this condition compared to others, and this may be ascribed to the higher shear stresses involved due to large moments at the ends along with supporting. Meanwhile, the real experimental spectrum of the built-in condition was higher than others, as the sig view curve revealed.

Headless screw fixation of unstable ulnar styloid base fractures after distal radial fractures fixation.

Ulnar styloid fractures occur frequently concomitant with distal radial fractures. Although unstable distal radial fractures are mostly surgically treated, ulnar styloid fractures are often ignored. Unstable fractures at the base of the ulnar styloid may lead to persistent ulnar pain, due to distal radioulnar joint instability or ulnar styloid non-union. We retrospectively analyzed a single-surgeon cohort series of surgically treated distal radial fractures on how these concomitant ulnar styloid fractures were regarded: indications for surgery and surgical technique with headless screw fixation. 119 surgically treated distal radial fractures were assessed. 51 (42.8%) of the surgically treated distal radial fractures had a distal ulnar fracture, and more specifically 23 (19.3%) had a base fracture of the ulnar styloid. 9 (7.6%) of the wrists had a base fracture of the ulnar styloid which was considered after distal radial fracture fixation as persistently unstable, during distal radioulnar joint ballottement translation test. This fracture subtype was immediately treated with headless screw fixation, resulting in all cases in bony union, with a mean active pronation of 85°, a mean active supination of 80° and a clinical stable distal radioulnar joint, with minimal ulnar pain after 6 weeks (mean Visual Analogue Scale 1). After at least 12 months, persistent pain did not occur and mean QuickDASH was 2.5. According to this single-surgeon cohort series, headless screw fixation provides a reliable treatment for unstable base fractures of the ulnar styloid after distal radial fixation.

Factors influencing surgical outcomes of fixation with locking plate for three- and four-part proximal humerus fractures in patients aged 50 ​Years and older.

Background: Treating complex three- and four-part proximal humerus fractures, especially in the elderly, remains contentious, with internal fixation using locking plates and shoulder arthroplasty being primary options. Although proximal humerus locking plates are more commonly used than shoulder replacements, they have a high complication rate. Factors like low bone density, advanced age, multiple fragment fractures, and medial cortical support loss negatively impact treatment outcomes. This study evaluates the functional and radiographic outcomes of using locking plates for treating these fractures in patients aged 50 and older, and the factors influencing outcomes and complication rates at the Ho Chi Minh City Hospital for Trauma and Orthopedics. Method: A descriptive case series study was conducted on 58 patients aged 50 and older (15 males, 43 females) with three- and four-part proximal humerus fractures. These patients underwent open reduction and internal fixation with Locking - compression plate (LCP) periarticular proximal humerus plates at the Ho Chi Minh City Hospital for Traumatology and Orthopedics (HTO) from April 2020 to April 2022. The minimum postoperative follow-up period was 12 months. Results: The average age of the patients was 62.78 â€‹± â€‹7.73 years, with a mean follow-up of 26.24 â€‹± â€‹5.93 months. Among them, 41 had three-part fractures (70.68 â€‹%) and 17 had four-part fractures (29.32 â€‹%). At the final follow-up (≥12 months), the mean Constant-Murley score was 70.81 â€‹± â€‹9.15, and the mean QDASH score was 8.33 â€‹± â€‹2.77. Complications occurred in 6 cases (10.34 â€‹%). Complex fractures, such as four-part fractures with displacement greater than 2 â€‹mm, had lower Constant-Murley scores and higher QDASH scores (p â€‹< â€‹0.05). Age, gender, bone density by deltoid tuberosity index (DTI), bone grafting, and rotator cuff sutures showed similar trends, but the differences were not statistically significant. Conclusion: Open reduction and internal fixation (ORIF) provides good bone healing and functional outcomes for three- and four-part proximal humerus fractures. Factors such as age, gender, bone density, bone grafting, and rotator cuff sutures do not significantly affect outcomes. Therefore, osteoporosis should not be a contraindication for ORIF with locking plates in these cases. Complex fractures, however, often lead to poorer outcomes and higher complication rates post-surgery.

The G protein-coupled receptor ADGRG6 maintains mouse growth plate homeostasis through IHH Signaling.

The cartilage growth plate is essential for maintaining skeletal growth; however, the mechanisms governing postnatal growth plate homeostasis are still poorly understood. Using approaches of molecular mouse genetics and spatial transcriptomics applied to formalin-fixed, paraffin-embedded (FFPE) tissues, we show that ADGRG6/GPR126, a cartilage-enriched adhesion G protein-coupled receptor (GPCR), is essential for maintaining slow-cycling resting zone cells, appropriate chondrocyte proliferation and differentiation, and growth plate homeostasis in mice. Constitutive ablation of Adgrg6 in osteochondral progenitor cells with Col2a1Cre leads to a shortened resting zone, formation of cell clusters within the proliferative zone, and an elongated hypertrophic growth plate, marked by limited expression of PTHrP but increased IHH signaling throughout the growth plate. Attenuation of Smoothened (SMO)-dependent hedgehog signaling restored the Adgrg6 deficiency-induced expansion of hypertrophic chondrocytes, confirming that IHH signaling can promote chondrocyte hypertrophy in a PTHrP-independent manner. In contrast, postnatal ablation of Adgrg6 in mature chondrocytes with AcanCreERT2, induced after the formation of the resting zone, does not affect PTHrP expression but causes an overall reduction of growth plate thickness marked by increased cell death specifically in the resting zone cells and a general reduction of chondrocyte proliferation and differentiation. Spatial transcriptomics reveals that ADGRG6 is essential for maintaining chondrocyte homeostasis by regulating osteogenic and catabolic genes in all the zones of the postnatal growth plates, potentially through positive regulation of SOX9 expression. Our findings elucidate the essential role of a cartilage-enriched adhesion GPCR in regulating cell proliferation and hypertrophic differentiation by regulation of PTHrP/IHH signaling, maintenance of slow-cycle resting zone chondrocytes, and safeguarding chondrocyte homeostasis in postnatal mouse growth plates.

The cartilage growth plate is an essential structure for skeletal growth, however, the mechanisms that govern growth plate homeostasis are still poorly understood. In this study, we showed that an adhesion G protein-coupled receptor (GPCR) named ADGRG6 plays an essential role in maintaining the slow-cycling cells in the resting zone of the growth plate and directing appropriate proliferation and differentiation of the growth plate chondrocytes. Using a technique called spatial transcriptomics, we compared the gene expression profiles in control and Adgrg6 mutant growth plates and found that ADGRG6 prevents premature hypertrophic differentiation of the growth plate chondrocytes by negatively regulating Indian Hedgehog (IHH) signaling. In summary, our findings highlighted the essential role of a cartilage-enriched GPCR in maintaining growth plate homeostasis through IHH signaling.

Retinoic acid, an essential component of the roof plate organizer, promotes the spatio-temporal segregation of dorsal neural fates.

Dorsal neural tube-derived retinoic acid promotes the end of neural crest production and transition into a definitive roof plate. Here we analyze how this impacts the segregation of central and peripheral lineages, a process essential for tissue patterning and function. Localized in-ovo inhibition in quail embryos of retinoic acid activity followed by single cell transcriptomics unraveled a comprehensive list of differentially expressed genes relevant to these processes. Importantly, progenitors co-expressed neural crest, roof plate and dI1 interneuron markers indicating a failure in proper lineage segregation. Furthermore, separation between roof plate and dI1 interneurons is mediated by Notch activity downstream of retinoic acid, highlighting their critical role in establishing the roof plate-dI1 boundary. Within the peripheral branch, where absence of retinoic acid resulted in neural crest production and emigration extending into the roof plate stage, sensory progenitors failed to separate from melanocytes leading to formation of a common glia-melanocyte cell with aberrant migratory patterns. Together, the implementation of scRNA sequencing facilitated the discovery and characterization of a molecular mechanism responsible for the segregation of dorsal neural fates during development.

Slipped capital femoral epiphysis: emphasis on early recognition and potential pitfalls.

Slipped capital femoral epiphysis is a shearing injury through the growth plate of the proximal femur and is the most common hip disorder in adolescence. Delays in diagnosis persist across practice settings despite ongoing innovations in imaging. Recent insights into pathomechanics highlight the importance of femoral head surface morphology and rotational microinstability centered at the epiphyseal tubercle in causing early physeal changes, which can be detected on imaging prior to frank slip. Scrutiny of physeal morphology and comparison to the contralateral hip is critical at all stages of disease progression, and improper technique may result in undue diagnostic delay. Selective use of cross-sectional imaging can be helpful for troubleshooting equivocal early slips and can inform operative technique and adjuvant therapy candidacy in more severe cases. This review provides a comprehensive approach to imaging suspected slipped capital femoral epiphysis, with an emphasis on early detection and potential pitfalls.

Fracture-Related Infection of a Distal Femur Open Fracture Treated With a Supracutaneous Locking Plate.

Fracture-related infection (FRI) is a challenging complication in open fractures. It can cause major disability to patients and a burden to the public health sector. A multidisciplinary approach is required to eradicate infection and improve the quality of life for patients. We present a case of an FRI in an open fracture of the distal femur treated using a supracutaneous locking plate, which is an uncommon technique. This technique yields excellent outcomes in controlling local infection and providing satisfactory stability, especially for a peri-articular distal femur fracture with FRI. Therefore, supracutaneous plating using a locking plate can be considered an alternative option to conventional external fixations in managing FRIs.