A novel configuration for the fixation of intra-articular C2.3 distal humerus fractures with the potential for minimally invasive surgery: a biomechanical evaluation and finite element analysis.

BACKGROUND: Distal humerus fractures are a challenge to treat, and the current standard of care, open reduction internal fixation with a double-plate, has a high rate of complications. We proposed a novel internal fixation configuration, lateral intramedullary nail and medial plate (LINMP) and verified its rigidity through biomechanical tests and finite element analysis. METHODS: The study involved biomechanical testing of 30 synthetic humerus models to compare 2 different fixation systems for an AO 13C-2.3 type fracture. The orthogonal double-plate (ODP) group and the LINMP group were compared through biomechanical testing to measure stiffness and failure load fewer than 3 working conditions. Based on the results, we optimized the intramedullary nail by eliminating the holes at the distal end of the nail and incorporating a 2-hole external locking plate. The Finite element analysis was also conducted to further compare the modified LINMP configuration with the previous 2 fixation configurations. RESULTS: In biomechanical tests, the ODP group exhibited lower stiffness under bending and compression forces compared to the LINMP group, but higher stiffness and failure loads under torsion force. In finite element analysis, the modified LINMP reduces the maximum stress of the fixation structure without significantly reducing the stiffness under bending stress and axial compression conditions. In torsion stress conditions, the modified LINMP enhances both the maximum stress and the stiffness, although it remains marginally inferior to the ODP structure. CONCLUSION: Our study demonstrates that the innovative LINMP presents comparable or slightly superior concerning bending and axial loading compared to orthogonal double-plate osteosynthesis for distal humeral intra-articular fractures, which might become a minimally invasive option for these fractures.

Tailoring Ionic Liquid Chemical Structure for Enhanced Interfacial Engineering in Two-Step Perovskite Photovoltaics.

Ionic liquids (ILs) have emerged as versatile tools for interfacial engineering in perovskite photovoltaics. Their multifaceted application targets defect mitigation at SnO2 -perovskite interfaces, finely tuning energy level alignment, and enhancing charge transport, meanwhile suppressing non-radiative recombination. However, the diverse chemical structures of ILs present challenges in selecting suitable candidates for effective interfacial modification. This study adopted a systematic approach, manipulating IL chemical structures. Three ILs with distinct anions are introduced to modify perovskite/SnO2 interfaces to elevate the photovoltaic capabilities of perovskite devices. Specifically, ILs with different anions exhibited varied chemical interactions, leading to notable passivation effects, as confirmed by Density Functional Theory (DFT) calculation. A detailed analysis is also conducted on the relationship between the ILs' structure and regulation of energy level arrangement, work function, perovskite crystallization, interface stress, charge transfer, and device performance. By optimizing IL chemical structures and exploiting their multifunctional interface modification properties, the champion device achieved a PCE of 24.52% with attentional long-term stability. The study establishes a holistic link between IL structures and device performance, thereby promoting wider application of ILs in perovskite-based technologies.

Effects of cyclic fluid stress at different frequencies on behaviors of cells incubated on titanium alloy.

The orthopedic external fixation is always in dynamic mechanical environment with the somatic movement. We used a self-designed mini oscillator to simulate this condition by providing the reciprocating cyclic fluid stress, and observed the behavioral responses of fibroblasts implanted on titanium alloy plane to the stress at different frequencies, including 0.2 Hz, 0.6 Hz, and 1.0 Hz. We found that the cell angle, shape index and expression of vinculin were mostly biphasic-dependent with the increase of frequency, with peaks at 0.6 Hz. Whereas the cell area, expression of Col-I and α-SMA were mainly affected by the 1.0 Hz stress. Interestingly, 1.0 Hz stress also promoted Col-I expression of bone marrow mesenchymal stem cells (BMSCs), although it did not increase α-SMA. These results reveal that 0.6 Hz stress improves the alignment, polarity and adherence of fibroblasts on titanium alloy substrates, thus improving the sealing of implants; the 1.0 Hz force activates the differentiation of fibroblasts into myofibroblasts and increases collagen produced by stem cells, which probably cause the formation of fibrous capsules around implants.

[Effects of Different Preservation Methods on Mechanical Properties of Mouse Femur].

In order to establish the best procedure to store the femur samples from the biomechanical viewpoint,we compared the effects of different storage methods on the mechanical properties of mouse femurs.We obtained femurs surgically from twenty C57BL/6Jfemale mice,12 weeks old,and randomly divided them into 5groups,i.e.fresh control group,4% paraformaldehyde fixation group,4℃storage group,-20℃storage group and-80℃storage group,respectively,with five mice in each group.For the three low-temperature storage groups,each group was stored for 1week,2months,6months at their respective temperatures.After rewarming,three-point bending test was performed to test the load and deflection changes.The results showed that both the elastic modulus and deflection decreased significantly in the 4% paraformaldehyde group.The maximum load and elastic modulus of the samples in the 4 ℃ group after one week storage was significantly reduced;The mechanical properties were close to the fresh control group in the-20℃ group stored for 2months but the maximum load was also reduced after 6months.However,mechanical properties,such as elastic load,maximum load and elastic modulus,were not changed obviously in the-80 ℃ storage group.Accordingly,-80 ℃ cryopreservation had little influence on the mechanical properties of bone tissues,which proved that the temperature-80 ℃is a suitable one for long-term preservation.

Implantation of customized 3-D printed titanium prosthesis in limb salvage surgery: a case series and review of the literature.

BACKGROUND: Although modular prosthesis is commercially available to meet requirements in most limb salvage surgeries, customized prosthesis is still needed. In contrast to traditional complicated procedures, rapid prototyping (RP) technique can directly manufacture customized titanium prosthesis. The objectives of this study were to describe the workflow of this technique and show the follow-up results of patients. METHODS: Three patients with clavicle Ewing's sarcoma (ES), scapular ES, and pelvic chondrosarcoma (CS) were scanned by computer tomography (CT). The images were segmented and reconstructed for preoperative planning and prosthesis design. Then, the data of prosthesis were imported into an electron beam melting system to manufacture implants. These three patients received prosthesis implantation after tumor excision. They were followed up to evaluate survival rate, functional outcome, and complications. RESULTS: All patients were alive with no evidence of disease. The Musculoskeletal Tumor Society (MSTS) scores were 93, 73, and 90 % for patients with clavicle ES, scapular ES, and pelvic CS, respectively. No surgical complications including limb length discrepancy, screw loosening, and implant breakage were observed in current study. CONCLUSIONS: Electron beam melting (EBM) is a useful method to directly manufacture customized titanium prostheses. It might improve the effectiveness of limb salvage surgery for sarcomas in unusual sites.

Three-dimensional virtual bone bank system for selecting massive bone allograft in orthopaedic oncology.

PURPOSE: Although structural bone allografts have been used for years to treat large defects caused by tumour or trauma, selecting the most appropriate allograft is still challenging. The objectives of this study were to: (1) describe the establishment of a visual bone bank system and workflow of allograft selection, and (2) show mid-term follow-up results of patients after allograft implantation. METHODS: Allografts were scanned and stored in Digital Imaging and Communications in Medicine (DICOM) files. Then, image segmentation was conducted and 3D model reconstructed to establish a visual bone bank system. Based on the volume registration method, allografts were selected after a careful matching process. From November 2010 to June 2013, with the help of the Computer-assisted Orthopaedic Surgery (CAOS) navigation system, the allografts were implanted in 14 patients to fill defects after tumour resection. RESULTS: By combining the virtual bone bank and CAOS, selection time was reduced and matching accuracy was increased. After 27.5 months of follow-up, the mean Musculoskeletal Tumor Society (MSTS) 93 functional score was 25.7 ± 1.1 points. Except for two patients with pulmonary metastases, 12 patents were alive without evidence of disease at the time this report was written. CONCLUSIONS: The virtual bone bank system was helpful for allograft selection, tumour excision and bone reconstruction, thereby improving the safety and effectiveness of limb-salvage surgery.

Salvianolic acid B attenuates spinal cord ischemia-reperfusion-induced neuronal injury and oxidative stress by activating the extracellular signal-regulated kinase pathway in rats.

BACKGROUND: Salvianolic acid B (SalB), the main bioactive compound isolated from the traditional Chinese medicinal herb broad Radix Salviae Miltiorrhizae exerts a spectrum of pharmacologic activities. We investigated the effects of SalB treatment in a rat model of spinal cord ischemia and reperfusion (I/R) injury and the underlying mechanism. MATERIALS AND METHODS: SalB was administered at 1, 10, or 50 mg/kg after spinal cord ischemia. The potential protective effects on spinal cord injury were determined by spinal cord edema, infarct volume, and motor function assessment of the hind limbs. RESULTS: SalB treatment significantly decreased spinal cord edema and infarct volume and preserved motor function of the hind limbs in a dose-dependent manner. SalB administration ameliorated the generation of oxidative products and preserved antioxidant defense activities in the injured spinal cord at both 4 and 24 h after I/R injury. Moreover, SalB prolonged the I/R injury-induced activation of extracellular signal-regulated kinase (ERK), and blocking ERK activation with PD98059 partially prevented the neuroprotective effects of SalB. CONCLUSIONS: These findings demonstrate the neuroprotective effects of SalB in a spinal cord I/R injury model and suggest that SalB-induced neuroprotection was mediated by ERK activation.

Precise resection and biological reconstruction under navigation guidance for young patients with juxta-articular bone sarcoma in lower extremity: preliminary report.

BACKGROUND: It is a challenge to perform a joint-preserving resection for young patients with juxta-articular bone sarcomas. We determined whether osteotomy under image-guided navigation make joint-saving resection possible for juxta-articular lesions while adhering oncological principles. METHODS: Between June 2008 and July 2010, joint-preserving limb salvage surgeries were performed on 9 patients with juxta-articular bone sarcomas under navigation guidance. Computed tomography/magnetic resonance imaging fusion images were used for real-time navigation. Eight lesions located around the knee and 1 in hip. Six tumors extend to and 3 beyond the epiphyseal line. Planned osteotomy under image-guided navigation was employed for achieving clear surgical margin while maximizing host tissue preservation. All tumors were en bloc removed and intercalary defect were reconstructed by combination of allograft with vascularized fibula graft. All specimens were examined for resection margin. Patients were followed up for an average of 25.2 months for evaluating of functional and oncology outcomes. RESULTS: Entire joint were preserved in 6 patients and part of joint were saved in another 3 patients. The mean registration error for navigation was 0.40 mm (range, 0.31 to 0.62 mm). Clear surgical margin was obtained in all specimens. The average closest distance between the osteotomy line and tumor edge was 9.6 mm (range, 6 to 14 mm). Entire joint cartilage was preserved in 6 patients and portion of joint were saved in 3 patients (2 in proximal tibia, 1 in distal femur). No patient experienced local recurrence. Two patients developed lung metastasis. One died of disease and the other underwent metastasectomy and had no evidence of disease at the most recent follow-up. All reconstruction was in situ with the Musculoskeletal Tumor Society average score of 26.7 at final follow-up. CONCLUSIONS: With careful patient selection, image navigation-assisted surgery made it possible to resect the bone exactly as planned in length and orientation in the magnetic resonance imaging image, yielding a clear margin and preserving the entire or part of the articular cartilage in joint-sparing limb salvage procedures for treating skeletally immature patients with juxta-articular bone sarcomas. LEVEL OF EVIDENCE: Level IV--therapeutic study.

ZIP4 upregulation aggravates nucleus pulposus cell degradation by promoting inflammation and oxidative stress by mediating the HDAC4-FoxO3a axis.

BACKGROUND: Extracellular matrix metabolism dysregulation in nucleus pulposus (NP) cells represents a crucial pathophysiological feature of intervertebral disc degeneration (IDD). Our study elucidates the role and mechanism of Testis expressed 11 (TEX11, also called ZIP4) extracellular matrix degradation in the NP. MATERIALS AND METHODS: Interleukin-1ß (IL-1ß) and H2O2 were used to treat NP cells to establish an IDD cell model. Normal NP tissues and NP tissues from IDD patients were harvested. ZIP4 mRNA and protein profiles in NP cells and tissues were examined. Enzyme-linked immunosorbent assay (ELISA) confirmed the profiles of TNF-α, IL-6, MDA, and SOD in NP cells. The alterations of reactive oxygen species (ROS), lactate dehydrogenase (LDH), COX2, iNOS, MMP-3, MMP-13, collagen II, aggrecan, FoxO3a, histone deacetylase 4 (HDAC4), Sirt1 and NF-κB levels in NP cells were determined using different assays. RESULTS: The ZIP4 profile increased in the NP tissues of IDD patients and IL-1ß- or H2O2-treated NP cells. ZIP4 upregulation bolstered inflammation and oxidative stress in NP cells undergoing IL-1ß treatment and exacerbated their extracellular matrix degradation, whereas ZIP4 knockdown produced the opposite outcome. Mechanistically, ZIP4 upregulated HDAC4 and enhanced NF-κB phosphorylation while repressing Sirt1 and FoxO3a phosphorylation levels. HDAC4 knockdown or Sirt1 promotion attenuated the effects mediated by ZIP4 overexpression in NP cells. CONCLUSIONS: ZIP4 upregulation aggravates the extracellular matrix (ECM) degradation of NP cells by mediating inflammation and oxidative stress through the HDAC4-FoxO3a axis.

Application of image recognition-based tracker-less augmented reality navigation system in a series of sawbone trials.

BACKGROUND: This study introduced an Augmented Reality (AR) navigation system to address limitations in conventional high tibial osteotomy (HTO). The objective was to enhance precision and efficiency in HTO procedures, overcoming challenges such as inconsistent postoperative alignment and potential neurovascular damage. METHODS: The AR-MR (Mixed Reality) navigation system, comprising HoloLens, Unity Engine, and Vuforia software, was employed for pre-clinical trials using tibial sawbone models. CT images generated 3D anatomical models, projected via HoloLens, allowing surgeons to interact through intuitive hand gestures. The critical procedure of target tracking, essential for aligning virtual and real objects, was facilitated by Vuforia's feature detection algorithm. RESULTS: In trials, the AR-MR system demonstrated significant reductions in both preoperative planning and intraoperative times compared to conventional navigation and metal 3D-printed surgical guides. The AR system, while exhibiting lower accuracy, exhibited efficiency, making it a promising option for HTO procedures. The preoperative planning time for the AR system was notably shorter (4 min) compared to conventional navigation (30.5 min) and metal guides (75.5 min). Intraoperative time for AR lasted 8.5 min, considerably faster than that of conventional navigation (31.5 min) and metal guides (10.5 min). CONCLUSIONS: The AR navigation system presents a transformative approach to HTO, offering a trade-off between accuracy and efficiency. Ongoing improvements, such as the incorporation of two-stage registration and pointing devices, could further enhance precision. While the system may be less accurate, its efficiency renders it a potential breakthrough in orthopedic surgery, particularly for reducing unnecessary harm and streamlining surgical procedures.

Use of patient-specific templates in hip resurfacing arthroplasty: experience from sixteen cases.

PURPOSE: Hip resurfacing arthroplasty (HRA) is a technically demanding operation, requiring both accuracy and precision in placement of the acetabular and femoral components. Malalignment of the component can lead to notching and possible femoral neck fractures. We used specific templates created using a rapid prototyping machine based on the patients' anatomy, to aid in accurate intraoperative pin placement. METHODS: A 3D model of the hip was reconstructed using spiral computed tomography (CT) data by Amira 3.1 software in 16 patients in whom HRA was planned for hip osteoarthritis (OA). All of the patients in the study had normal contralateral hips. The rotational centre of femoral head on the normal side was superimposed using Imageware12.0 software to determine the centre of the femoral head on the contralateral side. The data was then used to produce patient-specific templates using a rapid prototyping technique. These templates were designed according to the anatomical features of femoral head surface, the rotation centre and the planned prosthesis shaft angle. The orientation of the prosthesis was determined by matching the model to the femoral head surface during the operation. In addition, a control group of 18 patients with OA was operated upon by the conventional method. RESULTS: The mean prosthesis stem shaft angle (SSA), as determined from postoperative imaging, was 138.68 ± 8.85° for the locating template group, and (118.9 ± 12.8) for the conventional group. CONCLUSIONS: The locating template designed and constructed preoperatively can provide precise and dependable location for hip resurfacing femoral components during arthroplasty and ensure the valgus stem placement necessary for optimal outcomes.

[Establishment of Schatzker classification digital models of tibial plateau fractures and its application on virtual surgery].

OBJECTIVE: To explore the establishment of Schatzker classification digital model of tibial plateau fractures and its application in virtual surgery. METHODS: Proximal tibial of one healthy male volunteer was examined with 64-slice spiral computed tomography (CT). The data were processed by software Mimics 10.01 and a model of proximal tibia was reconstructed. According to the Schatzker classification criteria of tibial plateau fractures, each type of fracture model was simulated.Screen-captures of fracture model were saved from different directions.Each type of fracture model was exported as video mode.Fracture model was imported into FreeForm modeling system.With a force feedback device, a surgeon could conduct virtual fracture operation simulation.Utilizing the GHOST of FreeForm modeling system, the software of virtual cutting, fracture reduction and fixation was developed.With a force feedback device PHANTOM, a surgeon could manipulate virtual surgical instruments and fracture classification model and simulate surgical actions such as assembly of surgical instruments, drilling, implantation of screw, reduction of fracture, bone grafting and fracture fixation, etc. RESULTS: The digital fracture model was intuitive, three-dimensional and realistic and it had excellent visual effect.Fracture could be observed and charted from optional direction and angle.Fracture model could rotate 360 ° in the corresponding video mode. The virtual surgical environment had a strong sense of reality, immersion and telepresence as well as good interaction and force feedback function in the FreeForm modeling system. The user could make the corresponding decisions about surgical method and choice of internal fixation according to the specific type of tibial plateau fracture as well as repeated operational practice in virtual surgery system. CONCLUSION: The digital fracture model of Schatzker classification is intuitive, three-dimensional, realistic and dynamic. The virtual surgery systems of Schatzker classifications make the virtual surgery training more normalized, programmed and standardized.In addition, virtual surgery system can serve as a new tool for preoperative planning and surgeon-patient interactions.

[Three-dimensional flow perfusion culture enhances proliferation of human fetal osteoblasts in large scaffold with controlled architecture].

OBJECTIVE: To demonstrate the feasibility and benefits of custom designed perfusion bioreactor in conjunction with well-defined three-dimensional (3D) environment for enhanced proliferation and homogeneous distribution of human fetal osteoblasts in large scaffold in vitro. METHODS: Large-scale ß-tricalcium phosphate (ß-TCP) scaffolds with tightly controlled architectures were fabricated. And a custom designed perfusion bioreactor was developed. Human fetal osteoblasts were seeded onto the scaffolds, cultured for up to 16 days in static or flow perfusion conditions. At Days 4, 8 & 16 post-incubation, the proliferation and distribution of osteoblasts were determined by daily D-glucose consumption, cell viability (methyl thiazolyl tetrazolium (MTT) assay), histological evaluation and scanning electron microcopy (SEM). Sphere like structures observed in the SEM images were assessed by energy dispersive X-ray (EDX) analysis. RESULTS: In both static and perfusion cultures, the daily D-glucose consumption increased with prolonged time. The daily D-glucose consumption was significantly higher in the perfusion culture than that in static culture (P < 0.05). The increased cell viability with time during the culture was similar to the daily D-glucose consumption under both conditions. There was much greater cell viability under flow perfusion culture compared to static culture (P < 0.05). Flow perfused constructs demonstrated improved cell proliferation and a homogeneous layer composed of cells and extracellular matrix in channels throughout the whole scaffold. However, the cells were biased to periphery in scaffolds culture statically. Sphere like structures present in the matrix were identified as calcium phosphate nodules via EDX analysis. CONCLUSIONS: Flow perfusion culture plus well-defined 3D interconnected channel environments enhances the proliferation and improve the distribution of human fetal osteoblasts in large scaffolds. Scaffolds with controlled architecture may be a potential tool of studying the fluid flow configuration and cell behavior inside scaffold in details. And human fetal osteoblasts can be used as a cell source in large bone graft research.

[Experimental study of repairing femoral bone defects with nHA/RHLC/PLA scaffold composite with endothelial cells and osteoblasts in canines].

OBJECTIVE: To explore whether a tissue-engineered construct composed of autogenous endothelial cells, osteoblasts and a new bioresorbable nano-hydroxyapatite/recombinant human-like collagen/polylactic acid (nHA/RHLC/PLA) would enhance bone regeneration and repair femoral head defects in canine models. METHODS: The bone marrow stem cells (BMSCs) were isolated from bone marrow of canine ilium and cultured in Dulbecco's modified eagle medium:nutrient mixture F-12 culture media for 1 week and the second-generation BMSCs were further induced by osteogenic medium (1×10(-8) mol/L dexamethasone, 10 mmol/L B-sodium glycerophosphate and 50 µg/ml vitamin C) and by endothelial cell grow medium (vascular endothelial growth factor and basic fibroblast growth factor) for 14 days in vitro. Thus BMSCs were induced into ECs and OBs. After the second passage, cells were digested and collected.And cell density was adjusted to 1.0×10(6)/ml.The cells and nHA/RHLC/PLA scaffold were co-cultured for 2-4 hours then nHA/RHLC/PLA scaffold composites prepared. Cavity defects of 8 mm in diameter and 10 mm in height were made in femoral heads.The nHA/RHLC/PLA scaffold composited with ECs and osteoblasts (OBs) (group A) and composited with OBs (group B) were inserted into different defects while cell-free nHA/RHLC/PLA scaffold served as controls (group C). New bone formation and defect repair were evaluated at 3 and 6 months by radiographic examination, histology and bone histomorphometry. RESULTS: New bone formation was evident as early as 3 months in groups A, B and C.At 6 months, abundant bone tissue within defects was observed in group A. The control animals with cell-free scaffold showed less bone formation at both timepoints.The scaffold of nHA/RHLC/PLA was degraded and absorbed gradually with the formation of new bone tissues.Histology and bone histomorphometry further revealed significantly increased trabecular bones in group A compared with groups B and C at 6 months postimplantation (P < 0.01). CONCLUSION: More abundant new bone tissue may be found in the bone defect areas implanted with osteoblast-endotheliocyte composite than osteoblasts composite and scaffold materials only.ECs and osteoblasts derived from BMSC are ideal seed cells for repairing femoral head defects.

Combined Molybdenum Gelatine Methacrylate Injectable Nano-Hydrogel Effective Against Diabetic Bone Regeneration.

Introduction: Bone defects in diabetes mellitus (DM) remain a major challenge for clinical treatment. Fluctuating glucose levels in DM patients lead to excessive production of reactive oxygen species (ROS), which disrupt bone repair homeostasis. Bone filler materials have been widely used in the clinical treatment of DM-related bone defects, but overall they lack efficacy in improving the bone microenvironment and inducing osteogenesis. We utilized a gelatine methacrylate (GelMA) hydrogel with excellent biological properties in combination with molybdenum (Mo)-based polyoxometalate nanoclusters (POM) to scavenge ROS and promote osteoblast proliferation and osteogenic differentiation through the slow-release effect of POM, providing a feasible strategy for the application of biologically useful bone fillers in bone regeneration. Methods: We synthesized an injectable hydrogel by gelatine methacrylate (GelMA) and POM. The antioxidant capacity and biological properties of the synthesized GelMA/POM hydrogel were tested. Results: In vitro, studies showed that hydrogels can inhibit excessive reactive oxygen species (ROS) and reduce oxidative stress in cells through the beneficial effects of pH-sensitive POM. Osteogenic differentiation assays showed that GelMA/POM had good osteogenic properties with upregulated expression of osteogenic genes (BMP2, RUNX2, Osterix, ALP). Furthermore, RNA-sequencing revealed that activation of the PI3K/Akt signalling pathway in MC3T3-E1 cells with GelMA/POM may be a potential mechanism to promote osteogenesis. In an in vivo study, radiological and histological analyses showed enhanced bone regeneration in diabetic mice, after the application of GelMA/POM. Conclusion: In summary, GelMA/POM hydrogels can enhance bone regeneration by directly scavenging ROS and activating the PI3K/Akt signalling pathway.

Microgroove Cues Guiding Fibrogenesis of Stem Cells via Intracellular Force.

Groove patterns are widely used in material surface modifications. However, the independent role of ditches/ridges in regulating fibrosis of soft tissues is not well-understood, especially the lack of linkage evidence in vitro and in vivo. Herein, two kinds of combinational microgroove chips with the gradient ditch/ridge width were fabricated by photolithography technology, termed R and G groups, respectively. In group R, the ridge width was 1, 5, 10, and 30 µm, with a ditch width of 30 µm; in group G, the groove width was 5, 10, 20, and 30 µm, and the ridge width was 5 µm. The effect of microgrooves on the morphology, proliferation, and expression of fibrous markers of stem cells was systematically investigated in vitro. Moreover, thicknesses of fibrous capsules were evaluated after chips were implanted into the muscular pouches of rats for 5 months. The results show that microgrooves have almost no effect on cell proliferation but significantly modulate the morphology of cells and focal adhesions (FAs) in vitro, as well as fibrosis differentiation. In particular, the differentiation of stem cells is attenuated after the intracellular force caused by stress fibers and FAs is interfered by drugs, such as rotenone and blebbistatin. Histological analysis shows that patterns of high intracellular force can apparently stimulate soft tissue fibrosis in vivo. This study not only reveals the specific rules and mechanisms of ditch/ridge regulating stem cell behaviors but also offers insight into tailoring implant surface patterns to induce controlled soft tissue fibrosis.

[Targeted muscle reinnervation: a surgical technique of human-machine interface for intelligent prosthesis].

Objective: To review targeted muscle reinnervation (TMR) surgery for the construction of intelligent prosthetic human-machine interface, thus providing a new clinical intervention paradigm for the functional reconstruction of residual limbs in amputees. Methods: Extensively consulted relevant literature domestically and abroad and systematically expounded the surgical requirements of intelligent prosthetics, TMR operation plan, target population, prognosis, as well as the development and future of TMR. Results: TMR facilitates intuitive control of intelligent prostheses in amputees by reconstructing the "brain-spinal cord-peripheral nerve-skeletal muscle" neurotransmission pathway and increasing the surface electromyographic signals required for pattern recognition. TMR surgery for different purposes is suitable for different target populations. Conclusion: TMR surgery has been certified abroad as a transformative technology for improving prosthetic manipulation, and is expected to become a new clinical paradigm for 2 million amputees in China.

Corrigendum to 'Fabrication of a bio-instructive scaffold conferred with a favorable microenvironment allowing for superior implant osseointegration and accelerated in situ vascularized bone regeneration via type H vessel formation' [Bioactive Materials, Volume 9 (March 2022) Page 491-507].

[This corrects the article DOI: 10.1016/j.bioactmat.2021.07.030.].

Deep learning based ultrasonic visualization of distal humeral cartilage for image-guided therapy: a pilot validation study.

Background: Ultrasound is widely used for image-guided therapy (IGT) in many surgical fields, thanks to its various advantages, such as portability, lack of radiation and real-time imaging. This article presents the first attempt to utilize multiple deep learning algorithms in distal humeral cartilage segmentation for dynamic, volumetric ultrasound images employed in minimally invasive surgery. Methods: The dataset, consisting 5,321 ultrasound images were collected from 12 healthy volunteers. These images were randomly split into training and validation sets in an 8:2 ratio. Based on deep learning algorithms, 9 semantic segmentation networks were developed and trained using our dataset at Southern University of Science and Technology Hospital in September 2022. The performance of the networks was evaluated based on their segmenting accuracy and processing efficiency. Furthermore, these networks were implemented in an IGT system to assess their feasibility in 3-dimentional imaging precision. Results: In 2D segmentation, Medical Transformer (MedT) showed the highest accuracy result with a Dice score of 89.4%, however, the efficiency in processing images was relatively lower at 2.6 frames per second (FPS). In 3D imaging, the average root mean square (RMS) between ultrasound (US)-generated models based on the networks and magnetic resonance imaging (MRI)-generated models was no more than 1.12 mm. Conclusions: The findings of this study indicate the technological feasibility of a novel method for real-time visualization of distal humeral cartilage. The increased precision of ultrasound calibration and segmentation are both important approaches to improve the accuracy of 3D imaging.

Sensory nerves directly promote osteoclastogenesis by secreting peptidyl-prolyl cis-trans isomerase D (Cyp40).

Given afferent functions, sensory nerves have recently been found to exert efferent effects and directly alter organ physiology. Additionally, several studies have highlighted the indirect but crucial role of sensory nerves in the regulation of the physiological function of osteoclasts. Nonetheless, evidence regarding the direct sensory nerve efferent influence on osteoclasts is lacking. In the current study, we found that high levels of efferent signals were transported directly from the sensory nerves into osteoclasts. Furthermore, sensory hypersensitivity significantly increased osteoclastic bone resorption, and sensory neurons (SNs) directly promoted osteoclastogenesis in an in vitro coculture system. Moreover, we screened a novel neuropeptide, Cyp40, using an isobaric tag for relative and absolute quantitation (iTRAQ). We observed that Cyp40 is the efferent signal from sensory nerves, and it plays a critical role in osteoclastogenesis via the aryl hydrocarbon receptor (AhR)-Ras/Raf-p-Erk-NFATc1 pathway. These findings revealed a novel mechanism regarding the influence of sensory nerves on bone regulation, i.e., a direct promoting effect on osteoclastogenesis by the secretion of Cyp40. Therefore, inhibiting Cyp40 could serve as a strategy to improve bone quality in osteoporosis and promote bone repair after bone injury.