Vitrification cryopreservation of ligaments based on zwitterionic betaine

Ligament cryopreservation enables a prolonged shelf life of allogeneic ligament grafts,which is fundamentally important to ligament reconstruction.However,conventional cryopreservation techniques fail to eliminate the damage caused by ice crystal growth and the toxicity of cryopreservation agents(CPAs).Here,we report a novel CPA vitrification formulation primarily composed of betaine for ligament cryopreservation.Comprehensive optimization was conducted on the methods for vitrification and rewarming,as well as the loading and unloading conditions,based on the critical cooling rate(CCR),critical warming rate(CWR),and permeation properties of the CPA.Using biomechanical and histological level tests,we demonstrate the superior performance of our method in ligament cryopreservation.After 30 days of vitrification cryopreservation,parameters such as the Young's modulus,tensile stress,denaturation temperature,and glycosaminoglycans content of the ligament remained essentially unchanged.This work pioneers the application of ice-free cryopreservation for ligament and holds great potential for improving the long-term storage of ligament,providing valuable insights for future cryopreservation technique development.

Anatomy of the lateral ligaments of the rectum: A controversial point of view

The existence and composition of the lateral ligaments of the rectum (LLR) are still the subjects of anatomical confusion and surgical misconception up to now. Since Miles proposed abdominoperineal excision as radical surgery for rectal cancer, the identification by "hooking them on the finger" has been accepted by many surgeons with no doubt; clamping, dividing and ligating are considered to be essential procedures in mobilization of the rectum in many surgical textbooks. But in cadaveric studies, many anatomists could not find LLR described by the textbooks, and more and more surgeons also failed to find LLR during the proctectomy according to the principle of total mesorectal excision. The anatomy of LLR has diverse descriptions in literatures. According to our clinical observations, the traditional anatomical structures of LLR do exist; LLR are constant dense connective bundles which are located in either lateral side of the lower part of the rectum, run between rectal visceral fascia and pelvic parietal fascia above the levator ani, and covered by superior fascia of pelvic diaphragm. They are pathways of blood vessels and nerve fibers toward the rectum and lymphatic vessels from the lower rectum toward the iliac lymph nodes.

A non-linear finite element model of human L4-L5 lumbar spinal segment with three-dimensional solid element ligaments

This paper establishes a non-linear finite element model (NFEM) of L4-L5 lumbar spinal segment with accurate three-dimensional solid ligaments and intervertebral disc. For the purpose, the intervertebral disc and surrounding ligaments are modeled with four-nodal three-dimensional tetrahedral elements with hyper-elastic material properties. Pure moment of 10 N·m without preload is applied to the upper vertebral body under the loading conditions of lateral bending, backward extension, torsion, and forward flexion, respectively. The simulate relationship curves between generalized forces and generalized displacement of the NFEM are compared with the in vitro experimental result curves to verify NFEM. The verified results show that: (1) The range of simulated motion is a good agreement with the in vitro experimental data; (2) The NFEM can more effectively reffect the actual mechanical properties than the FE model using cable and spring elements ligaments; (3) The NFEM can be used as the basis for further research on lumbar degenerative diseases.

Ligaments disruption:a new perspective in the prognosis of spinal cord injury

The worldwide prevalence of spinal cord injury （SCI） ranges from 233 to 755 per million inhabitants, whereas the report- ed incidence lies between 10.4 and 83 per million inhabitants annually （Wyndaele and Wyndaele, 2006）. Thus, the socio- economic impact of SCI associated with cervical trauma is high enough that it could become an important concern in the vast majority of developed countries.

Mechanical properties of 65Mn chiral structure with three ligaments

Chiral honeycomb structures have been developed in recent years, showing excellent mechanical properties, including in-plane deformation and out-of-plane bearing and vibration isolation. In this study, the 65Mn chiral structure with three ligaments was modeled and analyzed using the finite element (FE) method. The effects of the dimensionless ligament length and dimensionless ligament thickness on the in-plane equivalent elastic modulus, equivalent Poisson's ratio, and out-of-plane shear modulus were studied. The numerical results indicate that increase of the dimensionless ligament length leads to decrease of the equivalent elastic modulus and increase of the equivalePoisson's ratio, whereas the out-of-plane equivalent shear modulus decreases. The results also indicate that increase of the dimensionless ligament thickness leads to in crease of the equivalent elastic modulus, whereas the equivalent Poisson's ratio remains nearly unchanged and the out-of-plane equivalent shear modulus shows a linear in crease. The numerical results are verified by comparis on with published experime ntal data. These results will provide a reference for the application of chiral structures with three ligaments in the aerospace field.

Three-dimensional finite element analysis of ligaments of lumbar spine

The lumbar ligaments play an important role in spinal biomechanics.The results ofthree-dimensional finite dement analysis showed that one of the functions of lumbar ligaments istransmission of the tensile load between the lumbar vertebrae.The anterior longitudinal ligament isloaded in extension of lumbar spine and the resistance to the tensile load in flexion is providedby other ligaments.These ligaments are subject to much more tension with degeneration of theintervertebral disc so that a series of pathological changes occur.Relevant significance in clinical as-pect is also discussed.

Magnetic resonance imaging of the ligaments of the craniocervical region at 3Tesla magnetic resonance unit: Quantitative and qualitative assessment

Purpose: The assessment of the morphology and dimensions of the craniocervical ligaments using a 3 Tesla (T) Magnetic Resonance (MR) scanner, the correlatation of our results with those from cadaveric and other MR studies and the detection of the most appropriate sequence for the best imaging of the craniovertebral junction ligaments. Methods: 58 healthy volunteers (mean age 45 years) underwent a Magnetic Resonance Imaging (MRI) of the cervical spine at 3T MR unit. The MRI protocol included axial, coronal and sagittal Proton-Density (PD) sequences and sagittal T1 Fluid Attenuated Inversion Recovery (FLAIR) and T2 sequences. The images were evaluated by two radiologists and the posterior atlantoocipital ligament, the anterior atlantoocipital ligament, the transverse ligament and the apical ligament were anatomically detected, described and measured. Results: The transverse ligament was identified at 93.1%, the apical ligament was identified at 60.34%, the posterior at- lantooccipital membrane was identified at 94.8% and the anterior atlantooccipital membrane was identified at 96.5% of the cases. All ligaments appeared with low signal intensity, except the anterior atlantooc-cipital ligament which appeared with intermediate signal intensity. Their length, width and thickness were measured and, in general, correlated well with other anatomic and MR studies. Conclusion: Reliable assessment of the morphology and signal intensity of the craniocervical ligaments can be achieved with PD sequence at 3T MR imaging. The sagittal plane provides better delineation of the craniocervical (CC) ligaments but the axial and coronal planes are of paramount importance in the assessment of the transverse and apical ligaments.

Ligament augmentation reconstruction system artificial ligaments in patellar tendon reconstruction-a chronic patellar tendon rupture after multiple operations: A case report

BACKGROUND Patellar tendon rupture is a rare disease,and reports regarding patellar tendon reconstruction with ligament augmentation reconstruction system(LARS)ligaments are limited,with only three reports available in the literature.LARS ligaments are made of polyethylene terephthalate and have been certified as a more favorable option than other tendon transplants.To our knowledge,this is the first report of patellar tendon reconstruction with LARS for suture fixation due to poor quality of the tendon after multiple operations to enable early mobilization and quick rehabilitation.CASE SUMMARY A 65-year-old woman had limited ability in extending her leg and an inability to perform a straight leg raise after multiple operations due to patella fracture.The patient underwent patellar tendon reconstruction with LARS artificial ligaments.After 12 mo of follow-up,the patient was able to perform a straight leg raise,and the incision healed well without complications.The Lysholmscore was 95 and the range of motion of the knee was 0-130°.CONCLUSION This study revealed that patellar tendon reconstruction with LARS artificial ligaments is possible in a patient with a patellar tendon rupture who required rapid postoperative recovery.

Optimization of Material Coefficients in the Holzapfel-Gasser-Ogden Material Model for the Main Four Ligaments of the Knee Joint-A Finite Element Study

Accurate representation of soft tissue material properties plays a crucial role in computational biomechanics. Several material models have been used for knee ligaments in finite element (FE) studies, including the neo-Hookean model (widely used) and the Holzapfel-Gasser-Ogden (HGO) model (seldom used). While the coefficients of neo-Hookean models for the knee ligaments are available in the literature, limited data exists for the HGO model. Furthermore, no peer-reviewed comparison of these two material models for the knee ligaments while including the 3D representation of the ligaments for both material models is present in the literature. We used mechanical properties from the tensile test experiments in the literature for each ligament to obtain the HGO material coefficients while accounting for the ligaments’ viscoelastic behavior. Resultant coefficients were then used in an Abaqus/explicit knee model to simulate bipedal landing from a jump. The simulations were repeated with neo-Hookean values from the literature. Knee kinematics plus ACL and MCL strains were evaluated and compared for these two material models. The outputs from the simulations with HGO properties were predominantly within 1.5 standard deviations from the mean in-vitro data. When the material properties changed to Neo-Hookean, the outputs for kinematics and strain values were higher than the HGO case, and in most instances, they were outside the experimental range for ACL and MCL strains (by up to 11.35 SD) as well as some ITR angles (by up to 2.86 SD). Reported HGO material model with optimized coefficients produces a more realistic representation of the ligaments’ material properties, and will help improve the outcomes of FE models for more accurate predictions of knee behavior.

Abstraction and operator characterization of fractal ladder viscoelastic hyper-cell for ligaments and tendons

This study investigates the viscoelastic behavior of soft bio-fibres in association with their fractal structures. A spring-dashpot fractal network with the self-similar topology, named the -type fractal ladder hyper-cell (FLHC), is abstracted from the micro/nano-structure of ligaments and tendons (LTs). Its constitutive operator is derived by the Heaviside operational calculus, which is of intrinsic fractional order. In terms of this operator, the long-term viscoelastic relaxation of bio-fibres arising from the fractal ladder topology is expounded. In addition, the fractional-order viscoelastic constitutive equation is obtained based on the FLHC of LTs, and its results are consistent with those of available human knee and spinal LT relaxation experiments. Results on the constitutive equation of FLHCs are formulated into two propositions. The multidisciplinary invariance and implications from the fractal ladder pattern of bio-fibres are also discussed.

Arthroscopic anatomical reconstruction of lateral collateral ligaments with ligament advanced reinforcement system artificial ligament for chronic ankle instability

BACKGROUND Recently,the use of ligament advanced reinforcement system(LARS)artificial ligament,a new graft which has several unique advantages such as no donor-site morbidity,early recovery and no risk of disease transmission which has been a significant breakthrough for anatomical ligament reconstruction.Growing studies suggested that the special design of the LARS ligament with open fibers in its intra-articular part was believed to be more resistant to torsional fatigue and wearing.However,the safety and efficacy of LARS artificial ligament for ankle joint lateral collateral ankle ligament reconstruction has not been defined to date.AIM To evaluate the clinical results of all-arthroscopic anatomical reconstruction of ankle joint lateral collateral ligaments with the LARS artificial ligament for chronic ankle instability.METHODS Twenty-two patients with chronic lateral instability underwent anatomical reconstruction of the lateral collateral ligaments of ankle with LARS artificial ligament.The visual analogue score(VAS),American Orthopaedic Foot and Ankle Society score(AOFAS score)and Karlsson score were used to evaluate the clinical results before and after surgery.RESULTS A total of 22 patients(22 ankles)were followed up for a mean of 12 mo.All patients reported significant improvement compared to their preoperative status.The mean AOFAS score improved from 42.3±4.9 preoperatively to 90.4±6.7 postoperatively.The mean Karlsson score improved from 38.5±3.2 preoperatively to 90.1±7.8 postoperatively.The mean VAS score improved from 1.9±2.5 preoperatively to 0.8±1.7 postoperatively.CONCLUSION All-arthroscopic anatomical reconstruction of the lateral collateral ligaments with LARS artificial ligament achieved a satisfactory surgical outcome for chronic ankle instability.

How should congenital absence of cruciate ligaments be treated? A case report and literature review

BACKGROUND Hypoplasia of bilateral cruciate ligaments is a rare congenital malformation.The diagnosis of such diseases and indications for the various treatment options require further analysis and discussion.CASE SUMMARY The patient is a 26-year-old Chinese woman who has been suffering from knee pain since the age of 8 years,2-3 episodes a year.Three years ago,due to the practice of advanced yoga poses,the frequency of left knee pain increased,requiring prompt medical treatment.Magnetic resonance imaging demonstrated an absence of both anterior and posterior cruciate ligaments of both knees with abnormal posterior tilting of the tibial plateau.Bilateral subluxation of the knee joint was also found,therefore tibial osteotomy was performed.The patient reported at the 24 mo follow-up that the frequency of pain and instability had been reduced and function restored.CONCLUSION Osteotomy may be an effective method to treat patients with congenital cruciate ligament deficiency with posterior tibial plateau tilting.The diagnosis of congenital cruciate ligament deficiency shall be based on the combination of patient’s medical history,clinical manifestations,and findings from imaging to avoid possible misdiagnosis.Based on the symptoms,frequency of attacks,and intent of the individual,appropriate treatment options shall be identified.

ASME Section Ⅲ Stress Analysis of a Heat Exchanger Tubesheet with a Misdrilled Hole and Irregular or Thin Ligaments

A stress analysis is described for a nuclear steam generator tubesheet with a thin, or irregular ligament, associated with a mis-drilled hole using the rules of ASME （American Society of Mechanical Engineers） B ＆ PV Section Ⅲ and non-mandatory Appendix A, Article A-8000 for stresses in perforated flat plates. The analysis demonstrates the proper application of the NB-3200 rules for this special application, with discussion of the differences between an actual tube hole deviation and what is assumed in ASME Appendix A. This is a companion paper to ＂Technical Justification Supporting Operation with a Tube Installed in a Mis-Drilled Hole of a Steam Generator Tubesheet＂.

Analysis of oil shedding and ligaments formation on bearing rotary elements

For designing efficient lubrication system of an aeroengine bearing chamber,sufficient knowledge on oil/air two-phase flow characteristics is required.When analyzing bearing chamber two-phase flow,the essential prerequisite is quantifying the oil ligaments,which are detached from bearing rotary elements and shed into the bearing chamber.Related investigations are mainly targeted at liquid shedding on the rotating disk as opposed to the bearing rotary elements.Moreover,the research based on bearing rotary elements is conducted by experiment.Due to the limited operating conditions,experimental studies cannot guide engineering applications.To overcome these limitations,a theoretical model is established in this paper,for revealing the mechanism of oil shedding from bearing rotary elements and quantifying the shedding ligaments.The theoretical model is validated against experimental results from classical studies.In addition,the correlation for shedding ligaments number based on aeroengine bearing structural and operational parameters is obtained via theoretical analysis.The analytical results demonstrate that oil shedding and ligaments formation appear at the edge of bearing inner race outer-periphery.The number of shedding ligaments increases with the rise of shaft rotational speed while decreases with the growth of oil viscosity.

Black tantalic oxide submicro-particles coating on PEEK fibers woven into fabrics as artificial ligaments with photothermal antibacterial effect and osteogenic activity for promoting ligament-bone healing

Design of artificial ligaments possessing both osteogenic activity and antibacterial effect that promotes ligament-bone healing and prevents bacterial infection in bone tunnels for anterior cruciate ligament(ACL)reconstruction remains a significant challenge.In this study,black tantalic oxide(BTO)submicro-particles with oxygen vacancies and structure defects were fabricated by using traditional white tan-talic oxide(WTO)through magnesium thermal reduction(MTR)method,and BTO was coated on polyetheretherketone(PEEK)fibers(PKF),which were woven into fabrics(PBT)as artificial ligaments.PBT with BTO coating exhibited excellent photothermal performance,which possessed not only antibac-terial effects in vitro but also anti-infective ability in vivo.PBT with optimized surface properties(e.g.,submicro-topography and hydrophilicity)not only significantly facilitated rat bone mesenchymal stem cells(BMSC)responses(e.g.,proliferation and osteogenic differentiation)in vitro but also stimulated new bone formation for ligament-bone healing in vivo.The presence of oxygen vacancies and structure de-fects in BTO did not change the surface properties and osteogenic activity of BPT while displaying an outstanding photothermal antibacterial effect.In summary,BPT with osteogenic activity and photother-mal antibacterial effect promoted bone regeneration and prevented bacterial infection,thereby promoting ligament-bone healing.Therefore,PBT would have tremendous potential as a novel artificial ligament for ACL reconstruction.

Laparoscopic left hemihepatectomy guided by indocyanine green fluorescence: A cranial-dorsal approach

BACKGROUND Advancements in laparoscopic technology and a deeper understanding of intra-hepatic anatomy have led to the establishment of more precise laparoscopic hepatectomy(LH)techniques.The indocyanine green(ICG)fluorescence navi-gation technique has emerged as the most effective method for identifying hepatic regions,potentially overcoming the limitations of LH.While laparoscopic left hemihepatectomy(LLH)is a standardized procedure,there is a need for innova-tive strategies to enhance its outcomes.important anatomical markers,surgical skills,and ICG staining methods.METHODS Thirty-seven patients who underwent ICG fluorescence-guided LLH at Qujing Second People's Hospital between January 2019 and February 2022 were retrospectively analyzed.The cranial-dorsal approach was performed which involves dissecting the left hepatic vein cephalad,isolating the Arantius ligament,exposing the middle hepatic vein,and dissecting the parenchyma from the dorsal to the foot in order to complete the anatomical LLH.The surgical methods,as well as intra-and post-surgical data,were recorded and analyzed.Our hospital’s Medical Ethics Committee approved this study(Ethical review:2022-019-01).RESULTS Intraoperative blood loss during LLH was 335.68±99.869 mL and the rates of transfusion and conversion to laparotomy were 13.5%and 0%,respectively.The overall incidence of complications throughout the follow-up(median of 18 months;range 1-36 months)was 21.6%.No mortality or severe complications(level IV)were reported.CONCLUSION LLH has the potential to become a novel,standardized approach that can effectively,safely,and simply expose the middle hepatic vein and meet the requirements of precision surgery.

Go to the back before going forward:Addressing psychological responses in anterior cruciate ligament reconstruction rehabilitation

Helping athletes return to sports participation is a primary goal of anterior cruciate ligament(ACL)reconstruction rehabilitation.To facilitate the achievement of this goal,decades of research studies have sought to identify knee impairments that reduce knee function as well as interventions to resolve them.1Yet,over the past 10 years,research pertaining to psychological responses(i.e.,cognitions and emotions)after ACL reconstruction has grown exponentially—a phenomenon that can be visualized by entering the search terms"psychological"and"anterior cruciate ligament reconstruction"into the PubMed search engine.

Sorafenib inhibits ossification of the posterior longitudinal ligament by blocking LOXL2-mediated vascularization

Ossification of the Posterior Longitudinal Ligament(OPLL)is a degenerative hyperostosis disease characterized by the transformation of the soft and elastic vertebral ligament into bone,resulting in limited spinal mobility and nerve compression.Employing both bulk and single-cell RNA sequencing,we elucidate the molecular characteristics,cellular components,and their evolution during the OPLL process at a single-cell resolution,and validate these findings in clinical samples.This study also uncovers the capability of ligament stem cells to exhibit endothelial cell-like phenotypes in vitro and in vivo.Notably,our study identifies LOXL2 as a key regulator in this process.Through gain-and loss-of-function studies,we elucidate the role of LOXL2 in the endothelial-like differentiation of ligament cells.It acts via the HIF1A pathway,promoting the secretion of downstream VEGFA and PDGF-BB.This function is not related to the enzymatic activity of LOXL2.Furthermore,we identify sorafenib,a broad-spectrum tyrosine kinase inhibitor,as an effective suppressor of LOXL2-mediated vascular morphogenesis.By disrupting the coupling between vascularization and osteogenesis,sorafenib demonstrates significant inhibition of OPLL progression in both BMP-induced and enpp1 deficiency-induced animal models while having no discernible effect on normal bone mass.These findings underscore the potential of sorafenib as a therapeutic intervention for OPLL.

In vitro performance of a biodegradable zinc alloy adjustable-loop cortical suspension fixation for anterior cruciate ligament reconstruction

Anterior cruciate ligament(ACL)injuries of the knee are one of the most common and serious athletic injuries.The widely used cortical suspension fixation buttons for ligament reconstruction are permanent implants,particularly those made from conventional steel or titanium alloys.In this study,a biodegradable Zn-0.45Mn-0.2Mg(ZMM42)alloy with the yield strength of 300.4 MPa and tensile strength of 329.8 MPa was prepared through hot extrusion.The use of zinc alloys in the preparation of cortical suspension fixation buttons was proposed for the first time.After 35 d of immersion in simulated body fluids,the ZMM42 alloy fixation buttons were degraded at a rate of 44μm/a,and the fixation strength was retained(379.55 N)in the traction loops.Simultaneously,the ZMM42 alloy fixation buttons exhibited an increase in MC3T3-E1 cell viability and high antibacterial activity against Escherichia coli and Staphylococcus aureus.These results reveal the potential of biodegradable zinc alloys for use as ligament reconstruction materials and for developing diverse zinc alloy cortical suspension fixation devices.