Meniscus tears treatment:The good,the bad and the ugly-patterns classification and practical guide

Over the years,several studies demonstrated the crucial role of knee menisci in joint biomechanics.As a result,save the meniscus has become the new imperative nowadays,and more and more studies addressed this topic.The huge amount of data on this topic may create confusion in those who want to approach this surgery.The aim of this review is to provide a practical guide for treatment of meniscus tears,including an overview of technical aspects,outcomes in the literature and personal tips.Taking inspiration from a famous movie directed by Sergio Leone in 1966,the authors classified meniscus tears in three categories:The good,the bad and the ugly lesions.The inclusion in each group was determined by the lesion pattern,its biomechanical effects on knee joint,the technical challenge,and prognosis.This classification is not intended to substitute the currently proposed classifications on meniscus tears but aims at offering a readerfriendly narrative review of an otherwise difficult topic.Furthermore,the authors provide a concise premise to deal with some aspects of menisci phylogeny,anatomy and biomechanics.

Recent advances in meniscus-on-demand three-dimensional micro-and nano-printing for electronics and photonics

The continual demand for modern optoelectronics with a high integration degree and customized functions has increased requirements for nanofabrication methods with high resolution,freeform,and mask-free.Meniscus-on-demand three-dimensional(3D)printing is a high-resolution additive manufacturing technique that exploits the ink meniscus formed on a printer nozzle and is suitable for the fabrication of micro/nanoscale 3D architectures.This method can be used for solution-processed 3D patterning of materials at a resolution of up to100 nm,which provides an excellent platform for fundamental scientific studies and various practical applications.This review presents recent advances in meniscus-on-demand 3D printing,together with historical perspectives and theoretical background on meniscus formation and stability.Moreover,this review highlights the capabilities of meniscus-on-demand 3D printing in terms of printable materials and potential areas of application,such as electronics and photonics.

An Improved Transosseous Pullout Suture Technique for Arthroscopic Repair of a Meniscus Root Tear

Objective:This study aimed to explore the clinical efficiency of an improved transosseous pullout suture technique for arthroscopic repair of a meniscus root tear.Methods:From January 2017 to January 2021,53 patients with posterior meniscus root tears combined with anterior cruciate ligament(ACL)and/or posterior cruciate ligament(PCL)tears were collected.Totally,in 29 patients(group A),the 2.0 mm modified pullout tunnel method was used to suture the posterior meniscus root,while 24 patients(group B)were treated with the traditional 4.5 mm pullout tunnel method.In group A,20 patients had lateral meniscus posterior root(LMPR)combined with ACL tears,5 patients had LMPR combined with ACL and PCL tears,and 4 patients had medial meniscus posterior root(MMPR)combined with ACL tears.In group B,19 patients had LMPR combined with ACL tears,3 patients had LMPR combined with ACL and PCL tears,and 2 patients had MMPR combined with ACL tears.The improvement of the Lysholm and VAS scores and the incidence of complications in group A and group B before the operation,1 month and 3 months after the operation,and after the final follow-up were compared.Results:Preoperative Lysholm score was 26.0±5.6 in group A and 26.7±5.8 in group B(P>0.05).One-month postoperative Lysholm score was 66.5±5.7 in group A and 54.3±2.4 in group B(P<0.001).Three-month postoperative Lysholm score was 81.1±7.2 in group A and 73.2±9.7 in group B(P<0.05).Lysholm scores after the final follow-up was 90.3±5.6 in group A and 90.0±5.0 in group B(P>0.05).Preoperative VAS score was 6.3±1.4 in group A and 6.3±1.2 in group B(P>0.05).One-month postoperative VAS score was 1.8±0.7 in group A and 2.4±0.9 in group B(P<0.05).Three-month postoperative VAS score was 0.7±0.6 in group A and 0.8±0.6 in group B(P>0.05).VAS score after the final follow-up was 0.2±0.4 in group A and 0.3±0.5 in group B(P>0.05).Conclusion:The improved transosseous pullout suture technique using a smaller 2.0 mm bone tunnel can virtually eliminate the risk of conflict with other bone tunnels and facilitate the management of bone tunnels in multiple ligament injuries,while also diminishing suture abrasion caused by the windshield wiper effect.The technique achieves good clinical efficacy.

Dynamic tear meniscus parameters in complete blinking:insights into dry eye assessment

AIM:To investigate the relationship between dynamic tear meniscus parameters and dry eye using an automated tear meniscus segmentation method.METHODS:The analysis of tear meniscus videos captured within 5s after a complete blink includes data from 38 participates.By processing video data,several key parameters including the average height of the tear meniscus at different lengths,the curvature of the tear meniscus’s upper boundary,and the total area of the tear meniscus in each frame were calculated.The effective values of these dynamic parameters were then linearly fitted to explore the relationship between their changing trends and dry eye disease.RESULTS:In 94.74%of the samples,the average height of central tear meniscus increased over time.Moreover,97.37%of the samples exhibited an increase in the overall tear meniscus height(TMH)and area from the nasal to temporal side.Notably,the central TMH increased at a faster rate compared to the nasal side with the temporal side showing the slowest ascent.Statistical analysis indicates that the upper boundary curvature of the whole tear meniscus as well as the tear meniscus of the nasal side(2,3,and 4 mm)aid in identifying the presence of dry eye and assessing its severity.CONCLUSION:This study contributes to the understanding of tear meniscus dynamics as potential markers for dry eye,utilizing an automated and non-invasive approach that has implications for clinical assessment.

基于二维Meniscus透镜的准光功率合成器(英文)

为了实现大功率容量和高效率的空间功率合成,将基于波导腔体的二维Meniscus透镜用于毫米波功率合成器的设计.对透镜中传输的主模(TE10波)的散射效应进行了分析,并且设计了匹配层减小透镜结构带来的反射.在30GHz频率上利用Rexolite介质的Meniscus透镜设计出了10路功率合成器,对不同结构的功率合成器和不同参数的透镜进行了研究,得到了最终的优化结果.CST-MMW的仿真结果表明该功率合成器在30GHz合成效率可以达到92.6%,并且其80%以上效率工作带宽可以覆盖整个Ka波段.

Degenerative meniscus: Pathogenesis, diagnosis, and treatment options

The symptomatic degenerative meniscus continues to be a source of discomfort for a significant number of patients. With vascular penetration of less than onethird of the adult meniscus, healing potential in the setting of chronic degeneration remains low. Continued hoop and shear stresses upon the degenerative meniscus results in gross failure, often in the form of complex tears in the posterior horn and midbody. Patient history and physical examination are critical to determine the true source of pain, particularly with the significant incidence of simultaneous articular pathology. Joint line tenderness, a positive Mc Murray test, and mechanical catching or locking can be highly suggestive of a meniscal source of knee pain and dysfunction. Radiographs and magnetic resonance imaging are frequently utilized to examine for osteoarthritis and to verify the presence of meniscal tears, in addition to ruling out other sources of pain. Non-operative therapy focused on nonsteroidal anti-inflammatory drugs and physical therapy may be able to provide pain relief as well as improve mechanical function of the knee joint. For patients re-fractory to conservative therapy, arthroscopic partial meniscectomy can provide short-term gains regarding pain relief, especially when combined with an effective, regular physiotherapy program. Patients with clear mechanical symptoms and meniscal pathology may benefit from arthroscopic partial meniscectomy, but surgery is not a guaranteed success, especially with concomitant articular pathology. Ultimately, the long-term outcomes of either treatment arm provide similar results for most patients. Further study is needed regarding the short and long-term outcomes regarding conservative and surgical therapy, with a particular focus on the economic impact of treatment as well.

Lipid layer thickness and tear meniscus height measurements for the differential diagnosis of evaporative dry eye subtypes

AIM: To explore a new diagnostic index for differentiating the evaporative dry eye(EDE) subtypes by analysis of their respective clinical characteristics. METHODS: A cross-sectional study of 139 patients(139 eyes) with EDE who were enrolled and classified as obstructive meibomian gland dysfunction(MGD)(n=81) and non-obstructive MGD(n=58) EDE. All patients completed a Standard Patient Evaluation of Eye Dryness(SPEED) questionnaire and were evaluated for average lipid layer thickness(LLT), tear meniscus height measurements(TMH), tear break-up time(TBUT), ocular surface staining score, Schirmer I test(SIT), lid margin abnormalities, and meibomian gland function and morphology. RESULTS: Age, average LLT, TMH, scores of lid margin abnormalities, meibum quality, meibomian gland loss(MGL)(all P≤0.001), and TBUT(P=0.03) were all significantly different between obstructive MGD EDE patients and nonobstructive MGD EDE patients. Average LLT in obstructive MGD EDE was correlated with meibomian expressibility(r=-0.541, P≤0.001), lid margin abnormalities were marginally not significant(r=0.197, P=0.077), and TMH was correlated with MGL(total MGL: r=0.552, P≤0.001; upper MGL: r=0.438, P≤0.001; lower MGL: r=0.407, P≤0.001). Average LLT in non-obstructive MGD EDE, was correlated with meibomian expressibility and Oxford staining(r=-0.396, P=0.002; r=-0.461, P≤0.001). The efficiency of combining average LLT and TMH was optimal, with a sensitivity of 80.2% and a specificity of 74.1%. Obstructive MGD EDE patients had an average LLT≥69 nm and TMH≥0.25 mm, while non-obstructive MGD EDE patients had an average LLT<69 nm and TMH<0.25 mm.CONCLUSION: Obstructive MGD EDE and nonobstructive MGD EDE have significantly different clinical characteristics. Combining average LLT and TMH measurements enhanced their reliability for differentiating these two subtypes and provided guidance for offering more precise treatments for EDE subtypes.

Indirect printing of hierarchical patient-specific scaffolds for meniscus tissue engineering

The complex meniscus tissue plays a critical role in the knee. The high susceptibility to injury has led to an intense pursuit for better tissue engineering regenerative strategies, where scaffolds play a major role. In this study, indirect printed hierarchical multilayered sca ffolds composed by a silk fibroin (SF) upper layer and an 80/20 (w/w) ratio of SF/ionic-doped β-tricalcium phosphate (TCP) bottom layer were developed. Furthermore, a comparative analysis between two types of sca ffolds pro- duced using di fferent SF concentrations, i.e., 8% (w/v) (Hi8) and 16% (w/v) (Hi16) was performed. In terms of architecture and morphology, the produced sca ffolds presented homogeneous porosity in both layers and no di fferences were observed when comparing both sca ffolds. A decrease in terms of mechanical performance of the sca ffolds was observed when SF concentration decreased from 16 to 8% (w/v). Hi16 revealed a static compressive modulus of 0.66 ± 0.05 MPa and dynamical mechanical properties ranging from 2.17 ± 0.25 to 3.19 ± 0.38 MPa. By its turn, Hi8 presented a compressive modulus of 0.27 ± 0.08 MPa and dynamical mechanical properties ranging from 1.03 ± 0.08 MPa to 1.56 ± 0.13 MPa. In vitro bioactivity studies showed formation of apatite crystals onto the surface of Hi8 and Hi16 bottom layers. Human meniscus cells (hMCs) and human primary osteoblasts were cultured separately onto the top layer (SF8 and SF16) and bottom layer (SF8/TCP and SF16/TCP) of the hierarchical sca ffolds Hi8 and Hi16, respectively. Both cell types showed good adhesion and proliferation as denoted by the live/dead staining, Alamar Blue assay and DNA quanti fication analysis. Subcutaneous implantation in mice revealed weak in flammation and sca ffold’s integrity. The hierarchical indirect printed SF sca ffolds can be promising candidate for meniscus TE sca ffolding applications due their suitable mechanical properties, good biological performance and possibility of being applied in a patient-speci fic approach.

SOME CHARACTERISTICS OF LIQUID METAL MENISCUS IN ELECTROMAGNETIC FIELD

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Meniscus fabrication of halide perovskite thin films at high throughput for large area and low-cost solar panels

Halide perovskites have rapidly attracted considerable attention due to unprecedented properties not seen in traditional semiconductors.In addition to their optoelectronic merits,one advantage of perovskite materials is their solution processability,which opens the door to low-cost and high throughput solution coating strategies for the commercialization of perovskite solar cells(PSCs).Here we review perovskite film fabrication by meniscus coating—a simple and readily scalable manufacturing technique,including blade coating and slot-die coating.We outline the fundamental fluid mechanisms of meniscus coating,discuss drying and crystallization of perovskite in the coating process,and provide an overview of recent progress in meniscus-coated PSCs.

Arterial sunoly of the meniscus of knee ioint

The arterial supply of the genicular meniscus was studied with macro-microanatomical and histological examinations,translucent preparations and scanning electronmicroscopy.It was found that the menisci were supplied by the articular branches of thepopliteal artery except the lateral superior genicular branch and the descending genicularartery.Among them there were two genicular branches with independent stems from thepopliteal artery,named as the posterior medial and posterior lateral genicular artery,whichsupplied the posterior part of the corresponding meniscus.The genicular branchesanastomosed with each other to form a vascular circle around the menisci,and minutebranches from the circle formed an arterial network around the menisci and terminated incapillaries in 3 types of anastomotic forms.The surgical approach to the menisci and theprognosis of an injured meniscus were discussed on the basis of the arterial distributionsinside and outside of the menisci.

Simulation of liquid meniscus formation in the ionic liquid electrospray process

Though tremendous efforts have been made to investigate electrospray,some aspects,such as the evolution of the menisci on the micropores of porous emitter tips and the transient response of the meniscus during the polarity alternation,need to be further understood.This paper presents a computation fluid dynamics(CFD)model to describe the meniscus formation in the ionic liquid electrospray process.The CFD model,based on the Taylor–Melcher leaky dielectric fluid theory and the volume of fluid(VOF)method,is validated by experiments.The evolution of the meniscus on the basis of a micropore is presented using two typical ionic liquids,EMI-BF_(4) and EMI-Im.The influences of the pore size,flow rate and applied voltage on the formation of the meniscus have been studied.Results show that a larger pore is more likely to start emission,and the time consumed for liquid meniscus formation decreases with increasing applied voltage and flow rate.Further,it is found that alternation of polarity does not destroy the structure of the meniscus but retards the formation process,and a faster polarity alteration leads to a shorter delay in meniscus formation time.

A novel bio‑active microsphere for meniscus regeneration via inducing cell migration and chondrocyte differentiation

Abstract Meniscus injury is a common disease in clinic.If it was not treated in time,it leads to osteoarthritis which brings unbearable pain and heavy economic burden to the patients.At present,meniscectomy and meniscus suture are widely used in the treatment for meniscus injury.Nevertheless,It is not ideal for poor self-healing ability of meniscus.The recruitment of endogenous stem cells is an attractive option for wounded meniscus healing.Fully reduced high-mobility group box 1 protein(HMGB1)can accelerate the regeneration of multiple tissues by endogenous stem cell activation,migration and differentiation.Kartogenin(KGN)has shown to induce the chondrogenesis of the stem cells.However,no study has explored such effects of HMGB1 and KGN in wounded meniscus healing.Therefore,in order to improve the regeneration of meniscus,we intend to use a novel bioactive microsphere which was developed by combining fully reduced high mobility group box 1(frHMGB1)and kartogenin(KGN)with alginate gel which slowly release high concentrations of HMGB1 and KGN to activate rat bone marrow stem cells(BMSCs)and promote cell proliferation.The results showed that this HMGB1–KGN microsphere released and kept high concentrations of HMGB1 and KGN in the wound area for more than 2 weeks.In vitro experimental results showed that the HMGB1–KGN microsphere can promote cell proliferation via recruiting rat bone marrow stem cells(BMSCs)and activating the BMSCs from G_(0) to G_(Alert) stage as evidenced by cell migration testing and 5-bromo-2′-deoxyuridine(BrdU)incorporation assay.In vivo results indicated that this HMGB-KGN microsphere can recruit GFP-labeled BMSCs from tail vein to wounded meniscus and induce these GFP-labeled BMSCs to differentiate into chondrocytes.Our results demonstrated that the HMGB1–KGN-containing bioactive microsphere induced cell migration in vitro and recruited the cells to wound area to promote wounded rat meniscus healing in vivo.

Discoid medial meniscus of both knees:A case report

BACKGROUND Discoid meniscus is a congenital anomaly that typically affects the lateral meniscus.The appearance of the discoid medial meniscus in both knees is extremely rare,with an incidence of only 0.012%.CASE SUMMARY Our patient was a 30-year-old female.Under no obvious predisposing causes,she began to experience pain in both knees,which worsened while walking and squatting.The pain was aggravated after exercise,and joint flexion and extension activities were accompanied by knee snapping.Apley’s test was positive on physical examination,and there was a pressing pain in the medial articular space.Plain radiographs of both knees revealed no obvious abnormalities in the bilateral knee joint space.Partial meniscectomy as well as menisci reformation were performed on both knees under arthroscopy.Under the guidance of rehabilitation,the patient’s range of motion in both knees returned to normal without pain and knee snapping.CONCLUSION This study showed that the clinical manifestations of the discoid medial meniscus injury are identical to those of the conventional medial meniscus injury,and arthroscopic surgery is effective.

ARTHROSCOPIC TREATMENT FOR DISCOID LATERAL MENISCUS INJURY OF THE KNEE IN CHILDREN

Objective To study the arthroscopic treatment results for discoid lateral meniscus injury of the knee in children. Methods 74 children patients, including 98 knees underwent arthroscopic treatment due to discoid lateral meniscus injury were followed up. By Watanabe classification, incomplete discoid menis-cus was seen in 34 knees, complete in 42 and Wrisberg type in 22. The methods of treatment were partial, subtotal or total meniscectomy. The follow-up time ranged from 3 to 24 months, averaged 8 months. The re-sults were analyzed according to Lysholm knee evaluation method. Results By Lysholm evaluation the re-sults were excellent in 68 knees (69. 4%) and good in 30 (30. 6%). Conclusion Arthroscopic treatment is a reliable way for discoid lateral meniscus injury in children.

Discoid meniscus:Treatment considerations and updates

A discoid meniscus is a morphological abnormality wherein the meniscus loses its normal‘C’shape.Although most patients are asymptomatic,patients might still present with symptoms such as locking,pain,swelling,or giving way.Magnetic resonance imaging is usually needed for confirmation of diagnosis.Based on a constellation of factors,including clinical and radiological,different approaches are chosen for the management of discoid meniscus.The purpose of this review is to outline the treatment of discoid meniscus,starting from conservative approach,to the different surgical options for this condition.The PubMed and Google Scholar databases were used for this review.Studies discussing the treatment of discoid meniscus from 2018 to 2023 were searched.Initially there were 369 studies retrieved,and after removal of studies using the exclusion criteria,26 studies were included in this review.Factors such as stability,presence of tear,and morphology can help with surgical planning.Many approaches have been used to treat discoid meniscus,where the choice is tailored for each patient individually.Postoperatively,factors that may positively impact patient outcomes include male sex,body mass index<18.5,age at symptom onset<25 years,and duration of symptoms<24 months.The conventional approach is partial meniscectomy with or without repair;however,recently,there has been an increased emphasis on discoid-preserving techniques such as meniscoplasty,meniscopexy,and meniscal allograft transplantation.

Congenital absence of the lateral meniscus:A case report

BACKGROUND Congenital absence of the menisci is a rare anatomical variation characterized by the absence or underdevelopment of one or both menisci in the knee joint.The menisci are crucial in load distribution,joint stability,and shock absorption.Understanding the clinical presentation,diagnosis,and management of this condition is important for optimal patient care.CASE SUMMARY A 27-year-old male with a long-standing history of knee pain underwent diagnostic arthroscopy,revealing a congenital absence of the meniscus.The patient's clinical findings,imaging results,surgical procedures,and pertinent images are detailed.This case presents a unique aspect with the congenital absence of the meniscus,contributing valuable insights to the literature on rare anatomical anomalies.CONCLUSION This case of congenital absence of the menisci highlights the diagnostic challenges posed by rare anomalies.The diagnostic arthroscopy played a crucial role in identifying the absence of the meniscus and providing an explanation for the patient's persistent knee pain.The case underscores the importance of individualized treatment approaches,including physical therapy,for optimal management of rare meniscal anomalies.Further research is warranted to explore effective management strategies for the aforementioned cases and to expand our knowledge of these rare conditions.

Variation of meniscus shape and initial steel solidification under different steel-slag interfacial tension in continuous casting mold of slab

A two-dimensional model was applied to investigate the influence of the interfacial tension between the steel and the slag on the behavior of the meniscus in continuous casting mold of slab.The shape of the meniscus and phenomena near the meniscus were revealed,and the profile of the slag rim and the depth of the solidified meniscus and oscillation marks with different interfacial tension of the steel and slag were compared.With the increase in the interfacial tension,the size of the curved meniscus increased,while the curvature and the height of the local meniscus close to the mold decreased.Besides,the thickness of the slag rim,solid slag and total slag near the meniscus had the tendency to increase,and the bottom of the slag rim became lower and thicker.With the increase in the interfacial tension from 0.1 to 2.5 N/m,the location of the largest heat flux near the meniscus decreased from 10.0 to 2.5 mm above the initial level of the steel,and the largest heat flux was within 3.52-4.58 MW/m^(2).Meanwhile,the largest depth of the solidified meniscus decreased from 3.3 to 2.3 mm,and the depth of oscillation marks decreased,which was conducive to the shallow hook at the subsurface of the slab,and the improvement of surface cleanliness of the slab.

A gel microparticle-based self-thickening strategy for 3D printing high-modulus hydrogels skeleton cushioned with PNAGA hydrogel mimicking anisotropic mechanics of meniscus

Developing a meniscus substitute mimicking the anisotropic mechanics(higher circumferential tensile modulus and lower compressive modulus)of native tissue remains a great challenge.In this work,based on the pendant group structure-dependent H-bonding strengthening mechanism,two kinds of amide-based H-bonding crosslinked hydrogels with distinct mechanical behaviors,that is,the flexible poly(N-acryloyl glycinamide)(PNAGA)and the ultra-stiff poly(N-acryloylsemicarbazide)(PNASC)hydrogels are employed to construct the biomimetic meniscus substitute.To this end,a gel microparticle-based self-thickening strategy is first proposed to fabricate PNASC(GMP-PNASC)high-modulus hydrogels skeleton by extrusion printing technology in mimicking the collagen fibers in native meniscus to resist the circumferential tensile stress.Then,the PNAGA hydrogel is infused into the PNASC skeleton to replicate the proteoglycan,providing a lower compressive modulus.By regulating the structural features at the interior and peripheral regions,the GMP-PNASC/PNAGA hydrogel meniscus scaffold with the higher tensile modulus(87.28±6.06 MPa)and lower compressive modulus(2.11±0.28 MPa)can be constructed.In vivo outcome at 12 weeks post-implantation of rabbit’s medial meniscectomy model confirms the effects of GMP-PNASC/PNAGA meniscus scaffold on alleviating the wear of articular cartilage and ameliorating the development of osteoarthritis(OA).

Advanced bioactive glue tethering Lubricin/PRG4 to promote integrated healing of avascular meniscus tears

Meniscus injuries are extremely common with approximately one million patients undergoing surgical treatment annually in the U.S. alone, but no regenerative therapy exist. Previously, we showed that controlled applications of connective tissue growth factor (CTGF) and transforming growth factor beta 3 (TGFβ3) via fibrin-based bio-glue facilitate meniscus healing by inducing recruitment and stepwise differentiation of synovial mesenchymal stem/progenitor cells. Here, we first explored the potential of genipin, a natural crosslinker, to enhance fibrin-based glue’s mechanical and degradation properties. In parallel, we identified the harmful effects of lubricin on meniscus healing and investigated the mechanism of lubricin deposition on the injured meniscus surface. We found that the pre-deposition of hyaluronic acid (HA) on the torn meniscus surface mediates lubricin deposition. Then we implemented chemical modifications with heparin conjugation and CD44 on our bioactive glue to achieve strong initial bonding and integration of lubricin pre-coated meniscal tissues. Our data suggested that heparin conjugation significantly enhances lubricin-coated meniscal tissues. Similarly, CD44, exhibiting a strong binding affinity to lubricin and hyaluronic acid (HA), further improved the integrated healing of HA/lubricin pre-coated meniscus injuries. These findings may represent an important foundation for developing a translational bio-active glue guiding the regenerative healing of meniscus injuries.