UNASSIGNED: Meniscal root tears are defined as soft-tissue and/or osseous injuries that rip or avulse within one centimeter of the meniscal insertion to the tibial plateau. These injuries impact around 100,000 patients a year and make up 10 % to 21 % of all meniscal tears. Meniscal extrusion frequently happens when there are root rips, and the transmission of circumferential hoop loads is hampered.
METHODS: We present one case of a 28-year-old male who complained of pain and stiffness in his left knee since 2 years after undergoing ACL reconstruction using a hamstring autograft. His examination revealed joint line tenderness on both the medial and lateral sides of the left knee. Further investigations involving X-ray and MRI established the diagnosis of both medial and lateral meniscal root tears, which were surgically managed using the transtibial pullout technique.
CONCLUSIONS: The biomechanical implications of meniscal root tears, such as loss of hoop forces and increased tibiofemoral contact pressures, underscore the importance of timely diagnosis and management. The literature advocates surgical treatment for managing root tears, as leaving them without surgical intervention can lead to functional outcomes similar to those of total meniscectomy.
CONCLUSIONS: This case report presents both menisci posterior root tears with an intact ACL graft which is unique in that they commonly tear in conjuction with ACL. These kind of injuries necessitates prompt diagnosis and surgical intervention to protect the knee from early arthritic changes.

BACKGROUND: Meniscal sparing surgery is a widely utilised treatment option for unstable meniscal tears with the aim of minimising the risk of progression towards osteoarthritis. However, there is limited data in the literature on meniscal repair outcomes in skeletally immature patients.
OBJECTIVE: To evaluate the re-operation rate and functional outcomes of meniscal repairs in children and adolescents.
METHODS: We performed a retrospective review of all patients who underwent arthroscopic meniscal repair surgery between January 2007 and January 2018. All patients were under the age of 18 at the time of surgery. Procedures were all performed by a single surgeon. Information was gathered from our hospital Electronic Patient Records system. The primary outcome measure was re-operation rate (need for further surgery on the same meniscus). Secondary outcome measures were surgical complications and patient reported outcome measures that were International Knee Documentation Committee (IKDC), Tegner and Lysholm scores.
RESULTS: We identified 59 patients who underwent 66 All-inside meniscal repairs (32 medial meniscus and 34 Lateral meniscus). Meniscal repairs were performed utilizing FasT-Fix (Smith and Nephew) implants. There were 37 males and 22 females with an average age of 14 years (range 6-16). The average follow-up time was 53 months (range 26-140). Six patients had concomitant anterior cruciate ligament reconstruction surgery along with the meniscal repair. There were no intra-operative complications. The re-operation rate for meniscal repairs was 16.6% (11 cases) with 2 patients requiring further meniscal repairs and 9 patients underwent partial meniscectomies. The mean postoperative IKDC score was 88 (44-100), Tegner score was 7(2-10) and Lysholm score was 94 (57-100).
CONCLUSIONS: Our results showed that arthroscopic repair of meniscal tears in the paediatric population is an effective treatment option that has a low failure rate and good postoperative clinical with the advantage of preserving meniscal tissues.

OBJECTIVE: Meniscal wrapping is a fully arthroscopic technique that involves enhanced meniscal repair with a tissue-engineered collagen matrix wrapping. This study aims to investigate the feasibility of using the meniscal wrapping technique for the treatment of chronic or complex meniscal tears. The primary objective is to assess its failure rate. The secondary objectives are to analyse complication rate, functional outcomes and overall patient satisfaction.
METHODS: This retrospective case series study included patients who sustained chronic and complex tears undergoing meniscal wrapping with autologous liquid bone marrow injection. Failure rate was considered if the patient underwent partial or complete meniscectomy or knee replacement during the follow-up, while other unexpected knee reoperations were considered as complications. Clinical outcomes were evaluated through the IKDC score, Tegner Activity Score and Short Assessment of Patient Satisfaction.
RESULTS: Twenty-one patients were included (15 non-acute bucket-handle tears, three non-acute horizontal tears and three non-acute complex injuries). The failure rate was 9.5% at 33 months. The rate of other unplanned reoperations was 14.3%, but none of these complications were apparently directly related to the wrapping technique. The average postoperative IKDC was 73.3/100. No statistically significant difference was encountered between preinjury and postoperative Tegner Activity Score. The mean overall patient satisfaction was 88.3/100.
CONCLUSIONS: Meniscal wrapping can be safely used as an adjunctive technique to meniscal repair in such difficult-to-treat cases to preserve the meniscus. The technique achieves a low failure rate and promising results of knee function, and patient satisfaction.

Investigate meniscal extracellular matrix degradation. Equine menisci (n = 34 from 17 horses) were studied. Site-matched sections were cut and scored from three regions (ROIs; n = 102) and stained for histology, proteoglycan (safranin O and fast green), aggrecan, and collagen cleavage (NITEGE, DIPEN, and C1,2C antibodies, respectively). Picrosirius red and second harmonic generation microscopy were performed to investigate collagen ultrastructure. A total of 42 ROIs met the inclusion criteria and were included in the final analysis. The median (range) ROI histological score was 3 (0-9), providing a large spectrum of pathology. The median (range) proteoglycan score was 1 (0-3), representing superficial and central meniscal loss. The median (range) of DIPEN, NITEGE, and C1,2C scores was 1 (0-3), revealing immunostaining of the femoral and tibial surfaces. The proteoglycan scores exhibited significant positive associations with both histologic evaluation (p = 0.03) and DIPEN scores (p = 0.02). Additionally, a robust positive association (p = 0.007) was observed between the two aggrecanolysis indicators, NITEGE and DIPEN scores. A negative association (p = 0.008) was identified between NITEGE and histological scores. The C1,2C scores were not associated with any other scores. Picrosirius red and second harmonic generation microscopy (SHGM) illustrated the loss of the collagen matrix and structure centrally. Proteoglycan and collagen degradation commonly occur superficially in menisci and less frequently centrally. The identification of central meniscal proteoglycan and collagen degradation provides novel insight into central meniscal degeneration. However, further research is needed to elucidate the etiology and sequence of degradative events.

BACKGROUND: Tibial plateau fractures (TPFs) are usually associated with ligamentous or meniscal injuries that could remain misdiagnosed. An appropriate and early recognition may change the surgical management of these soft tissue injuries (STIs) that could be addressed concomitantly with TPF treatment. Magnetic resonance imaging (MRI) is an efficient diagnostic test to identify all associated STIs in TPFs. This study aims to analyze the MRI impact in identifying and guiding the STIs treatment in TPFs.
METHODS: This retrospective study included a consecutive series of 57 patients with TPFs treated between January 1st, 2022, and December 31st, 2022. All fracture patterns were classified according to the AO/OTA and Schatzker classification. The prevalence of STIs, including medial meniscus (MM), lateral meniscus (LM), anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL) injuries, was assessed through the MRI evaluation.
RESULTS: A statistical significance was found regarding the MRI detection of LM, ACL, PCL and MCL injuries that led to additional surgical procedures at the same time as the TPFs treatment (p < 0.05). In contrast, the amount of additional MM and LCL injuries identified by MRI, which resulted in other surgical procedures, was not statistically significant (p > 0.05).
CONCLUSIONS: Preoperative MRI has been demonstrated to be an effective procedure for diagnosing STIs in TPFs, significantly influencing and changing the surgical treatment.
METHODS: IV.

UNASSIGNED: To investigate the construction of a novel tissue engineered meniscus scaffold based on low temperature deposition three-dimenisonal (3D) printing technology and evaluate its biocompatibility.
UNASSIGNED: The fresh pig meniscus was decellularized by improved physicochemical method to obtain decellularized meniscus matrix homogenate. Gross observation, HE staining, and DAPI staining were used to observe the decellularization effect. Toluidine blue staining, safranin O staining, and sirius red staining were used to evaluate the retention of mucopolysaccharide and collagen. Then, the decellularized meniscus matrix bioink was prepared, and the new tissue engineered meniscus scaffold was prepared by low temperature deposition 3D printing technology. Scanning electron microscopy was used to observe the microstructure. After co-culture with adipose-derived stem cells, the cell compatibility of the scaffolds was observed by cell counting kit 8 (CCK-8), and the cell activity and morphology were observed by dead/live cell staining and cytoskeleton staining. The inflammatory cell infiltration and degradation of the scaffolds were evaluated by subcutaneous experiment in rats.
UNASSIGNED: The decellularized meniscus matrix homogenate appeared as a transparent gel. DAPI and histological staining showed that the immunogenic nucleic acids were effectively removed and the active components of mucopolysaccharide and collagen were remained. The new tissue engineered meniscus scaffolds was constructed by low temperature deposition 3D printing technology and it had macroporous-microporous microstructures under scanning electron microscopy. CCK-8 test showed that the scaffolds had good cell compatibility. Dead/live cell staining showed that the scaffold could effectively maintain cell viability (>90%). Cytoskeleton staining showed that the scaffolds were benefit for cell adhesion and spreading. After 1 week of subcutaneous implantation of the scaffolds in rats, there was a mild inflammatory response, but no significant inflammatory response was observed after 3 weeks, and the scaffolds gradually degraded.
UNASSIGNED: The novel tissue engineered meniscus scaffold constructed by low temperature deposition 3D printing technology has a graded macroporous-microporous microstructure and good cytocompatibility, which is conducive to cell adhesion and growth, laying the foundation for the in vivo research of tissue engineered meniscus scaffolds in the next step.
UNASSIGNED: 基于低温沉积3D打印技术构建新型组织工程半月板支架，评价该支架理化性质及生物相容性。.
UNASSIGNED: 取新鲜猪膝关节半月板，采用改良物理化学联合方法脱细胞处理，获得脱细胞半月板基质匀浆；经大体观察、HE及DAPI染色观察脱细胞效果，甲苯胺蓝、番红O及天狼猩红染色评估黏多糖和胶原保留情况。然后制备脱细胞半月板基质生物墨水，通过低温沉积3D打印技术制备新型组织工程半月板支架。扫描电镜观察微观结构；与脂肪来源干细胞共培养后，采用细胞计数试剂盒8（cell counting kit 8，CCK-8）检测支架细胞相容性，死/活细胞染色和细胞骨架染色观察细胞活性和形态；植入大鼠皮下后组织学染色评估支架炎症细胞浸润与降解情况。.
UNASSIGNED: 脱细胞处理后半月板基质匀浆呈透明凝胶状，DAPI和组织学染色示免疫原性的核酸去除，同时黏多糖及胶原成分保留。采用低温沉积3D打印技术成功构建新型组织工程半月板支架，扫描电镜示支架呈分级大孔-微孔的微观结构；CCK-8检测示支架具有良好细胞相容性；死/活细胞染色示支架可有效维持细胞活性（>90%）；细胞骨架染色示支架有利于细胞黏附和铺展；支架植入大鼠皮下1周后有轻度炎症反应，3周后未见明显炎症反应，并可见支架逐步降解。.
UNASSIGNED: 基于低温沉积3D打印技术构建的新型组织工程半月板支架具有分级大孔-微孔的微观结构和良好细胞相容性，有利于细胞黏附和生长，为下一步体内研究奠定基础。.

BACKGROUND: Mechanical unloading of the knee articular cartilage results in cartilage matrix atrophy, signifying the osteoarthritic-inductive potential of mechanical unloading. In contrast, mechanical loading stimulates cartilage matrix production. However, little is known about the response of meniscal fibrocartilage, a major mechanical load-bearing tissue of the knee joint, and its functional matrix-forming fibrochondrocytes to mechanical unloading events.
METHODS: In this study, primary meniscus fibrochondrocytes isolated from the inner avascular region of human menisci from both male and female donors were seeded into porous collagen scaffolds to generate 3D meniscus models. These models were subjected to both normal gravity and mechanical unloading via simulated microgravity (SMG) for 7 days, with samples collected at various time points during the culture.
RESULTS: RNA sequencing unveiled significant transcriptome changes during the 7-day SMG culture, including the notable upregulation of key osteoarthritis markers such as COL10A1, MMP13, and SPP1, along with pathways related to inflammation and calcification. Crucially, sex-specific variations in transcriptional responses were observed. Meniscus models derived from female donors exhibited heightened cell proliferation activities, with the JUN protein involved in several potentially osteoarthritis-related signaling pathways. In contrast, meniscus models from male donors primarily regulated extracellular matrix components and matrix remodeling enzymes.
CONCLUSIONS: These findings advance our understanding of sex disparities in knee osteoarthritis by developing a novel in vitro model using cell-seeded meniscus constructs and simulated microgravity, revealing significant sex-specific molecular mechanisms and therapeutic targets.

Osteoarthritis (OA) is a disabling chronic disease involving the gradual degradation of joint structures causing pain and dysfunction. Magnetic resonance imaging (MRI) has been widely used as a non-invasive tool for assessing OA-related changes. While anatomical MRI is limited to the morphological assessment of the joint structures, quantitative MRI (qMRI) allows for the measurement of biophysical properties of the tissues at the molecular level. Quantitative MRI techniques have been employed to characterize tissues\' structural integrity, biochemical content, and mechanical properties. Their applications extend to studying degenerative alterations, early OA detection, and evaluating therapeutic intervention. This article is a review of qMRI techniques for musculoskeletal tissue evaluation, with a particular emphasis on articular cartilage. The goal is to describe the underlying mechanism and primary limitations of the qMRI parameters, their association with the tissue physiological properties and their potential in detecting tissue degeneration leading to the development of OA with a primary focus on basic and preclinical research studies. Additionally, the review highlights some clinical applications of qMRI, discussing the role of texture-based radiomics and machine learning in advancing OA research.

The meniscus plays a crucial role in the proper functioning of the knee joint, and when it becomes damaged, partial removal or replacement is necessary to restore proper function. Understanding the stress and deformation of the meniscus during various movements is essential for developing effective materials for meniscus repair. However, accurately estimating the contact mechanics of the knee joint can be challenging due to its complex shape and the dynamic changes it undergoes during movement. To address this issue, the open-source software SCONE can be used to establish a kinematics model that monitors the different states of the knee joint during human motion and obtains relevant gait kinematics data. To evaluate the stress and deformation of the meniscus during normal human movement, values of different states in the movement gait can be selected for finite element analysis (FEA) of the knee joint. This analysis enables researchers to assess changes in the meniscus. To evaluate meniscus damage, it is necessary to obtain changes in its mechanical behavior during abnormal movements. This information can serve as a reference for designing and optimizing the mechanical performance of materials used in meniscus repair and replacement.

Background: Bucket-handle meniscal tears are mostly treated arthroscopically. However, there is no clear evidence as to whether the time to surgery impacts the outcome and whether or not lesions should be treated urgently. Methods: Sixty patients were interviewed about the current status of their knee with a mean follow-up of 6.1 years (SD = 3.5). Forty-one patients underwent meniscus repair, and fifteen patients received partial resections. The primary outcome was the rate of reoperation after meniscus repair. Secondary outcomes were pain at rest and during exercise, return to sports, and Tegner and Lysholm scores. Results: The average time to surgery was 14.4 days, with no significant impact of surgical timing on the rate of reoperation. Furthermore, no significant differences were found in pain levels, return to sports, or Tegner and Lysholm scores based on the timing of surgery. Conclusions: In our cohort, the time to surgery was not a prognostic factor for the reoperation rate or postoperative outcome in repairing bucket-handle meniscal tears. Therefore, arthroscopic repair should not be performed in an emergency setting but conducted after careful planning by experienced arthroscopy surgeons. Regarding the return to sports, postoperative factors such as rehabilitation protocols or surgical techniques could be more important than the time to surgery.