Objective To study degradation of the antigen-extracted meniscus in PBS solution with no enzyme or with different enzymes. Methods Four types of enzymes (collagenase, hyaluronidase, trypsin, papain) were used to enzymolyze the antigen-extracted meniscus and the fresh meniscus for 3, 7, 15 and 30 days (37℃). The antigenextracted meniscus and the fresh meniscus were immersed in PBS solution (37℃) for 30 days. Weight loss measurement, UV spectrophotometry, and scanning electron microscopy (SEM) were used to characterize the degraded materials. Results The two types of the materials were remarkably digested under the enzymes, especially under trypsin. The degradation curves showed that the antigen-extracted meniscus was enzymolyzed less than the fresh meniscus. The degradation products were grouped as amino, peptide, and polyose by the analysis. Both of the materials could hardly behydrolyzed in PBS solution without the enzymes. The four different enzymes had different surface morphologies under the examination of SEM. Conclusion The antigen-extracted meniscus is enzymolyzed more slowly than the fresh meniscus in vitro, and the result can be used as a guideline to the further research.
Objective To compare biological characteristics between articular chondrocyte and meniscal fibrochondrocyte cultured in vitro andto investigate the possibility of using cultured cartilage as a substitute for meniscus.Methods Chondrocytes isolated from articular cartilage and meniscus of rabbits aged 3 weeks were respectively passaged in monolayer and cultured in centrifuge tube. Cartilages cultured in centrifuge tube and meniscus of rabbit aged 6 weeks were detected by histological examination and transmission electron microscopy. Growth curves of articular chondrocytes and meniscalfibrochondrocytes were compared; meanwhile, cell cycles of articular chondrocytes and meniscal fibrochondrocytes in passage 2and 4 were separately measured by flow cytometry.Results Articular chondrocytes in passage 4 were dedifferentiated. Articular chondrocytes formed cartilage 2 weeks after cultivation in centrifuge tube, but meniscal fibrochondrocytes could not generate cartilage. The differences in ultrastructure and histology obviously existed between cultured cartilage and meniscus; moreover, apoptosis of chondrocytes appeared in cultured cartilage. Proportion of subdiploid cells in articular chondrocytes passage 2 and 4 was markedly higher than that in passage 2 and 4 fibrochondrocytes(Plt;0.05). Conclusion Meniscal fibrochondrocytes can not form cartilage after cultivationin centrifuge tube, while cartilage cultured in centrifuge tube from articular chondrocytes can not be used as graft material for meniscus. Articular cartilage ismarkedly different from meniscus.
ObjectiveTo manufacture a polycaprolactone (PCL)/type Ⅰ collagen (COL Ⅰ) tissue engineered meniscus scaffold (hereinafter referred to as PCL/COL Ⅰ meniscus scaffold) by three-dimensional (3D) printing with low temperature deposition technique and to study its physicochemical properties.MethodsFirst, the 15% PCL/4% COLⅠ composite solution and 15% PCL simple solution were prepared. Then, 15% PCL/4% COL Ⅰmeniscus scaffold and 15% PCL meniscal scaffold were prepared by using 3D printing with low temperature deposition techniques. The morphology and microstructure of the scaffolds were observed by gross observation and scanning electron microscope. The compression modulus and tensile modulus of the scaffolds were measured by biomechanical test. The components of the scaffolds were analyzed by Fourier transform infrared spectroscopy (FTIR). The contact angle of the scaffold surface was measured. The meniscus cells of rabbits were cultured with the two scaffold extracts and scaffolds, respectively. After cultured, the cell proliferations were detected by cell counting kit 8 (CCK-8), and the normal cultured cells were used as controls. Cell adhesion and growth of scaffold-cell complex were observed by scanning electron microscope.ResultsAccording to the gross and scanning electron microscope observations, two scaffolds had orientated 3D microstructures and pores, but the surface of the PCL/COLⅠ meniscus scaffold was rougher than the PCL meniscus scaffold. Biomechanical analysis showed that the tensile modulus and compression modulus of the PCL/COL Ⅰ meniscus scaffold were not significantly different from those of the PCL meniscus scaffold (P>0.05). FTIR analysis results showed that COL Ⅰ and PCL were successful mixed in PCL/ COL Ⅰ meniscus scaffolds. The contact angle of PCL/COLⅠ meniscus scaffold [(83.19±7.49)°] was significantly lower than that of PCL meniscus scaffold [(111.13±5.70)°] (t=6.638, P=0.000). The results of the CCK-8 assay indicated that with time, the number of cells cultured in two scaffold extracts showed an increasing trend, and there was no significant difference when compared with the control group (P>0.05). Scanning electron microscope observation showed that the cells attached on the PCL/ COL Ⅰ meniscus scaffold more than that on the PCL scaffold.ConclusionPCL/COLⅠmeniscus scaffolds are prepared by 3D printing with low temperature deposition technique, which has excellent physicochemical properties without cytotoxicity. PCL/COLⅠmeniscus scaffold is expected to be used as the material for meniscus tissue engineering.
Objective To summarize the current research progress on the concept, clinical presentation, diagnosis, biomechanical changes, and pathological mechanisms of the medial meniscus posterior root tear (MMPRT), and its clinical correlations with tibial rotation. MethodsThe research literature on MMPRT and its relationship with tibial rotation at home and abroad in recent years was extensively consulted and summarized. Results MMPRT is a specific and common type of medial meniscus injury of the knee joint. The occurrence of posterior medial pumping pain events following low-energy trauma in patients provides important clues for the diagnosis of this injury, with MRI being the preferred imaging modality. The biomechanical effects generated by MMPRT are similar to those caused by total removal of the medial meniscus. And this injury is usually associated with tibial rotation. MMPRT induces pathological external rotation of the tibia, which can be restored by timely medial meniscus posterior root repair. Furthermore, changes in tibial rotation are related to the healing status after medial meniscus posterior root repair. ConclusionMMPRT is closely related to tibial rotation. Understanding the biomechanics, pathological mechanisms, and clinical correlations between the two is of great significance for improving the diagnosis and treatment strategies.
Objective To examine the research status and predict trends in ME research findings from 1997-2023 on a global scale. Methods Web of Science Core Collection database was searched for original articles on ME published between 1997 and 2023, and then analyzed using CiteSpace, VOSviewer and the Online Analysis Platform of Literature Metrology to map scientific knowledge. Results A total of 748 articles were eventually included. The number of ME publications increased year by year, with the USA being the most productive country. Osteoarthritis, MRI, medial meniscus posterior root repair, biomechanical evaluation, lateral meniscus allograft transplantation, radiographic joint space narrowing are the high frequency keywords in co-occurrence cluster analysis and cocited reference cluster analysis. Medial meniscus posterior root tear and lateral meniscus allograft transplantation are current and evolving research hotspots in citation burst detection analysis. Conclusions The understanding of ME has been improved significantly during the past decades. Current research focuses on optimizing surgical repair methods and obtaining long-term follow-up outcomes for medial meniscal posterior root repair and developing methods to reduce ME after lateral meniscal allograft, as well as they are the highlights of future research on ME.
ObjectiveTo discuss the MRI diagnostic criteria, classification and lesion characteristics of medial discoid meniscus of the knee. MethodsWe retrospectively analyzed the clinical data of all patients who accepted MRI examination of knee from November 2009 to March 2015.Twenty-six of them (28 knees) with medial discoid meniscus were screened out.We measured and analyzed in all cases the ratio of the width of meniscus to that of tibial plateau on coronal slice, and the thickest thickness of the meniscus posterior horn on sagittal slice.All cases were divided into complete and incomplete type according to MRI findings, and then we compared the lesion rate of the two types of medial discoid meniscus. ResultsTwenty-eight cases were divided into complete type (n=16) and incomplete type (n=12);there were 17 cases of medial discoid meniscal tears, with a lesion rate of 60.7%.The ratio of the width of meniscus to that of tibial plateau on coronal slice was 0.29±0.06, and the thickest thickness of the meniscus posterior horn was (5.31±0.92) mm.The lesion rate of complete type was 81.2%, and 33.3% of the incomplete type.The lesion rate of the complete type was higher than that of the incomplete type, and the difference was statistically significant (P < 0.05). ConclusionsThree MRI diagnostic criteria for medial discoid meniscus are 3 or more than 3 consecutive layers discoid meniscus "tie-like" change in sagittal slice, the ratio of the width of meniscus to that of tibial plateau≥0.20, and the thickest thickness of the meniscus posterior horn≥4.40 mm.Medial discoid meniscuses are divided into complete and incomplete type; the lesion rate of complete type of medial discoid meniscus is higher than that of the incomplete type.
Objective To review the research progress of meniscus repair in recent years, in order to provide help for the clinical decision-making of meniscus injury treatment. Methods The domestic and foreign literature related to meniscal repair in recent years was extensively reviewed to summarize the reasons for the prevalence of meniscal repair, surgical indications, various repair methods and long-term effectiveness, the need to deal with mechanical structural abnormalities, biological enhancement repair technology, rehabilitation treatment, and so on. Results In order to delay the occurrence of osteoarthritis, the best treatment of meniscus has undergone an important change from partial meniscectomy to meniscal repair, and the indications for meniscal repair have been expanding. The mid- and long-term effectiveness of different meniscal repair methods are ideal. During meniscus repair, the abnormality of lower limb force line and meniscus protrusion should be corrected at the same time. There are controversies about the biological enhancement technology to promote meniscus healing and rehabilitation programs, which need further study. ConclusionMeniscal repair can restore the normal mechanical conduction of lower limbs and reduce the incidence of traumatic osteoarthritis, but the poor blood supply and healing ability of meniscal tissue bring difficulties to meniscal repair. Further development of new biological enhanced repair technology and individualized rehabilitation program and verification of its effectiveness will be an important research direction.
Objective To summarize the clinical features, surgical methods, and prognosis of bucket-handle meniscal tears (BHMTs), and provide guidance for clinical treatment. Methods The clinical data of 91 BHMTs patients (91 knees), who met the selection criteria and were admitted between January 2015 and January 2021, was retrospectively analyzed. There were 68 males and 23 females. Age ranged from 16 to 58 years with an average of 34.4 years. The injury was caused by sports in 68 cases, traffic accident in 15 cases, and falls or sprains in 8 cases. There were 49 cases of left knee injury and 42 cases of right knee injury. The time from the onset of symptoms to the admission ranged from 1 day to 13 months (median, 18 days), including >1 month in 35 cases and ≤1 month in 56 cases. Medial BHMTs occurred in 52 cases and lateral BHMTs in 39 cases. There were 36 cases with ACL rupture and 12 cases with discoid meniscus. The knee extension was limited more than 10° in 55 cases. According to the condition of meniscus injury, the meniscus suture with Inside-out combined with All-inside techniques (54 cases) or meniscoplasty (37 cases) under arthroscopy were selected. ACL reconstruction was performed in all patients with ACL rupture with autogenous hamstring tendon. Postoperative complications were observed. International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score were used to evaluate knee function, and clinical failure was recorded. Results Two patients developed intermuscular venous thrombosis, which improved after oral anticoagulant therapy. No vascular injury, postoperative infection, joint stiffness, or other complications occurred in all patients. All patients were followed up 24-95 months, with a median of 64 months. A total of 12 cases (13.19%) failed the operation and were re-operated or given oral anti-inflammatory analgesics and rehabilitation therapy. At last follow-up, IKDC score and Lysholm score of 91 patients significantly increased when compared with those before operation (P<0.05), while Tegner score significantly decreased (P<0.05). The above indexes of patients treated with meniscus suture and meniscoplasty were also significantly different from those before operation (P<0.05). ConclusionBHMTs occurs mostly in young men and is one of the important reasons for the limitation of knee extension after trauma. Arthroscopic meniscus suture and meniscoplasty can obtain good effectiveness according to individual conditions of patients. But the latter can better preserve the shape and function of meniscus, and theoretically can obtain better long-term outcomes, which needs to be confirmed by further research with larger sample size.
ObjectiveTo compare the mid-term effectiveness of arthroscopy versus conservative treatment on symptomatic discoid lateral meniscus (SDLM) in middle-aged and elderly patients. Methods The clinical data of 118 middle-aged and elderly patients (154 knees) with SDLM who received arthroscopy or conservative treatment between June 2014 and May 2016 were retrospectively analyzed, including 76 patients (96 knees) in the arthroscopy group (group A) and 42 patients (58 knees) in the conservative treatment group (group B). There was no significant difference in age, gender, and body mass index between the two groups (P>0.05). Compared with group B, the symptoms duration in group A was longer, the incidences of discoid lateral meniscus injury and mechanical symptoms were higher, and the visual analogue scale (VAS) score and Lysholm score before treatment were worse, with significant differences (P<0.05). VAS score and Lysholm score before and after treatment were recorded and compared. ResultsThe patients in both groups were followed up 60-74 months, with an average of 66.3 months. The follow-up time of group A and group B was (65.9±3.5) months and (67.0±4.0) months respectively, with no significant difference (t=–1.615, P=0.109). At last follow-up, in either group A or group B, the VAS score and Lysholm score significantly improved when compared with those before treatment (P<0.05). The differences of VAS score and Lysholm score in group A before and after treatment were significantly better than those in group B (P<0.05). ConclusionArthroscopy and conservative treatment have a satisfactory mid-term effectiveness on SDLM in middle-aged and elderly patients. However, the improvement of symptoms and function of arthroscopy was significantly better than that of conservative treatment. For middle-aged and elderly SDLM patients with invalidated conventional treatment for 6 months, severe clinical symptoms, long duration of symptoms, and combined with mechanical symptoms, arthroscopy should be given priority even if they are complicated with early osteoarthritis.
Objective To evaluate the clinical diagnostic value of knee MRI at 90° flexed position for Ramp lesions of medial meniscus. Methods A total of 228 patients with knee pain as the main complaint who were admitted between September 2021 and September 2023 was selected as the research subjects, of which 51 patients met the selection criteria and were enrolled in the study. There were 31 males and 20 females with an average age of 38.6 years (range, 15-67 years). Body mass index was 17.2-28.7 kg/m2 (mean, 23.9 kg/m2). There were 25 cases of left knee and 36 cases of right knee. The time from injury to admission was 0.1-14.3 weeks (mean, 2.1 weeks). Preoperative knee MRI at fully extended position (knee extension position) and 90° flexed position (knee flexion position) were performed to determine the presence of irregular signs at the posterior edge of the medial meniscus, and PHMM fluid high signal [i.e. complete fluid filling between the posterior horn of the medial meniscus (PHMM) and the capsule margin]. Findings obtained under arthroscopy served as the “gold standard” to analyze the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of MRI at knee extension and flexion positions for the two specific signs of Ramp lesion.Results Twenty-one patients (41.2%) were diagnosed with Ramp lesions by using arthroscopy, including 1 case of Thaunat type Ⅰ, 2 cases of type Ⅱ, 6 cases of type Ⅲ, 7 cases of type Ⅳ, and 5 cases of type Ⅴ. The positive rates of irregular signs at the posterior edge of the medial meniscus on MRI at knee extension and flexion positions were significantly different from the diagnosis of Ramp injury under arthroscopy (P<0.05). The sensitivity, specificity, accuracy, PPV, and NPV of MRI in the diagnosis of irregular signs were 76.1%, 60.0%, 66.7%, 57.1%, and 78.3% respectively at knee extension position, and 85.7%, 73.3%, 78.4%, 69.2%, and 88.0% respectively at knee flexion position. The positive rates of PHMM fluid high signal on MRI at knee extension and flexion positions were significantly different from the diagnosis of Ramp injury under arthroscopy (P<0.05). The sensitivity, specificity, accuracy, PPV, and NPV of MRI in diagnosing PHMM fluid high signal were 38.1%, 100%, 74.5%, 100%, and 69.8% respectively at knee extension position, and 85.7%, 100%, 94.1%, 100%, and 90.9% respectively at knee flexion position. ConclusionKnee MRI at 90° flexed position improves the diagnostic performance of the detection of medial meniscal Ramp lesions compared with MRI at fully extended position.