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 review the details of the current effortsto reconstruct or replace the meniscus.Methods Three kinds of proceduresof reconstructing or replacing the meniscus were analyzed and evaluated by an extensive review of the latest literatures concerned. Results Three kinds of techniques were established to reconstruct the meniscus clinically, i.e., the allograft of the meniscus, meniscal reconstruction with the autotendon, and the meniscus scaffold. There were still a few defects in the meniscal replacement, and so the curative techniques would still be investigated. Conclusion Many efforts have been made to reconstruct the meniscus after its injury or its resection so as to prevent degeneration of the knee joint. The meniscal replacement has been employed for many years, but it has not worked so well. The establishment of an ideal replacement of the meniscus requires further studies. Therefore, reconstruction of the meniscus function is still a challenging problem to the surgeons concerned.
ObjectiveTo evaluate the effectiveness of arthroscopically assisted treatment of posterior cruciate ligament (PCL) tibial eminence avulsion fractures associated with meniscus posterior horn tear. MethodsBetween January 2012 and December 2014, 21 patients with PCL avulsion fracture and meniscus posterior horn tear were arthroscopically treated with polyester suture and hollow screw fixation. There were 10 males (10 knees) and 11 females (11 knees), aged 14-53 years (mean, 35.7 years). The causes included sport injury in 11 cases, traffic accident injury in 9 cases, and daily life injury in 1 case. Based on the anteroposterior and lateral X-ray films, CT, and MRI, PCL avulsion fractures were diagnosed, and 2 cases had anterior cruciate ligament avulsion fractures. The results of posterior drawer test were positive in all patients, with no end point in 14 cases and with soft end point in 7 cases; all patients showed tibial sink. The preoperative International Knee Documentation Committee (IKDC) score and Lysholm score were 46.5±5.5 and 43.3±4.5 respectively. The time from injury to operation was 6-22 days (mean, 10 days). ResultsThe operation time was 60-100 minutes (mean, 75 minutes). Primary healing of incision was obtained in all patients, without no complication of infection. The mean follow-up time was 27.4 months (range, 12-46 months). The results of posterior drawer test were negative in 19 cases, and positive in 2 cases (having hard end point). Tibial sink disappeared. At last follow-up, X-ray film showed good healing of fracture, and no displacement. The patients had no locking knee, snapping or tenderness of joint space, and the Mcmurray sign was negative; the IKDC score and Lysholm score were significantly improved to 92.0±2.5 and 92.7±2.6 respectively (t=-39.903, P=0.000; t=-43.242, P=0.000). The range of motion was normal in 20 patients (0-130°) except 1 patient having limited flexion (0-80°), whose range of motion returned to 0-120° after release. ConclusionThe arthroscopic fixation technique has satisfactory results for the reduction and fixation of PCL avulsion fracture associated with meniscus posterior horn tear because of easy operation, firm fixation, and economic price.
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.
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.
OBJECTIVE To investigate the effect of meniscus suture on meniscus healing which included healing time and healing pattern. METHODS Fourty healthy rabbits were adopted in this study. The model of meniscus injury was made by a longitudinal incision at the medial meniscus of the left knee. The rabbits were divided into two groups, the experimental group was treated by meniscus suture and the control group was unsutured. After operation, the meniscus samples were collected periodically and observed by gross, light and electronic microscope to analysis the meniscus healing. RESULTS The injured meniscus was healed gradually and completely at the sixth week in the experimental groups. More fibroblasts and less fibrocartilage cells could be observed in the healed meniscus. Oppositely, there was no meniscus healing in the control group and the edge of injured meniscus was sealed by epithelioid cells. CONCLUSION The meniscus suture can accelerate the healing process of meniscus injury. Besides, early suture make the injured meniscus correctly positioned to ensure the normal healing process.
Objective To elucidate the latest research progress and application of tissue engineered meniscus. Methods The literature concerning the advance in tissue engineered meniscus was extensively reviewed, then closely-related issues including seed cells, scaffolds, and bioreactors were analyzed. Results With more and more attention being paid to meniscus tissue engineering, different approaches and strategies for seed cells, scaffolds, and bioreactors have contributed to the generation of meniscal constructs, which are capable of restoring meniscal lesions to some extent, but translating successes in basic science research to clinical application is still limited. Conclusion More research for the optimal combination of the appropriate cell source, the scaffold type, and the proper physical and chemical factors for the stimulation of cells differentiation into tissue with optimal phenotypes in tissue engineered meniscus is still in needed, but the overall future looks promising.
Objective To investigate the result of the arthroscopicrepair of the meniscus tears with the absorbable sutures. Methods From June 1998 to May2003，the meniscus tears in 110 patients (78 males, 32 females; aged 1466 years, averaged 27.5 years) were repaired with absorbable sutures under an arthroscope. In the patients, there were 93 vertical split injuries, 12 transverse split injuries, and 5 hidden split injuries. There were 78 tears in the lateral margin of the meniscus, 23 tears in the anterior angle of the meniscus, and 9 tears in the posterior angle of the meniscus. Ninetyone patients had 2 sutures, 13 patients had 4 sutures, 4 patients had 6 sutures, and 2 patients had 8 sutures. The rehabilitation program was performed in all the patients postoperatively, and the clinical outcome was observed. The Lysholm score was 57±12 preoperatively. Results Thefollow-up for an average of 26 months (range,12-67 months) showed that 3 patients had a light pain on exertion in the surgically-treated knee;1 patientunderwent an operation again for recurrence of the symptoms due to a failure in the healing of the meniscus tear, so a second arthroscopic operation was performed; and the other patients had a satisfactory result with an excellent knee function. The Lysholm score was 92±7 after operation. Conclusion The arthroscopic repair of the meniscustears has advantages of safety and reliability in the suturing and easier to perform. The repaired meniscus can play much better physiological and biomechanical functions, and will not limit the normal movement of the meniscus during the knee flexion after the sutures are absorbed.
ObjectiveTo investigate the effects of meniscectomy and transplantation repair of the knee on the stress area and average pressure of the tibiofemoral articular surface so as to provide a reference for the relevant basic and clinical researches. MethodsSeven qualified right knee joints from adult men cadavers were selected. Required structure was retained after careful dissection. The pressure-sensitive paper was clipped to the proper size in accordance with the measured size of the tibial platform to reserve. The experiment was divided into 4 groups: normal knee group (group A), knee meniscus injury group (group B), knee meniscectomy group (group C), and knee meniscus transplantation group (group D). A horizontal incision above the meniscus was made in the position of knee joint capsule, and the pressure-sensitive paper was placed into the medial and lateral space of the knee joint, then the proximal tibia and distal femur were fixed stably and finally a universal mechanical machine was used for testing in appropriate environmental conditions (the knee joints were given longitudinal 700 N pressure at 0° extension and 30, 60, 90, and 120° flexion for continuous 120 seconds) until the full color reaction. The knee models were prepared, and then the universal mechanical machine was used to perform a test according to the method stated above respectively. The pressure-sensitive paper was removed, and the color negative films were separated and marked. Colorful image analysis system was used to calculate and analyze the stress area and average pressure after the scanner being used to collect image information. ResultsThe stress area was gradually reduced and the average pressure was gradually increased with increasing flexion angle of the knee. There was significant difference in the stress area and the average pressure between various flexion angles in 4 groups (P<0.05). Group C had significantly lower stress area and significantly higher average pressure than the other 3 groups (P<0.05), but no significant difference was found among groups A, B, and D (P>0.05). ConclusionThe stress of the tibiofemoral articular surface significantly increases after knee meniscus injury or resection, and the average pressure significantly increases. The stress of the tibiofemoral articular surface can be restored to almost normal after meniscus transplantation. Therefore, the injured meniscus should also be retained or repaired in the static state.
Objective To investigate the effects of the insulin-like growth factor 1 (IGF-1), the transforming growth factor β1(TGFβ1), and the basic fibroblast growth factor (bFGF) on proliferation and cell phenotype of the human fetal meniscal cells, and to find out the best combination and concentration of the growth factors for the meniscus tissue engineering. Methods The fetus came from the healthy woman accidental abortion and the procedure had got her approval.The human fetal meniscal fibrochondrocytes were cultured in vitro. The cell phenotype was identifiedby the collagen type Ⅱ immunohistochemistry and Aggrecan immunofluorescence. Inthe growth factor groups, the 3rd passage meniscal cells synchronized by the serum starvation method and were mixed with IGF-1 (1, 10, 50, 100 μg/L), TGF-β1 (0.1, 1.0, 5.0, 10.0, 50.0 μg/L), and bFGF (5, 10, 50, 100, 200 μg/L), respectively, and in the combination groups, the combinations of bFGF and TGF-β1, bFGF and IGF-1, TGF-β1 and IGF-1 were established at their optimal effect concentrations. The control group was also established for comparison. The dose-response relationship was studied at 48 h and 72 h bythe MTT colorimetric method. Results The 3rd passage meniscalcells could express collagen type Ⅱ and Aggrecan before and after the addition of the three growth factors. The proliferating effects of the growth factors (IGF-1 50 μg/L，TGF-β1 5 μg/L，bFGF 50 μg/L) on the 3rd passage cells at 48 h and 72 h were significantly better in the growth factor groups than in the control group (Plt;0.05)，and the combination groups of bFGF 50 μg/L and IGF-1 50 μg/L, IGF-1 50 μg/L and TGF-β1 5 μg/L showed a significantly higher proliferatingeffect than that in the single growth factor group (Plt;0.05). bFGF 50 μg/L and TGF-β1 5 μg/L had no synergetic effect (Pgt;0.05). Conclusion IGF-1, TGF-β1 and bFGF can promote the proliferation of the human fetal meniscal cells, respectively, and the combinations of bFGF and IGF-1, IGF-1 and TGF-β1 at their optimal concentrations can have better proliferating effects than the single growth factor. They can be used for the in vitro amplification of the meniscal seed cells.