Objective To study the effect of chitosan (CS) mediated insul in-l ike growth factor 1 gene (igf-1) transfection on the repair of articular cartilage defect. Methods Twelve 3-month-old healthy male rabbits weighting 2.0-2.5 kg were randomly divided into 2 primary groups, control and intervention groups (n=6 per group). Control group was further divided into normal control (left knee) and normal saline (NS) control (right knee) groups. While, intervention group was divided into CS (left knee) and CS/igf-1 intervention (right knee) groups. Cartilage defects were created in the knee joints except normalcontrol. Intra-articular injections of CS/igf-1 complex was administrated 2 times a week for 4 weeks in CS/igf-1 interventiongroup, 0.5 mL CS in CS intervention group, and 0.5 mL sal ine solution in normal control and sal ine control groups. At 28days after treatments, the cartilage samples were collected for histological observation and collagen type II and aggrecan mRNA evaluation. Results HE staining and toluidine blue staining revealed that CS/igf-1 and CS intervention could significantly stimulated cartilage regeneration accompanied with fibrosis and inflammatory cell infiltration, however, CS/igf-1 treatment resulted in the best repair of cartilage defect. In contrast, sal ine control group only showed fibrous tissue prol iferation and inflammatory cell infiltration without significant cartilage repairing. In terms of collagen type II and aggrecan gene expression, significant differences were observed in each pairwised comparison among 4 groups in the order of CS/igf-1 gt; CS gt; NS gt; normal control (P lt; 0.05). Conclusion In situ CS/ifg-1 complex transfection can enhance the formation of mesochondrium by upregulating collagen type II or aggrecan expression, which might enhance the repair of articular cartilage defect.
ObjectiveTo investigate the effectiveness of arthroscopic bipolar radiofrequency energy (bRFE) and lateral partial meniscectomy for lateral meniscus tear and cartilage lesion. MethodsBetween January 2011 and December 2012, 40 eligible patients with lateral meniscus tear and cartilage injury in the lateral knee compartment underwent arthroscopic treatment, and the clinical data were analysed retrospectively. There were 21 males and 19 females, aged 15-65 years (mean, 42.1 years). The left knee was involved in 22 cases and the right knee in 18 cases. The causes of injury included sport injuries in 5 cases and sprain of knee joints in 8 cases, the remaining patients had no history of trauma. The disease duration ranged from 1 month to 10 years (median, 10 months). The Lysholm score and Japanese Orthopaedic Association (JOA) score of the knee were 59.9±8.2 and 69.6±5.3. According to the Outerbridge classification, 2 cases were rated as grade I, 21 cases as grade II, 17 cases as grade III, and 10 cases as grade IV. The scores described by Noyes were 1-16 (mean, 6.52). The Noyes scores were from 1 to 6 points in 20 patients (group A) and 7 to 16 points in 20 patients (group B). During surgery, all patients underwent partial meniscectomy, and radiofrequency-based chondroplasty was used. Knee joint function was assessed using the Lysholm score and JOA score of the knee, and the clinical outcomes between different degrees of cartilage lesions were also compared. ResultsAll incisions healed primarily without complication. All the patients were followed up 8-31 months (mean, 18.1 months). The Lysholm and JOA scores of the knee at last follow-up (92.2±7.2 and 92.9±7.9, respectively) were significantly higher than those at preoperation (P<0.05). There was no significant difference in preoperative Lysholm and JOA scores of the knee between groups A and B (P>0.05), but significance difference was found between 2 groups at last follow-up (P<0.05). ConclusionArthroscopic bRFE and lateral partial meniscectomy have good effectiveness in treating lateral meniscus tear and cartilage lesion. The effectiveness is better in patients with mild cartilage lesion than in patients with severe cartilage lesion.
A novel structural dynamics test method and device were designed to test the biomechanical effects of dynamic axial loading on knee cartilage and meniscus. Firstly, the maximum acceleration signal-to-noise ratio of the experimental device was calculated by applying axial dynamic load to the experimental device under unloaded condition with different force hammers. Then the experimental samples were divided into non-specimen group (no specimen loaded), sham specimen group (loaded with polypropylene samples) and bovine knee joint specimen group (loaded with bovine knee joint samples) for testing. The test results show that the experimental device and method can provide stable axial dynamic load, and the experimental results have good repeatability. The final results confirm that the dynamic characteristics of experimental samples can be distinguished effectively by this device. The experimental method proposed in this study provides a new way to further study the biomechanical mechanism of knee joint structural response under axial dynamic load.