X-Shaped Knot Fixation and Double Posteromedial Portals for the Treatment of Posterior Cruciate Ligament Tibial Avulsion Fractures With Retention of the Posterior Septum.

Posterior cruciate ligament (PCL) avulsion fractures at the tibial attachment site are managed using various techniques. Some surgeries involve internal fixation with an adjustable double-loop plate, anterior-to-posterior suture suspension fixation, hollow lag screw fixation, and steel wire fixation. In this case, an X-shaped knot and double posteromedial portals are used to retain the posterior septum for fixation. In this technique, we describe double posteromedial portals are used in this method. The internal joint is fixed with an X-shaped knot, and the external joint is fixed with SwiveLock, which puts the wire belt binding PCL compression bone block in a perfect tension state. This surgical technique can achieve a sound functional reduction.

A modified anatomical posterior cruciate ligament reconstruction technique using the posterior septum and posterior capsule as landmarks to position the low tibial tunnel.

BACKGROUND: Lowering the exit position of the tibial tunnel can improve the clinical efficacy of posterior cruciate ligament (PCL) reconstruction, however, there is no unified positioning standard. This study aimed to use novel soft tissue landmarks to create a low tunnel. METHODS: A total of 14 human cadaveric knees and 12 patients with PCL injury were included in this study. Firstly, we observed the anatomical position between the PCL, posterior septum, and other tissue, and evaluated the relationship between the center of the low tibial tunnel (SP tunnel) and posterior septum and distal reflection of posterior capsule, and using computed tomography (CT) to evaluate distance between the center of the SP tunnel with bony landmarks. Then, evaluated the blood vessels content in the posterior septum with HE staining. Finally, observed the posterior septum and distal reflection of the posterior capsule under arthroscopy to explore the clinical feasibility of creating a low tibial tunnel, and assessed the risk of surgery by using ultrasound to detect the distance between the popliteal artery and the posterior edge of tibial plateau bone cortex. RESULTS: In all 14 cadaveric specimens, the PCL tibial insertions were located completely within the posterior medial compartment of the knee. The distance between the center of the SP tunnel and the the articular surface of tibial plateau was 9.4 ± 0.4 mm. All SP tunnels retained an intact posterior wall, which was 1.6 ± 0.3 mm from the distal reflection of the posterior capsule. The distances between the center of the SP tunnel and the the articular surface of tibial plateau, the champagne glass drop-off were 9.2 ± 0.4 mm (ICC: 0.932, 95%CI 0.806-0.978) and 1.5 ± 0.2 mm (ICC:0.925, 95%CI 0.788-0.975) in CT image. Compared with the posterior capsule, the posterior septum contained more vascular structures. Last, all 12 patients successfully established low tibial tunnels under arthroscopy, and the distance between the posterior edge of tibial plateau bone cortex and the popliteal artery was 7.8 ± 0.3, 9.4 ± 0.4 and 7.4 ± 0.3 mm at 30°, 60° and 90° flexion angels after filling with water and supporting with shaver in posterior-medial compartment of knee joint. CONCLUSIONS: A modified low tibial tunnel could be established in the PCL anatomical footprint by using the posterior septum and posterior capsule as landmarks.

Osteoarthritis related epigenetic variations in miRNA expression and DNA methylation.

Osteoarthritis (OA) is chronic arthritis characterized by articular cartilage degradation. However, a comprehensive regulatory network for OA-related microRNAs and DNA methylation modifications has yet to be established. Thus, we aimed to identify epigenetic changes in microRNAs and DNA methylation and establish the regulatory network between miRNAs and DNA methylation. The mRNA, miRNA, and DNA methylation expression profiles of healthy or osteoarthritis articular cartilage samples were downloaded from Gene Expression Omnibus (GEO) database, including GSE169077, GSE175961, and GSE162484. The differentially expressed genes (DEGs), differentially expressed miRNAs (DEMs), and differentially methylated genes (DMGs) were analyzed by the online tool GEO2R. DAVID and STRING databases were applied for functional enrichment analysis and protein-protein interaction (PPI) network. Potential therapeutic compounds for the treatment of OA were identified by Connectivity map (CMap) analysis. A total of 1424 up-regulated DEGs, 1558 down-regulated DEGs, 5 DEMs with high expression, 6 DEMs with low expression, 1436 hypermethylated genes, and 455 hypomethylated genes were selected. A total of 136 up-regulated and 65 downregulated genes were identified by overlapping DEGs and DEMs predicted target genes which were enriched in apoptosis and circadian rhythm. A total of 39 hypomethylated and 117 hypermethylated genes were obtained by overlapping DEGs and DMGs, which were associated with ECM receptor interactions and cellular metabolic processes, cell connectivity, and transcription. Moreover, The PPI network showed COL5A1, COL6A1, LAMA4, T3GAL6A, and TP53 were the most connective proteins. After overlapping of DEGs, DMGs and DEMs predicted targeted genes, 4 up-regulated genes and 11 down-regulated genes were enriched in the Axon guidance pathway. The top ten genes ranked by PPI network connectivity degree in the up-regulated and downregulated overlapping genes of DEGs and DMGs were further analyzed by the CMap database, and nine chemicals were predicted as potential drugs for the treatment of OA. In conclusion, TP53, COL5A1, COL6A1, LAMA4, and ST3GAL6 may play important roles in OA genesis and development.

Intra-articular Injection of Mesenchymal Stem Cells After High Tibial Osteotomy: A Systematic Review and Meta-analysis.

Background: Multiple studies have investigated the use of mesenchymal stem cells (MSCs) for patients undergoing high tibial osteotomy (HTO), and the effectiveness thereof remains controversial. Purpose: To analyze the effectiveness of intra-articular MSC injection in patients who underwent HTO in terms of clinical outcomes, radiological outcomes, and cartilage repair by a meta-analysis of the available literature. Study Design: Systematic review; Level of evidence, 3. Methods: The electronic databases of PubMed, Embase, Web of Science, and the Cochrane Library were searched from their inception to October 30, 2021, for comparative studies between patients who underwent HTO with and without intra-articular injection of MSCs, according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Study quality was assessed by the Coleman Methodology Score (CMS). Data with comparable results were pooled for meta-analysis. The primary outcomes of interest were the Hospital for Special Surgery (HSS), International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS), and Lysholm scores, as well as the International Cartilage Regeneration & Joint Preservation Society (ICRS) grade of cartilage repair. Radiological outcomes including femorotibial angle, posterior tibial slope, and hip-knee-ankle (HKA) angle were included as secondary outcomes. A fixed-model effect was used for meta-analyses with low heterogeneity between studies (I 2 < 25%), while the random-model effect was used for medium- to high-heterogeneity analyses (I 2 ≥ 25%). Results: A total of 843 studies were screened, of which 6 studies with 452 patients met the inclusion criteria and were included. The mean CMS was 81.17. Patients with MSC injection had significantly higher Lysholm scores (P = .007) and HSS scores (P = .01) and higher proportions of ICRS grade 1 (P = .03) and grade 2 (P = .02) cartilage repair in the medial femoral condyle and grade 2 cartilage repair in the tibial plateau (P = .04). There were no significant differences between groups in the IKDC score, KOOS Pain and Symptoms subscales, femorotibial angle, posterior tibial slope, or HKA angle. Conclusion: Intra-articular MSC injection may enhance the cartilage repair for patients who undergo HTO. However, evidence of improvement in knee functions remains limited. Registration: CRD42021291345 (PROSPERO).