Bioinspired gradient scaffolds for osteochondral tissue engineering.

Repairing articular osteochondral defects present considerable challenges in self-repair due to the complex tissue structure and low proliferation of chondrocytes. Conventional clinical therapies have not shown significant efficacy, including microfracture, autologous/allograft osteochondral transplantation, and cell-based techniques. Therefore, tissue engineering has been widely explored in repairing osteochondral defects by leveraging the natural regenerative potential of biomaterials to control cell functions. However, osteochondral tissue is a gradient structure with a smooth transition from the cartilage to subchondral bone, involving changes in chondrocyte morphologies and phenotypes, extracellular matrix components, collagen type and orientation, and cytokines. Bioinspired scaffolds have been developed by simulating gradient characteristics in heterogeneous tissues, such as the pores, components, and osteochondrogenesis-inducing factors, to satisfy the anisotropic features of osteochondral matrices. Bioinspired gradient scaffolds repair osteochondral defects by altering the microenvironments of cell growth to induce osteochondrogenesis and promote the formation of osteochondral interfaces compared with homogeneous scaffolds. This review outlines the meaningful strategies for repairing osteochondral defects by tissue engineering based on gradient scaffolds and predicts the pros and cons of prospective translation into clinical practice.

[Quantitative study of 3.0T MRI on the thickness of knee joint cartilage in healthy young people].

OBJECTIVE: To explore 3.0T MRI accurate measurement of knee cartilage thickness in healthy youth provides reliable anatomical parameters for quantitative diagnosis of osteoarthritis and accurate osteotomy of joint replacement. METHODS: From January 2013 to December 2013, 30 healthy young volunteers including 14 males and 16 females with an average age of (25.8±2.4) years old ranging from 22 to 33 years were recruited in Changchun, Jilin Province, and a 3.0T MRI scan was performed on the bilateral knee joints of each volunteer. The cartilage thickness was measured on the lateral femoral condyle (LFC), medial femoral condyle (MFC), lateral tibial plateau (LTP) and medial tibial plateau (MTP). RESULTS: In four regions of the knee joint:LFC, MFC, LTP and MTP, whether young men or women, there was no significant difference in cartilage thickness between the left and right knee joints (P>0.05). There were significant differences in knee cartilage thickness between healthy young men and women (P<0.05). In the same sex group, LFC cartilage thickness was thinner in the middle, thicker in front and rear;MFC cartilage thickness was the thinnest in front and gradually thickening from the front to the rear; LTP cartilage thickness was thickest in the middle, second in the rear and thinnest in the front;MTP cartilage thickness was the thinnest in the front, was relatively uniform in the middle and rear and thicker than that in the front. CONCLUSION: In Northeast China, among healthy adults aged 22 to 33, gender difference may be an important factor in the difference of cartilage thickness in various regions of the knee joint. Regardless of whether male or female healthy young people, the cartilage thickness of the entire knee joint is unevenly distributed, but there is no significant difference in cartilage thickness in the same area between the left and right knee joints.

Bilateral anterior congenital radial head dislocation in adults: a case report and literature review.

Objective: Congenital dislocation of the radial head (CRHD) is a rare condition, with bilateral anterior cases being even less common worldwide. Only a few cases had residual pain after adulthood, even when left untreated. Herein, we describe an adult case of bilateral anterior CRHD with significant pain and snapping during motion. The aim of this study was to report the physical and radiological findings, treatment methods, and short-term outcomes of our case and to review adult CRHD cases in the literature. Patient: A 21-year-old male patient presented to our hospital with chief complaints of snapping and exacerbated pain during motion in his left elbow. Diagnoses and interventions: Detailed medical history and physical examination results were recorded. Radiographic examinations were performed on the bilateral elbow, and the diagnosis of bilateral anterior congenital radial head dislocation was confirmed. To relieve the pain and snapping in the left elbow, we performed open reduction and fixation of the radial head with annular ligament reconstruction and ulnar osteotomy. Postoperatively, the elbow rested at 90° flexion with a cast for 16 weeks, and the K-wire was removed on the 10th week; afterward, active functional exercises were performed. Outcomes: The patient was followed-up for 1 year. The pain in his left elbow was relieved with a reduction in the visual analog scale score from 7 to 3. The range of motion of the left elbow was changed from 0° to 135° (preoperative) to -5° to 120° (postoperative) (extension-flexion) without any snapping. However, restrictions in external rotation have not yet been fully resolved. Further physical rehabilitation is required. Conclusion: When managing patients with congenital radial head dislocation, the contralateral elbow should be evaluated to identify potential bilateral cases. Surgical options should be discussed with adult patients only for the strong need for functional improvement, although the outcomes may not be fully satisfactory.

Nucleic acid nanoassembly-enhanced RNA therapeutics and diagnosis.

RNAs are involved in the crucial processes of disease progression and have emerged as powerful therapeutic targets and diagnostic biomarkers. However, efficient delivery of therapeutic RNA to the targeted location and precise detection of RNA markers remains challenging. Recently, more and more attention has been paid to applying nucleic acid nanoassemblies in diagnosing and treating. Due to the flexibility and deformability of nucleic acids, the nanoassemblies could be fabricated with different shapes and structures. With hybridization, nucleic acid nanoassemblies, including DNA and RNA nanostructures, can be applied to enhance RNA therapeutics and diagnosis. This review briefly introduces the construction and properties of different nucleic acid nanoassemblies and their applications for RNA therapy and diagnosis and makes further prospects for their development.

Natural biopolymer scaffold for meniscus tissue engineering.

Meniscal injuries caused by trauma, degeneration, osteoarthritis, or other diseases always result in severe joint pain and motor dysfunction. Due to the unique anatomy of the human meniscus, the damaged meniscus lacks the ability to repair itself. Moreover, current clinical treatments for meniscal injuries, including meniscal suturing or resection, have significant limitations and drawbacks. With developments in tissue engineering, biopolymer scaffolds have shown promise in meniscal injury repair. They act as templates for tissue repair and regeneration, interacting with surrounding cells and providing structural support for newly formed meniscal tissue. Biomaterials offer tremendous advantages in terms of biocompatibility, bioactivity, and modifiable mechanical and degradation kinetics. In this study, the preparation and composition of meniscal biopolymer scaffolds, as well as their properties, are summarized. The current status of research and future research prospects for meniscal biopolymer scaffolds are reviewed in terms of collagen, silk, hyaluronic acid, chitosan, and extracellular matrix (ECM) materials. Overall, such a comprehensive summary provides constructive suggestions for the development of meniscal biopolymer scaffolds in tissue engineering.

Clinical efficacy of direct anterior approach vs. other surgical approaches for total hip arthroplasty: A systematic review and meta-analysis based on RCTs.

Background: Direct anterior approach (DAA) is an accurate technique for total hip arthroplasty (THA) through the muscle gap. Physicians who apply DAA believe that it accelerates patient recovery and results in lower rates of postoperative dislocation. However, the traditional surgical approach adherents believe that it is shorter and has fewer complications than DAA. Methods: We use the method of META analysis to organize and analyze the data of the randomized controlled studies (RCT) obtained after our screening. To compare the clinical efficacy of DAA approach and other surgical approaches for THA. Results: After rigorous screening, 15 RCT studies were included in our study, and data were extracted. The study included 1,450 patients from 15 RCTs, with a mean age of 63 years and a distribution of 52-67 years. Six weeks after the operation, the Harris hip score of the DAA approach improved by an average of 4.06 points (95% confidence interval (CI) 2.54 -5.59, P < 0.01, I 2 = 45%, which can significantly improve the clinical efficacy of patients. However, the 0.61 points [95% confidence interval (CI) -1.13 -2.34, P > 0.01, I 2 = 0%] at 3 months and 1.49 points [95% confidence interval (CI) -1.65 -2.25, P > 0.01, I 2 = 0%] at 12 months postoperatively. In terms of dislocation rate, results show that the use of DAAs does not reduce Dislocation Rate with significant statistical heterogeneity among study groups (95% CI 0.18-2.94 P > 0.001, I 2 = 0%). Conclusion: The hip function of DAA was superior to posterolateral approach (PLA) and latera approach (LA) in the early days after hip replacement, especially within six weeks. However, at six months or more after surgery, the difference was not significant. The DAA did not show a lower rate of dislocation than other surgical approaches. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO.

Bionic biphasic composite scaffolds with osteochondrogenic factors for regeneration of full-thickness osteochondral defects.

Full-thickness osteochondral defects lack the capability to self-repair owing to their complicated hierarchical structure. At present, clinical treatments including microfracture etc. have shown some efficacy; however, the newborn tissue exhibits some drawbacks, such as fibrocartilage formation and insufficient mechanical properties, eventually leading to osteoarthritis. Moreover, cartilage and bone tissues have different biological characteristics. Therefore, the simultaneous repair of full-thickness osteochondral defects is highly challenging. To achieve optimal repair, we constructed a bionic biphasic composite scaffold with on-demand osteochondrogenic factors. Kartogenin and extractive mesenchymal stem cells were introduced into a mPEG-block-poly(L-valine) thermogel set as the upper layer to accelerate cartilage repair. A poly(lactide-co-glycolide)/hydroxyapatite porous scaffold was immobilized with bone morphogenetic protein-2 as the bottom layer to facilitate subchondral repair. The intermediate interface, being a combination of the two layers, was expected to reconstruct the calcification zone. Gross evaluation, micro-computed tomography, and magnetic resonance imaging indicated that at 6 months after implantation, the scaffold encapsulating mesenchymal stem cells and osteochondrogenic factors had a better effect compared with other groups. More importantly, the composition of the new cartilage and bone was confirmed by western blotting, H&E staining, immunohistochemistry, and immunofluorescence. Taken together, this bionic composite scaffold with osteochondrogenic factors offers a promising option for the repair of full-thickness osteochondral defects.

Osteomyelitis variolosa, an issue inherited from the past: case report and systematic review.

BACKGROUND: Osteomyelitis variolosa is a self-limiting disease triggered by variola virus that cannot be prevented or repaired. Smallpox has been eradicated for 40 years, and complications that remain after smallpox has been cured have become a remarkable diagnostic challenge for contemporary physicians. In this systematic review, we searched PubMed (MEDLINE), Web of Science, and Google Scholar for cases on complications, diagnosis, and treatment for osteomyelitis variolosa between January 1980 and February 2021. RESULTS: Ten papers and eleven finished cases, all patients from India, were included for comparison with the present case. In total, 100% of patients presented with bilateral elbow deformities, the ankle was the second most common site of lesion in 50%, and knee lesions accounted for 25% in this study. Flexion contracture, joint instability, secondary arthritis, and fracture are common complications of osteomyelitis variolosa, and most patients receive conservative treatment, while internal fixation has good results for combined fractures. CONCLUSIONS: Although osteomyelitis variolosa is not a direct threat to the safety of patients, severe skeletal deformities can have a significant impact on quality of life. With advances in surgical techniques, clinicians are offering an increasing number of treatment options for patients with osteomyelitis variolosa. However, most importantly, smallpox has basically been removed from the historical arena, and for areas where smallpox was once endemic, physicians need to deepen the understanding of this disease again.