Updates in biological therapies for knee injuries: menisci

The preservation of meniscal tissue is paramount for long-term joint function, especially in younger patients who are athletically active. Many studies have reported encouraging results following the repair of meniscus tears, including both simple longitudinal tears located in the periphery and complex multiplanar tears that extend into the central third avascular region. However, most types of meniscal lesions are managed with a partial meniscectomy. Options to restore the meniscus range from an allograft transplantation to the use of synthetic and biological technologies. Recent studies have demonstrated good long-term outcomes with meniscal allograft transplantation, although the indications and techniques continue to evolve, and the long-term chondroprotective potential of this approach has yet to be determined. Several synthetic implants, most of which are approved in the European market, have shown some promise for replacing part of or the entire meniscus, including collagen meniscal implants, hydrogels, and polymer scaffolds. Currently, there is no ideal implant generated by means of tissue engineering. However, meniscus tissue engineering is a fast developing field that promises to develop an implant that mimics the histologic and biomechanical properties of a native meniscus.     

The Physiologic Basis of Surgery

Four methods of allograft tendon-to-muscle anastomosis were tested in single cycle distraction to failure using 10 anastomosed ovine calcaneal tendon-biceps brachii units. The tendon-muscle units were compared to intact ovine biceps brachii muscle units. Methods of tendon-to-muscle anastomosis were derived from modifications of existing muscle tendon repair and tenorrhaphy techniques. Load to failure (N), stiffness (N/cm), distraction (cm), and modes of failure were recorded. Of the four methods tested, the side-to-side technique demonstrated the highest load to failure (152.1 N), the greatest stiffness (17.6 N/cm), the least distraction (2.99 cm) before failure, and the least amount of muscle tissue trauma at failure. Results indicate that, of the methods tested, the side-to-side technique offers the greatest initial stability and should therefore allow adequate revascularization and healing of the anastomosis site.     

Human interleukin-10 gene inhibits acute rejection by triggering apoptosis in allograft vascular transplantation

The aim this study is to explore effect of IL-10 on apoptosis of VSMCs in allograft arterial transplantation rats, and to investigate mechanism. SD rats were divied into three groups, including control group (CN, with physiological saline), blank vector group (BV, with blank adenovirus) and combined gene group (CG, with adenovirus carried IL-10 gene). The isolated donor vascular was transfected with the adenovirus carried hIL-10 gene for 30 minutes by immersing method. Forty-five days post transplantation, the grafts were harvested. The allografts pathologioc changes were observed and the size of vascular intima and middle layer of allografts were measured. The expression of hIL-10 was detected by RT-PCR, ELISA and immunohistochemistry, respectively. The repression of Fas/Fasl in artery allografts was also examined by immunohistochemistry method. The results indicated that 45 days after transplantation, the intimal and middle hyperplasia ratio in CG group was significantly lower than that in CN and BV group (P < 0.05). The transgene expression of human interleukin-10 was significantly enhanced in CG group compared to CN and BV group by ELISA, RT-PCR and immunohistochemistry (P < 0.05). The expression of Fas/FasL was higher in CG group compared with the other groups (P < 0.05). The level of apoptotic smooth muscle cells were significantly increased in CG group compared to CN and BV group (P < 0.05). In conclusion, adenovirus mediated IL-10 expression could up-regulate Fas/FasL expression, induce smooth muscle cell apoptosis and alleviate angiosclerosis process. The IL-10 gene transfer to allograft artery could inhibit acute rejection reaction of allograft vascular transplantation.     

Bone bridge fixation has superior biomechanics on posterior knees to bone plug fixation after lateral meniscal allograft transplantation – A biomechanical study simulating partial weight-bearing conditions

BackgroundIt remains unknown how biomechanics change in posterior lateral knee using different fixation techniques in lateral meniscal allograft transplantation (MAT) during simulated toe-touch partial weight-bearing. This study aimed to compare the biomechanical effects on posterior knee between bridge and bone plug fixation in lateral MAT.MethodsIntact knee, bone bridge fixation, and bone plug fixation were tested with 500 N of axial load during knee flexion at 0°, 30°, and 60°, which simulated toe-touch partial weight-bearing. Contact area and peak pressure were assessed on posterior knee and the shift of peak pressure position were measured.ResultsOn the posterior lateral compartment, the contact mechanics of bone bridge fixation were similar to those of the intact knee (all P-values > 0.05), but its peak pressure was higher than that of intact knee at 60° (P = 0.002). For bone plug fixation, the contact area of the posterior lateral knee was significantly lower than those of intact knee and bone bridge fixation at 30° and 60° (all P-values < 0.05). The peak pressure of the posterior lateral knee was higher than that of the intact knee at all flexions and higher than that of bone bridge fixation at 30° and 60° (all P-values < 0.05). The peak pressure position of bone plug fixation shifted more laterally and posteriorly compared with intact knee and bone bridge fixation during knee flexion.ConclusionBone bridges could maintain posterior knee biomechanics better than bone plug fixation during knee bending during partial weight-bearing.     

锁定钢板联合异体腓骨与锁定钢板单独使用治疗肱骨近端骨折的Meta分析

文题释义：肱骨近端骨折：属于发生率较高的骨折，骨折位置在肱骨外科颈以远1.0-2.0 cm到肱骨头关节面之间，随着人口老龄化的加剧，肱骨近端骨折发生率呈上升的趋势，肱骨近端骨折的最佳治疗方式也存在争议。   锁定钢板联合异体腓骨：依次切开皮肤、组织，暴露肱骨近端，选择合适的异体腓骨插入髓腔，利用同种异体腓骨的支撑作用及克氏针的撬拨作用临时复位肱骨近端骨折处，之后采用合适大小的锁定钢板对骨折端进行固定。 背景：肱骨近端骨折的最佳治疗方式一直存在着争议，其中使用锁定钢板的开放复位内固定是治疗肱骨近端骨折的一种常用方法，近年有许多研究指出锁定钢板联合异体腓骨可以获得更好的刚性结构。 目的：系统评价锁定钢板联合异体腓骨与锁定钢板单独使用治疗肱骨近端骨折的临床疗效。 方法：截止至2020年1月，在中国知网、万方数据库、维普、PubMed、EMBASE、Cochrane Library等数据库收集锁定钢板与锁定钢板联合异体腓骨治疗肱骨近端骨折疗效对比的文献进行质量评价。采用国际Cochrane协作组提供的RevMan 5.0软件进行Meta分析，比较锁定钢板组与锁定钢板组联合异体腓骨组在美国肩肘外科医师学会评分、Constant评分、肱骨头高度丢失值、颈干角变化值、术后并发症总发生率、二次手术率、螺钉切出率及肱骨头坏死率方面的差异。结果与结论：①纳入8项研究，共623例患者；②结果显示，锁定钢板联合异体腓骨和单纯锁定钢板在术后随访末期美国肩肘外科医师学会评分(95%CI：4.29-6.84，P < 0.05)、Constant评分(95%CI：6.46-15.10，P < 0.05)、肱骨头高度丢失值(95%CI：-3.24至-2.07，P < 0.05)、颈干角变化值(95% CI：-7.20至-5.95，P < 0.05)、并发症总发生率(95%CI：0.18-0.51，P < 0.05)及螺钉切出率(95% CI：0.13-0.65，P < 0.05)等方面差异有显著性意义；③但2种方法在二次手术率(95%CI：0.13-1.14，P > 0.05)及肱骨头坏死率(95% CI：0.41-2.11，P > 0.05)等方面差异无显著性意义；④提示锁定钢板联合异体腓骨与单纯锁定钢板治疗肱骨近端骨折在美国肩肘外科医师学会评分、Constant评分、肱骨头高度丢失值、颈干角变化值、术后并发症发生率、螺钉切出率方面更具优势，但在二次手术率及肱骨头缺血性坏死方面没有明显差异。 ORCID: 0000-0003-2626-8833(涂冬鹏) 中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程     

Relationship between European Mitochondrial Haplogroups and Chronic Renal Allograft Rejection in Patients with Kidney Transplant

Mitochondrial DNA variants may contribute to differences in mitochondrial function, leading to an altered immune system. The aim of this study was to analyze the relationship between mtDNA haplogroups and the development of chronic allograft dysfunction in patients with kidney transplant. A retrospective observational study was carried out on 261 patients who received kidney transplant (114 had stable transplant and 147 patients developed chronic allograft dysfunction). DNA samples were genotyped for 14 mtDNA polymorphisms by using Sequenom''s MassARRAY platform (San Diego, CA, USA). Only European white patients within the N macro-cluster were included. Patients with haplogroups V (odds ratio (OR)=0.32; p=0.037) and J (OR=0.36; p=0.038) showed lower odds for developing CRAD than patients with haplogroup H. After adjusting for the most significant variables, haplogroups V and J tended to statistical significance (p=0.091 and p=0.067 respectively). This is a preliminary study in which mtDNA haplogroups seem to be implicated in susceptibility or protection for developing chronic allograft dysfunction.