Congruency Effects on Load Bearing in Diarthrodial Joints

Modelling load bearing in diarthrodial joints is challenging, due to the complexity of the materials, the boundary and interface conditions and the geometry. The articulating surfaces are covered with cartilage layers that are filled with a fluid that plays a major role in load bearing [Mow, V.C., Holmes, M.H., Lai, W.M. (1984) “Survey article: fluid transport and mechanical properties of articular cartilage: a review”, Journal of Biomechanics 17(5), 377–394]. Researchers have tended to approximate joint geometry using axisymmetry [Donzelli, P.S., Spilker, R.L., Ateshian, G.A., Mow, V.C. (1999) “Contact analysis of biphasic transversely isotropic cartilage layers and correlations with tissue failure”, Journal of Biomechanics 32, 1037–1047], often with a rounded upper articulating surface, creating a form of Hertz problem [Donzelli, P.S., Spilker, R.L., Ateshian, G.A., Mow, V.C. (1999) “Contact analysis of biphasic transversely isotropic cartilage layers and correlations with tissue failure”, Journal of Biomechanics 32, 1037–1047]. However, diarthrodial joints (shoulder, hip and knee) are equipped with peripheral structures (glenoid labrum, acetabular labrum and meniscus, respectively) that tend to deepen the joint contact and thus cause initial contact to be established at the periphery of the joint rather than “centrally”. The surface geometries are purposefully incongruent, and the incongruency has a significant effect on the stresses, pressures and pressure gradients inside the tissue. The models show the importance of the peripheral structures and the incongruency from a load-bearing perspective. Joint shapes must provide a compromise between demands for load-bearing, lubrication and the supply of nutrients to the chondrocytes of the cartilage and cells of the peripheral structures. Retention and repair of the functionality of these peripheral structures should be a prime consideration in any surgical treatment of an injured joint.     

Quantitative proteomic analysis of eight cartilaginous tissues reveals characteristic differences as well as similarities between subgroups

Human synovial joints display a characteristic anatomic distribution of arthritis, e.g. rheumatoid arthritis primarily affects the metacarpophalangeal and proximal finger joints, but rarely the distal finger joints, whereas osteoarthritis occurs in the distal and proximal finger joints. Pelvospondylitis has a selective localization to the spine and sacroiliac joints. Is this tropism due to differences between the cartilages at the molecular level? To substantiate this concept the present study provides a background detailed compositional analysis by relative quantification of extracellular matrix proteins in articular cartilages, meniscus, intervertebral disc, rib, and tracheal cartilages on samples from 5–6 different individuals using an optimized approach for proteomics. Tissue extraction followed by trypsin digestion and two-dimensional LC separations coupled to tandem mass spectrometry, relative quantification with isobaric labeling, iTRAQ^TM, was used to compare the relative abundance of about 150 proteins. There were clear differences in protein patterns between different kinds of cartilages. Matrilin-1 and epiphycan were specific for rib and trachea, whereas asporin was particularly abundant in the meniscus. Interestingly, lubricin was prominent in the intervertebral disc, especially in the nucleus pulposus. Fibromodulin and lumican showed distributions that were mirror images of one other. Analyses of the insoluble residues from guanidine extraction revealed that a fraction of several proteins remained unextracted, e.g. asporin, CILP, and COMP, indicating cross-linking. Distinct differences in protein patterns may relate to different tissue mechanical properties, and to the intriguing tropism in different patterns of joint pathology.     

An in vitro model to assess mechanisms and efficacy of a cellular conduit for treatment of avascular meniscal injuries

Tears in the avascular portion of the knee meniscus are commonplace and are frequently incapable of healing spontaneously. Delivery of synovial cells from the meniscal periphery to avascular injuries can result in an effective healing response but is difficult to accomplish surgically. This report describes the development of a novel in vitro model comprised of three-dimensionally cultured cells in agarose used to assess the proof of concept that a cellular conduit device could be used to facilitate the delivery of synovial fibroblasts from a cell source to a remote acellular recipient site. The results indicate that synovial fibroblasts are capable of migrating through a cellular conduit more optimally than a created trephined channel over a clinically relevant distance in response to a chemotactic gradient. This model proved to be a reliable way to assess fibroblast-like synoviocyte migration in a clinically relevant fashion for application to avascular meniscal tear healing methodologies, and provided mechanistic information regarding the successful in vivo testing of this specific biomedical device.     

Before the transition? The final middle Palaeolithic lithic industry from the Grotte du Renne (layer XI) at Arcy-sur-Cure (Burgundy,France)

The Grotte du Renne at Arcy-sur-Cure (Burgundy, France) has yielded remains from several occupation layers, extending from the end of the middle Palaeolithic to the upper Palaeolithic. The last Mousterian layer (XI), which precedes the Châtelperronian occupations (layers Xa, Xb, Xc, IX, VIII), was previously interpreted as a precursor of the transition complex. The new study of the lithic assemblage of layer XI, in the context of the other final Mousterian occupations in Arcy (Grotte du Bison, Galerie Schoepflin Rotonde, Grotte de l’Hyène) challenges this hypothesis. The Mousterian Arcy complex can be divided into three main techno-complexes: Levallois–Charentian, Discoid–Denticulate and Levallois Mousterian. We observed a rupture between the final Mousterian and Châtelperronian industries as regards all the aspects of the technical system; production methods, blank management, tool types, and some changes in raw material composition.     

Systemic hypoxia alters gene expression levels of structural proteins and growth factors in knee joint cartilage

We investigated the effects of short- (8- and 24-h) and long-term (3 weeks) exposure to systemic normobaric hypoxia (13%) on the gene expression level of structural proteins and growth factors in knee joint cartilage of rabbits. Collagen type Ia2, II, and Va1, TGF-beta1, and b-FGF were upregulated after short-term hypoxia in both menisci, but not in articular cartilage. In contrast, long-term hypoxia downregulated gene expression level of collagens, aggrecan, and growth factors in articular cartilage and meniscal fibrocartilage. Interestingly, gene expression levels of non-collagenous proteins biglycan, decorin, and versican were not affected by short-term or by long-term hypoxia in knee joint cartilage. The present study suggests that changes in oxygen level differentially affect gene expression levels of growth factors, collagens, and non-collagenous proteins in normal knee joint cartilage in rabbits.     

关节镜下不同术式治疗盘状半月板的临床疗效研究

目的:比较分析关节镜下不同术式治疗盘状半月板的临床效果。方法:选取盘状半月板患者85例,其中完全型盘状半月板47例,行完全切除术(A组)23例,行部分切除成形术(B组)24例;不完全性盘状半月板38例,行完全切除术(C组)20例,行部分切除成形术(D组)18例。术后随访观察,膝关节功能评价分别采用国际膝关节文献委员会膝关节评估表(the international knee documentation committee knee evaluation form,IKDC)和Lysholm评分进行。结果:78例患者均得到有效随访。随访时间12-18个月,平均(16.2±3.4)月。术前各组各评分均无显著差异(P0.05)。完全型盘状半月板中,A组术后IKDC和Lysholm评分分别为(92.9±9.7)分、(93.4±8.6)分,优良率为91.3%(21/23),均显著优于B组[(83.5±8.4)分、(82.7±9.2)分、70.8%(17/24)](P0.05)。C组和D组术后各指标比较无显著差异(P0.05)。结论:关节镜下不同术式治疗盘状半月板均可获得较为满意的疗效,但对于完全型盘状半月板而言,采取完全切除术治疗的患者较部分切除成形术者术后疗效具有一定优势。     

术后疼痛对膝关节盘状半月板损伤患者膝关节功能、生活质量及心理状态的影响及其危险因素的Logistic回归分析

摘要 目的：探讨术后疼痛对膝关节盘状半月板损伤患者膝关节功能、生活质量及心理状态的影响及其危险因素的Logistic回归分析。方法：选取2019年5月～2022年1月福建医科大学附属第一医院收治的膝关节盘状半月板损伤患者120例,均行关节镜手术治疗,观察并评价所有患者手术疗效;根据术后6个月膝关节是否疼痛分为疼痛组（n=16）与无痛组（n=104）。比较两组术前及术后6个月Lysholm膝关节功能评分、健康调查简表（SF-36）评分、焦虑自评量表（SAS）和抑郁自评量表（SDS）评分。单因素及多因素Logistic回归分析术后疼痛的危险因素。结果：120例膝关节盘状半月板损伤患者术前、术后3个月、术后6个月Lysholm评分分别为（56.97±8.62）分、（78.09±10.53）分、（89.26±8.14）分,术后3个月、术后6个月Lysholm评分均显著高于术前（均P＜0.001）。临床疗效显示行关节镜手术后优良率为86.67%（104/120）。术后6个月两组Lysholm评分、SF-36评分均高于手术前,但疼痛组低于无痛组（P＜0.05）;术后6个月两组SAS评分、SDS评分均低于手术前,但疼痛组高于无痛组（P＜0.05）。单因素分析发现,年龄、BMI、撕裂类型、滑膜切除、术后冷敷、开始负重时间与术后痛疼有关（P＜0.05）;而性别、受教育程度、吸烟史、饮酒史、ASA分级、患侧、病程、损伤部位、手术方式与术后痛疼无关（P＞0.05）。多因素Logistic回归分析显示,年龄、BMI≥24 kg/m²、纵裂或其他撕裂、滑膜切除、开始负重时间＜4周及术后6个月SAS评分、SDS评分是术后疼痛的独立危险因素,而术后冷敷是术后疼痛的保护因素（P＜0.05）。结论：术后疼痛对膝关节盘状半月板损伤患者膝关节功能、生活质量及心理状态产生明显负面影响。年龄、BMI≥24 kg/m²、混合性撕裂、滑膜切除、开始负重时间＜4周以及术后6个月SAS评分、SDS评分是术后疼痛危险因素,而术后冷敷是其保护因素,临床可据此施以针对性防治措施。     

Mechanical injury of explants from the articulating surface of the inner meniscus

Knee osteoarthritis is accelerated by damage to the meniscus, a fibrocartilage tissue that assists in load transmission. However, little is known about the mechanical or cellular response of the meniscus to injurious overloading. Here, in vitro studies explored injury to meniscal explants using a compressive overloading protocol that has been well characterized for articular cartilage. Cartilage samples were processed in parallel as a reference to the extensive literature on cartilage injury. Injured meniscal explants showed extensive cell death at the articulating surface but no gross tissue damage, while similar conditions of peak stress and strain resulted in cartilage surface fissures and cell death consistent with moderate overloading. Post-injury gene expression in meniscal explants indicated a decrease in seven of the nine catabolic and pro-inflammatory molecules surveyed, while cartilage experienced a downregulation in ADAMTS-5 and TNF-α only. These data demonstrated a resiliency of the meniscus to injury, and that an acute increase in catabolic activities is not necessarily a consequence of mechanical overloading.     

Mesenchymal stem cells for enhancing biological healing after meniscal injuries

The meniscus is a semilunar fibrocartilage structure that plays important roles in maintaining normal knee biomechanics and function. The roles of the meniscus, including load distribution, force transmission, shock absorption, joint stability, lubrication, and proprioception, have been well established. Injury to the meniscus can disrupt overall joint stability and cause various symptoms including pain, swelling, giving-way, and locking. Unless treated properly, it can lead to early degeneration of the knee joint. Because meniscal injuries remain a significant challenge due to its low intrinsic healing potential, most notably in avascular and aneural inner two-thirds of the area, more efficient repair methods are needed. Mesenchymal stem cells (MSCs) have been investigated for their therapeutic potential in vitro and in vivo. Thus far, the application of MSCs, including bone marrow-derived, synovium-derived, and adipose-derived MSCs, has shown promising results in preclinical studies in different animal models. These preclinical studies could be categorized into intra-articular injection and tissue-engineered construct application according to delivery method. Despite promising results in preclinical studies, there is still a lack of clinical evidence. This review describes the basic knowledge, current treatment, and recent studies regarding the application of MSCs in treating meniscal injuries. Future directions for MSC-based approaches to enhance meniscal healing are suggested.     

Relationship between meniscal degeneration and element contents

The purpose of this study is to investigate the relationship between meniscal degeneration and element contents. The contents of elements (calcium, phosphorus, sulfur, and magnesium) in the menisci from 17 patients with osteoarthritis (OA) of the knee, 6 with rheumatoid arthritis (RA), and 2 who underwent the surgical operation for malignant tumors (control) were analyzed by inductively coupled plasma-atomic emission spectrometry, and the menisci were divided into four stages (Stage 0–3) of histological degeneration. The calcium contents of the menisci were 0.26±0.16 in Stage 0, 0.50±0.37 in Stage 1, and 0.69±0.66 in Stage 2, respectively (the values represent mg elements/g dry tissue). They increased with the progression of the stage. This tendency was found in the menisci with OA, but was not clear in those with RA. The calcium content in the control group was 0.17±0.09 mg/g. There was no significant relationship between the stage of degeneration and the contents of phosphorus, sulfur, or magnesium. The calcium content of the meniscus might indicate the degree of meniscal degeneration.