Influence of proteoglycan contents and of tissue hydration on the frictional characteristics of articular cartilage

2005 ◽  
Vol 219 (3) ◽  
pp. 175-182 ◽  
Author(s):  
M H Naka ◽  
Y Morita ◽  
K Ikeuchi
Keyword(s):  
Articular Cartilage ◽  
Water Content ◽  
Articular Surface ◽  
Superficial Layer ◽  
Low Friction ◽  
Cartilage Surface ◽  
Intact Condition ◽  
Measured Water ◽  
Femoral Condyles

In this work, the hypothesis that water content and substances present on the articular surface play an important role in lubrication through the formation of a layer with a high content of water on the articular surface is analysed. The hydrophilic properties of proteoglycans exposed at the articular surface and hydration of tissue are the main responsible factors for the formation of this layer. The role of the articular surface in the frictional characteristics of articular cartilage was examined using specimens (femoral condyles of pigs) with intact and wiped surfaces tested in intermittent friction tests. Results indicated that the intact condition presented low friction in comparison with the wiped condition. The measured water loss of the articular cartilage after sliding and loading indicated a gradual decrease in the water content as the time evolved, and rehydration was observed after the submersion of unloaded specimens in the saline bath solution. Micrographic analyses indicated the presence of a layer covering the articular surface, and histological analyses indicated the presence of proteoglycans in this superficial layer. The hydration of the cartilage surface layer and proteoglycan in this layer influence lubrication.

scholarly journals Recent Advances in Understanding the Role of Cartilage Lubrication in Osteoarthritis

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6122
Author(s):  
Yumei Li ◽  
Zhongrun Yuan ◽  
Hui Yang ◽  
Haijian Zhong ◽  
Weijie Peng ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Essential Role ◽  
Daily Life ◽  
Early Stage ◽  
Joint Disease ◽  
Low Friction ◽  
Cartilage Surface ◽  
Wear And Tear ◽  
Lubrication Properties

The remarkable lubrication properties of normal articular cartilage play an essential role in daily life, providing almost frictionless movements of joints. Alterations of cartilage surface or degradation of biomacromolecules within synovial fluid increase the wear and tear of the cartilage and hence determining the onset of the most common joint disease, osteoarthritis (OA). The irreversible and progressive degradation of articular cartilage is the hallmark of OA. Considering the absence of effective options to treat OA, the mechanosensitivity of chondrocytes has captured attention. As the only embedded cells in cartilage, the metabolism of chondrocytes is essential in maintaining homeostasis of cartilage, which triggers motivations to understand what is behind the low friction of cartilage and develop biolubrication-based strategies to postpone or even possibly heal OA. This review firstly focuses on the mechanism of cartilage lubrication, particularly on boundary lubrication. Then the mechanotransduction (especially shear stress) of chondrocytes is discussed. The following summarizes the recent development of cartilage-inspired biolubricants to highlight the correlation between cartilage lubrication and OA. One might expect that the restoration of cartilage lubrication at the early stage of OA could potentially promote the regeneration of cartilage and reverse its pathology to cure OA.

scholarly journals The Role of Hyaluronic Acid in Cartilage Boundary Lubrication

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1606 ◽  
Author(s):  
Weifeng Lin ◽  
Zhang Liu ◽  
Nir Kampf ◽  
Jacob Klein
Keyword(s):  
Hyaluronic Acid ◽  
Synovial Fluid ◽  
Surface Force ◽  
Force Balance ◽  
New Paradigm ◽  
Low Friction ◽  
Cartilage Surface ◽  
Boundary Lubricant ◽  
Lipid Layers

Hydration lubrication has emerged as a new paradigm for lubrication in aqueous and biological media, accounting especially for the extremely low friction (friction coefficients down to 0.001) of articular cartilage lubrication in joints. Among the ensemble of molecules acting in the joint, phosphatidylcholine (PC) lipids have been proposed as the key molecules forming, in a complex with other molecules including hyaluronic acid (HA), a robust layer on the outer surface of the cartilage. HA, ubiquitous in synovial joints, is not in itself a good boundary lubricant, but binds the PC lipids at the cartilage surface; these, in turn, massively reduce the friction via hydration lubrication at their exposed, highly hydrated phosphocholine headgroups. An important unresolved issue in this scenario is why the free HA molecules in the synovial fluid do not suppress the lubricity by adsorbing simultaneously to the opposing lipid layers, i.e., forming an adhesive, dissipative bridge between them, as they slide past each other during joint articulation. To address this question, we directly examined the friction between two hydrogenated soy PC (HSPC) lipid layers (in the form of liposomes) immersed in HA solution or two palmitoyl–oleoyl PC (POPC) lipid layers across HA–POPC solution using a surface force balance (SFB). The results show, clearly and surprisingly, that HA addition does not affect the outstanding lubrication provided by the PC lipid layers. A possible mechanism indicated by our data that may account for this is that multiple lipid layers form on each cartilage surface, so that the slip plane may move from the midplane between the opposing surfaces, which is bridged by the HA, to an HA-free interface within a multilayer, where hydration lubrication is freely active. Another possibility suggested by our model experiments is that lipids in synovial fluid may complex with HA, thereby inhibiting the HA molecules from adhering to the lipids on the cartilage surfaces.

A Fibril Reinforced Poroelastic Model of Articular Cartilage Including Depth Dependent Material Properties

1999 ◽  
Author(s):  
L. P. Li ◽  
M. D. Buschmann ◽  
A. Shirazi-Adl
Keyword(s):  
Articular Cartilage ◽  
Regional Differences ◽  
Articular Surface ◽  
Collagen Fibrils ◽  
Superficial Zone ◽  
Cartilage Surface ◽  
Poroelastic Model ◽  
Oriented Parallel ◽  
Strain Dependent ◽  
Very High

Abstract Articular cartilage is a highly nonhomogeneous, anisotropic and multiphase biomaterial consisting of mainly collagen fibrils, proteoglycans and water. Noncalcified cartilage is morphologically divided into three zones along the depth, i.e. superficial, transitional and radial zones. The thickness, density and alignment of collagen fibrils vary from the superficial zone, where fibrils are oriented parallel to the articular surface, to the radial zone where fibrils are perpendicular to the boundary between bone, and cartilage. The concentration of proteoglycans increases with the depth from the cartilage surface. These regional differences have significant implications to the mechanical function of joints, which is to be explored theoretically in the present work by considering inhomogeneity along the cartilage depth. A nonlinear fibril reinforced poroelastic model is employed as per Li et al. (1999) in which the collagen fibrils were modeled as a distinct constituent whose tensile stiffness was taken to be very high and be strain dependent but whose compressive stiffness was neglected.

MICROSCOPIC TRIBOLOGICAL ANALYSIS OF THE KNEE JOINT

Tribologia ◽  
2018 ◽  
Vol 273 (3) ◽  
pp. 147-154
Author(s):  
Anna M. RYNIEWICZ ◽  
Andrzej RYNIEWICZ ◽  
Anna PUKALUK ◽  
Paweł PAŁKA
Keyword(s):  
Articular Cartilage ◽  
Synovial Fluid ◽  
Knee Joint ◽  
Superficial Layer ◽  
Ground Substance ◽  
Atomic Force ◽  
Electron Microscopes ◽  
Tribological Analysis ◽  
Scanning Electron Microscopes

The aim of the conducted research was the evaluation of the topography and the structure of the superficial layer of meniscus and articular cartilage. These are surfaces that optimise the friction and lubrication process in the knee joint. The animal samples of the menisci and the articular cartilage were examined. The research was performed using scanning electron microscopes and an atomic force microscope. The structure of the surface of meniscus and articular cartilage is very regular. The collagenous fibres, which are embedded in the ground substance, are parallel to the surface. The undulation of the surface was observed. In the area of the anterior horn on tibia side of both menisci as well as in the anterior area of tibial plateau, the concavity and convexity pattern is evident. The observed cavities enable the accumulation of the synovial fluid. The synovial fluid plays the role of the lubricant in the knee joint, and its presence is highly desired during the load transmission.

scholarly journals EGFR signaling is critical for maintaining the superficial layer of articular cartilage and preventing osteoarthritis initiation

2016 ◽  
Vol 113 (50) ◽  
pp. 14360-14365 ◽  
Author(s):  
Haoruo Jia ◽  
Xiaoyuan Ma ◽  
Wei Tong ◽  
Basak Doyran ◽  
Zeyang Sun ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
High Surface ◽  
Cartilage Degeneration ◽  
Superficial Layer ◽  
Joint Disease ◽  
Egfr Signaling ◽  
Superficial Zone ◽  
Cartilage Surface ◽  
Healthy Cartilage ◽  
Important Regulator

Osteoarthritis (OA) is the most common joint disease, characterized by progressive destruction of the articular cartilage. The surface of joint cartilage is the first defensive and affected site of OA, but our knowledge of genesis and homeostasis of this superficial zone is scarce. EGFR signaling is important for tissue homeostasis. Immunostaining revealed that its activity is mostly dominant in the superficial layer of healthy cartilage but greatly diminished when OA initiates. To evaluate the role of EGFR signaling in the articular cartilage, we studied a cartilage-specific Egfr-deficient (CKO) mouse model (Col2-Cre EgfrWa5/flox). These mice developed early cartilage degeneration at 6 mo of age. By 2 mo of age, although their gross cartilage morphology appears normal, CKO mice had a drastically reduced number of superficial chondrocytes and decreased lubricant secretion at the surface. Using superficial chondrocyte and cartilage explant cultures, we demonstrated that EGFR signaling is critical for maintaining the number and properties of superficial chondrocytes, promoting chondrogenic proteoglycan 4 (Prg4) expression, and stimulating the lubrication function of the cartilage surface. In addition, EGFR deficiency greatly disorganized collagen fibrils in articular cartilage and strikingly reduced cartilage surface modulus. After surgical induction of OA at 3 mo of age, CKO mice quickly developed the most severe OA phenotype, including a complete loss of cartilage, extremely high surface modulus, subchondral bone plate thickening, and elevated joint pain. Taken together, our studies establish EGFR signaling as an important regulator of the superficial layer during articular cartilage development and OA initiation.

Effect of Anisotropic Permeability of the Superficial Layer on the Frictional Property in Articular Cartilage

2013 ◽  
Author(s):  
Kyuichiro Imade ◽  
Hiromichi Fujie
Keyword(s):  
Articular Cartilage ◽  
Hydrodynamic Lubrication ◽  
Articular Surface ◽  
Compressive Strain ◽  
Electron Microscopic Observation ◽  
Superficial Layer ◽  
Frictional Property ◽  
Hydraulic Permeability ◽  
Electron Microscopic ◽  
Biphasic Model

Articular cartilage has a significant lubrication property that has been explained in previous studies by many theories including mixed lubrication, hydrodynamic lubrication, surface gel hydration lubrication, biphasic theory, and so on. However the mechanism of continuously low friction in articular cartilage still remains unclear. Reynaud and Quinn indicated that the hydraulic permeability was significantly anisotropic under compressive strain; the tangential permeability becomes lower than the normal permeability under compression [1]. Meanwhile scanning electron microscopic observation indicated that the superficial layer of articular surface was consisted of close-packed collagen fibers aligning parallel with articular surface and tangling each other in normal cartilage (Fig. 1). It is, therefore, suggested that the permeability is extremely low in the tangential direction when subjected to compressive strain. We have a hypothesis that the unique structure and properties in the articular cartilage superficial layer may improve the lubrication properties [2]. Therefore, we performed an analytical study using a fiber-reinforced poroelastic biphasic model to determine the effect of lateral permeability reduction in the superficial layer on the frictional property of articular cartilage.

scholarly journals Nanostructures of Phospholipids on Articular Cartilage Surface and their Functions

2021 ◽  
Vol 9 (3) ◽  
pp. 01-05
Author(s):  
Pawlak Pawlak ◽  
M. Sojka
Keyword(s):  
Contact Angle ◽  
Articular Cartilage ◽  
Lubrication Mechanism ◽  
Low Friction ◽  
Cartilage Surface ◽  
Hydration Layer ◽  
Articular Cartilage Surface ◽  
Intelligent Material

Phospholipids bilayers fulfill an important role in natural joint lamellar-repulsive lubrication mechanism. Low friction between surfaces coated with negatively charged the phospholipid headgroup (–PO4-) as being due to a hydration layer. Wettability of the cartilage surface depends on the number of PLs that act as a lubricant. The cartilage can be classified as a group of intelligent material, which in the wet state has a contact angle of ~0º, and the air-dry state has a contact angle of ~104º.

Treatment of Articular Cartilage Injuries in the Knee

2009 ◽  
Author(s):  
Tony Wanich
Keyword(s):  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Thin Layer ◽  
Subchondral Bone ◽  
Articular Surface ◽  
Low Friction ◽  
Cartilage Injuries ◽  
Articular Cartilage Injuries

Articular cartilage is a unique biphasic tissue composed of chondrocytes surrounded by extracellular matrix (ECM). This thin layer of tissue covers the articular surface of diarthroidal joints and provides a durable, low friction interface which also helps to reduce the load transmitted to the underlying subchondral bone.

scholarly journals Factors Contributing to Graft Matching in a Patellar Osteochondral Allograft Selection Model (211)

2021 ◽  
Vol 9 (10_suppl5) ◽  
pp. 2325967121S0032
Author(s):  
Hailey Huddleston ◽  
Theodore Wolfson ◽  
David Christian ◽  
Nozomu Inoue ◽  
Adam Yanke
Keyword(s):  
Articular Cartilage ◽  
Subchondral Bone ◽  
Point Cloud ◽  
Articular Surface ◽  
Osteochondral Allograft ◽  
Least Mean Square ◽  
Bone Surface ◽  
Cartilage Surface ◽  
Articular Cartilage Surface ◽  
Surface Models

Objectives: Patellar osteochondral allograft (OA) transplantation has been shown to be a successful treatment in patients with isolated patellar cartilage injury. Currently, there is minimal guidance in anatomic and sizing factors that portend similar patellar surface topography. The most commonly utilized patellar sizing criteria to match the donor and recipient is radiographic tibial width. Our hypothesis is that specific patella anatomic factors will better predict surface topography matching. To our knowledge, no prior study has investigated the topography of the patella and what intrinsic factors of the graft and the recipient affect matching of the chondral and osseous layers between the graft and defect. Methods: Computed tomography (CT) images of the specimens were acquired and three-dimensional (3D) CT models of the patella were then created and exported into point-cloud models using a 3D reconstruction software program. Circular articular cartilage and subchondral bone defect models were created in each point-cloud model of the recipient patella with a diameter of 18 mm and 22.5 mm at 3 locations: the medial, central, and lateral portions of the patellar surface. Circular articular cartilage and subchondral bone graft models were created on all possible locations on the articular cartilage surface models of the donor patellae (Figure 1). The graft models were virtually placed on the surface of the defect model. Orientation of the graft model was adjusted so that its axis matched that of the defect site. Least distances between the graft and the defect articular surface models were calculated and were defined as the shortest distance from the point in question to the corresponding point in space. A mean value of the least distances was calculated for each position of the graft model. The mean least distance of subchondral bone surface in each point was calculated simultaneously. The graft model was then rotated 360° around the axis perpendicular to the articular cartilage surface in 1° increments, and the least distance of articular cartilage surface and the resulting least distance of subchondral bone surface were calculated at each rotating angle. This procedure was repeated for all points in the articular surface model of the donor patella. Step-off was then calculated as the least mean square difference between the defect and graft along the periphery. Stepwise linear regression was used for each defect location to analyze which variables predict degree of mismatch in millimeters. Results: A total of 16 patella were utilized in analysis. Comparison of cartilage least mean square distances between locations demonstrated that the lateral location had significantly less surface incongruity compared to the other two locations (vs medial: p = .0038, vs central: p = .0046). In addition, significant differences in subchondral bone distances were observed between the locations (lateral vs medial: p = .0007, lateral vs central: p < .0001, medial vs central: p < .0001) (Table 1). The associations of six anatomic and morphologic variables with cartilage mismatch, bone mismatch, and step-off for 18 mm and 22.5 mm defects are presented in Tables 2 and Table 3. All variables were analyzed as the difference in value between the recipient and donor. For both lesion sizes, cartilage step-off was the most susceptible to variable differences. Compared to the 18 mm defect group, the 22.5 mm defects were more affected (higher coefficients) by the same differences in variables. Differences in tibial width were associated mismatch for central lesions (eg. 22.5mm defect coefficient: -0.026, p < .001), while cartilage width was associated with mismatch for lateral lesions. (eg. 22.5 mm defect coefficient: -0.034, p < .023). Conclusions: Multiple clinically relevant factors were found to affect graft and defect chondral mismatch and to a lesser extent osseous mismatch. For all three locations at both defect sizes, step-off was the most susceptible to differences in patellar morphology between the donor and recipient. In addition, differences in tibial width, a commonly used metric for patellar graft matching, did not significantly predict chondral mismatch for lateral and medial sized lesions. These findings should be considered when selecting and preparing the graft in a patella osteochondral allograft procedure.

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