The lubricating ability of biomembrane models with dipalmitoyl phosphatidylcholine and γ-globulin

1998 ◽  
Vol 212 (5) ◽  
pp. 337-346 ◽  
Author(s):  
H Higaki ◽  
T Murakami ◽  
Y Nakanishi ◽  
H Miura ◽  
T Mawatari ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Synovial Fluid ◽  
Articular Surface ◽  
Glass Plate ◽  
Sodium Hyaluronate ◽  
Load Condition ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Adsorbed Films ◽  
Articular Surfaces ◽  
Frictional Behaviour

Two kinds of friction tests were conducted to investigate the lubricating effect of the injection of amphiphilies on the osteoarthritic joint. The effects of the addition of Lα-dipalmitoyl phosphatidylcholine (Lα-DPPC) riposomes and γ-globulin in a saline solution of sodium hyaluronate (HA) were evaluated through pendulum friction tests. The frictional characteristics of pig shoulder joints were confirmed to depend on the viscosity of the lubricants only in the physiologically low load condition and in the condition immediately after loading. Detergent (polyoxyethylene p-t-octylphenyl ether) was successfully used to remove adsorbed films from the articular surfaces. The friction coefficient of natural synovial joints was significantly increased in a mode of mixed lubrication with the HA solution of 0.2 g/dl by the treatment of the surface with the detergent. The addition of Lα-DPPC riposomes or y-globulin significantly improved the boundary lubricating ability of the articular surfaces treated with the detergent, depending on the quantity of those additives. It appears that the Lα-DPPC riposomes and γ-globulin can form protective films on the articular surfaces like a biomembrane. Moreover, the reciprocating frictional behaviour in sliding pairs of pig articular cartilages and glass plates was studied in order to elucidate the tribological role of those constituents in the boundary lubricating film on the articular surface. Pig synovial fluid and water solutions of HA were used as lubricants. The synovial fluid had superior lubricating ability compared to the HA solution of equivalent viscosity under a physiologically high load condition. This fact seems to be responsible for the boundary lubricating ability of constituents other than hyaluronic acid. Langmuir-Blodgett (LB) films of Lα-DPPC on the glass plate were kept at a low and stable friction coefficient, depending on the number of film layers. In conditions of mixed films with Lα-DPPC and γ-globulin, the frictional behaviour was improved by increasing the quantity of γ-globulin. A model is proposed in which the effective adsorbed films are composed of proteins, phospholipids and other conjugated constituents on the articular surfaces to be accurate in describing the boundary lubricating mechanism. The mechanism is controlled by hydrophobic groups in those amphiphilies.

scholarly journals The Effect of Synovial Fluid Composition, Speed and Load on Frictional Behaviour of Articular Cartilage

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1334 ◽  
Author(s):  
Denis Furmann ◽  
David Nečas ◽  
David Rebenda ◽  
Pavel Čípek ◽  
Martin Vrbka ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Friction Coefficient ◽  
Synovial Fluid ◽  
Glass Plate ◽  
Fluid Composition ◽  
Tribological Behaviour ◽  
Number Of Patients ◽  
Model Fluids ◽  
Frictional Behaviour

Articular cartilage ensures smooth motion of natural synovial joints operating at very low friction. However, the number of patients suffering from joint diseases, usually associated with cartilage degradation, continuously increases. Therefore, an understanding of cartilage tribological behaviour is of great interest in order to minimize its degradation, preserving the reliable function of the joints. The aim of the present study is to provide a comprehensive comparison of frictional behaviour of articular cartilage, focusing on the effect of synovial fluid composition (i), speed (ii), and load (iii). The experiments were realized using a pin-on-plate tribometer with reciprocating motion. The articular cartilage pin was loaded against smooth glass plate while the tests consisted of loading and unloading phases in order to enable cartilage rehydration. Various model fluids containing albumin, γ-globulin, hyaluronic acid, and phospholipids were prepared in two different concentrations simulating physiologic and osteoarthritic synovial fluid. Two different speeds, 5 mm/s and 10 mm/s were applied, and the tests were carried out under 5 N and 10 N. It was found that protein-based solutions exhibit almost no difference in friction coefficient, independently of the concentration of the constituents. However, the behaviour is considerably changed when adding hyaluronic acid and phospholipids. Especially when interacting with γ-globulin, friction coefficient decreased substantially. In general, an important role of the interaction of fluid constituents was observed. On the other hand, a limited effect of speed was detected for most of the model fluids. Finally, it was shown that elevated load leads to lower friction, which corresponds well with previous observations. Further study should concentrate on specific explored phenomena focusing on the detailed statistical evaluation.

A Mechanism to Explain Physiological Lubrication

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
David F. James ◽  
Garret M. Fick ◽  
W. Douglas Baines
Keyword(s):  
Hyaluronic Acid ◽  
Synovial Fluid ◽  
Articular Surface ◽  
Constant Load ◽  
Squeeze Film ◽  
Hydrodynamic Resistance ◽  
Low Viscosity ◽  
Electrostatic Charges ◽  
Articular Surfaces

A new mechanism of physiological lubrication is proposed to explain how low-viscosity synovial fluid prevents articular surfaces from contacting and wearing. The new mechanism is based on the hypothesis that the hyaluronic acid chains in synovial fluid bind to the cartilage surfaces through electrostatic charges, with the phospholipid layer on an articular surface supplying the necessary attractive charges. The stationary hyaluronic acid network causes a large hydrodynamic resistance to outward flow from the gap. To determine the effectiveness of the network in preventing contact, squeeze-film flow between two incompressible, permeable disks is analyzed when a constant load is suddenly applied, and the solvent—synovial fluid minus the hyaluronic acid—escapes through the network and through the permeable disks. The analysis yields the approximate time for the gap distance to decrease to asperity size. For realistic physiological parameters, the time for the surfaces to contact is a minimum of several minutes and likely much longer. The role of albumin in the synovial fluid is included because the large protein molecules are trapped by the small openings in the hyaluronic acid network, which increases the flow resistance of the network and thereby delays contact of the surfaces.

IDENTIFICATION OF FRICTION CONDITIONS IN HUMAN JOINTS

Tribologia ◽  
2017 ◽  
Vol 273 (3) ◽  
pp. 127-136
Author(s):  
Andrzej RYNIEWICZ ◽  
Anna RYNIEWICZ
Keyword(s):  
Image Analysis ◽  
Synovial Fluid ◽  
Diagnostic Imaging ◽  
Layer Structure ◽  
Articular Surface ◽  
Fem Simulation ◽  
Lubrication Mechanism ◽  
Articular Surfaces ◽  
Ankle Joints ◽  
Human Joints

The purpose of the paper is to explain the friction conditions and the lubrication mechanism in healthy joints, based on rheological tests of synovial fluid and the identification of structures and the shape of articular surfaces. The tests were performed on cadaver preparations of large lower limp joints: hip, knee, and ankle joints. The analysis included combined experimental activities with the use of modern research and test techniques in the area of viscosity and microscopy as well as diagnostic imaging, image analysis, modelling, and FEM simulation. The tests performed allowed for the analysis of lubrication process which can be described as bioelastohydrodynamic lubrication (BEHL). The most important are viscoelasticity properties of the synovial fluid and the process whereby the external load is taken over by the pressure generated by a set of oil wedges of synovial fluid formed by naturally wavy articular surface. The multi-layer structure of the joints is characterised by variable wavy shape of cartilaginous surfaces and of bone tissue and by the variable wavy thickness of the cartilage.

scholarly journals Morphometric evaluation of features of remodeling of chondrocites of joint surfaces of temporomandibular joint of experimental animals in hyperglycemia

2021 ◽  
Vol 11 (6) ◽  
pp. 137-142
Author(s):  
Mykhailo Hnatiuk ◽  
Lesia Rubas
Keyword(s):  
Temporomandibular Joint ◽  
Structural Changes ◽  
Articular Surface ◽  
White Male ◽  
Relative Volume ◽  
Male Rats ◽  
Intercellular Substance ◽  
Temporal Fossa ◽  
Articular Surfaces ◽  
Joint Surfaces

Aim: to study morphometrically the peculiarities of remodeling of chondrocytes of the articular surfaces of the temporomandibular joint in hyperglycemia.Materials and methods: Quantitative morphological methods were used to study diameters of chondrocytes and their nuclei, nuclear-cytoplasmic relationship in these cells, relative volume of damaged chondrocytes, intercellular-chondrocytic relationship in mature chondrocytes of the articular surfaces of the temporomandibular joint of 45 laboratory mature white male rats with simulated diabetes.Results: A comprehensive analysis of the morphometric parameters presented in the article showed that they did not differ in the articular surfaces of the temporal fossa and mandibular head of the intact temporomandibular joint. The expressed structural changes of chondrocytes were revealed at a monthly and a two-month diabetic arthropathy of this joint.Conclusions: Proceeded studies and obtained results suggest that prolonged hyperglycemia leads to diabetic arthropathy of the TMJ, which is characterized by atrophy of chondrocytes, violation of nuclear-cytoplasmic relationships, an increase in the relative volume of damaged chondrocytes and volume of intercellular substance. The detected changes in quantitative morphological parameters depended on the duration of hyperglycemia and dominated in the cartilaginous tissue of the articular surface of the mandibular head.

The temporomandibular joints, muscles of mastication, and the infratemporal and pterygopalatine fossae

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Temporal Bone ◽  
Articular Surface ◽  
Mandibular Condyle ◽  
Jaw Movements ◽  
Synovial Joints ◽  
Articular Surfaces ◽  
Temporomandibular Joints ◽  
Mandibular Fossa ◽  
Muscle Groups ◽  
Muscles Of Mastication

It is essential that dental students and practitioners understand the structure and function of the temporomandibular joints and the muscles of mastication and other muscle groups that move them. The infratemporal fossa and pterygopalatine fossa are deep to the mandible and its related muscles; many of the nerves and blood vessels supplying the structures of the mouth run through or close to these areas, therefore, knowledge of the anatomy of these regions and their contents is essential for understanding the dental region. The temporomandibular joints (TMJ) are the only freely movable articulations in the skull together with the joints between the ossicles of the middle ear; they are all synovial joints. The muscles of mastication move the TMJ and the suprahyoid and infrahyoid muscles also play a significant role in jaw movements. The articular surfaces of the squamous temporal bone and of the condylar head (condyle) of the mandible form each temporomandibular joint. These surfaces have been briefly described in Chapter 22 on the skull and Figure 24.1A indicates their shape. The concave mandibular fossa is the posterior articulating surface of each squamous temporal bone and houses the mandibular condyle at rest. The condyle is translated forwards on to the convex articular eminence anterior to the mandibular fossa during jaw movements. The articular surfaces of temporomandibular joints are atypical; they covered by fibrocartilage (mostly collagen with some chondrocytes) instead of hyaline cartilage found in most other synovial joints. Figures 24.1B and 24.1C show the capsule and ligaments associated with the TMJ. The tough, fibrous capsule is attached above to the anterior lip of the squamotympanic fissure and to the squamous bone around the margin of the upper articular surface and below to the neck of the mandible a short distance below the limit of the lower articular surface. The capsule is slack between the articular disc and the squamous bone, but much tighter between the disc and the neck of the mandible. Part of the lateral pterygoid muscle is inserted into the anterior surface of the capsule. As in other synovial joints, the non-load-bearing internal surfaces of the joint are covered with synovial membrane.

scholarly journals Stress Distribution Patterns Across the Shoulder Joint in Gymnasts: A Computed Tomography Osteoabsorptiometry Study

2020 ◽  
Vol 8 (11) ◽  
pp. 232596712096210
Author(s):  
Daisuke Momma ◽  
Wataru Iwamoto ◽  
Kaori Endo ◽  
Kazuki Sato ◽  
Norimasa Iwasaki
Keyword(s):  
Bone Density ◽  
Stress Distribution ◽  
Distribution Pattern ◽  
Subchondral Bone ◽  
Shoulder Joint ◽  
Glenohumeral Joint ◽  
Articular Surface ◽  
Articular Surfaces ◽  
Subchondral Bone Density ◽  
Collegiate Gymnasts

Background: The distribution pattern of subchondral bone density is an indicator of stress distribution over a joint surface under long-term physiologic loading. The biomechanical characteristics of the articular surfaces of the shoulder joint in gymnasts can be determined by measuring this distribution pattern. Purpose: To evaluate the distribution of subchondral bone density across the shoulder joint in male collegiate gymnasts and to determine the effects of gymnastic activities on its articular surfaces under long-term loading conditions using computed tomography osteoabsorptiometry (CTOAM). Study Design: Descriptive laboratory study. Methods: CT image data were obtained from both shoulders of 12 asymptomatic male collegiate gymnasts (gymnast group; mean age, 19.4 years; range, 18-22 years) and 10 male collegiate volunteers (control group; mean age, 20.2 years; range, 18-22 years). The distribution pattern of subchondral bone density across the articular surfaces of each shoulder joint was assessed by CTOAM. Quantitative analysis was performed of the locations and percentages of high-density areas on the articular surface. Results: Stress distribution patterns over the articular surfaces differed between the gymnasts and the controls. In the gymnasts, high-density areas were detected on the posterosuperior articular surface of the humeral head and the anterosuperior and/or posterosuperior articular surface of the glenoid. Mean bone density was greater in the gymnasts than in the controls ( P < .0001). Conclusion: Stress distribution over the articular surfaces of the shoulder joint was affected by gymnastic activities. Stress was concentrated over the superior part of the glenohumeral joint in male collegiate gymnasts. Clinical Relevance: The present findings suggest that gymnastic activities increase stress to the articular surfaces of the superior glenohumeral joint. This supports the notion that mechanical conditions play a crucial role in the origin of disorders particular to gymnastic activities.

scholarly journals Two-millimetre diameter operative arthroscopy of the ankle is safe and effective

2020 ◽  
Vol 28 (10) ◽  
pp. 3080-3086 ◽  
Author(s):  
Tobias Stornebrink ◽  
J. Nienke Altink ◽  
Daniel Appelt ◽  
Coen A. Wijdicks ◽  
Sjoerd A. S. Stufkens ◽  
...  
Keyword(s):  
Articular Surface ◽  
Anteromedial Portal ◽  
Human Donor ◽  
Articular Surfaces ◽  
Iatrogenic Damage ◽  
Anterolateral Portal ◽  
Fresh Frozen ◽  
Effective Visualization ◽  
Neurovascular Structures ◽  
Portal Tracts

Abstract Purpose Technical innovation now offers the possibility of 2-mm diameter operative arthroscopy: an alternative to conventional arthroscopy that no longer uses inner rod-lenses. The purpose of this study was to assess whether all significant structures in the ankle could be visualized and surgically reached during 2-mm diameter operative arthroscopy, without inflicting iatrogenic damage. Methods A novel, 2-mm diameter arthroscopic system was used to perform a protocolled arthroscopic procedure in 10 fresh-frozen, human donor ankles. Standard anteromedial and anterolateral portals were utilized. Visualization and reach with tailored arthroscopic instruments of a protocolled list of articular structures were recorded and documented. A line was etched on the most posterior border of the talar and tibial cartilage that was safely reachable. The specimens were dissected and distances between portal tracts and neurovascular structures were measured. The articular surfaces of talus and tibia were photographed and inspected for iatrogenic damage. The reachable area on the articular surface was calculated and analysed. Results All significant structures were successfully visualized and reached in all specimens. The anteromedial portal was not in contact with neurovascular structures in any specimen. The anterolateral portal collided with a branch of the superficial peroneal nerve in one case but did not cause macroscopically apparent harm. On average, 96% and 85% of the talar and tibial surfaces was reachable respectively, without causing iatrogenic damage. Conclusion 2-mm diameter operative arthroscopy provides safe and effective visualization and surgical reach of the anterior ankle joint. It may hold the potential to make ankle arthroscopy less invasive and more accessible.

scholarly journals Static Strength of Friction-Type High-Strength Bolted T-Stub Connections under Shear and Compression

2020 ◽  
Vol 10 (10) ◽  
pp. 3600 ◽  
Author(s):  
Gangnian Xu ◽  
Youzhi Wang ◽  
Yefeng Du ◽  
Wenshuai Zhao ◽  
Laiyong Wang
Keyword(s):  
Friction Coefficient ◽  
Ultimate Strength ◽  
Compression Ratio ◽  
Failure Modes ◽  
Load Condition ◽  
High Strength ◽  
Shear Capacity ◽  
Displacement Curve ◽  
Clamping Force ◽  
Bolt Diameter

The friction-type high-strength bolted (FHSB) T-stub connection has been widely used in steel structures, due to their good fatigue resistance and ease of installation. While the current studies on FHSB T-stub connections mainly focus on the structural behaviors under both shear and tensile force, no research has been reported on the mechanical responses of the connections under the combined effects of shear and compression. To make up for this gap, this paper presents a novel FHSB T-stub connection, which is simple in structure, definite in load condition, and easy to construct. Static load tests were carried out on 21 specimens under different shear–compression ratios, and the finite-element (FE) models were created for each specimen. The failure modes, initial friction loads and ultimate strengths of the specimens were compared in details. Then, 144 FE models were adopted to analyze the effects of the friction coefficient, shear–compression ratio, bolt diameter and clamping force on the initial friction load and ultimate strength. The results showed that the FHSB T-stub connection under shear and compression mainly suffers from bolt shearing failure. The load–displacement curve generally covers the elastic, yield, hardening and failure stage. If the shear–compression ratio is small and the friction coefficient is large, its curve only contains the elastic and failure stage. The friction coefficient and shear–compression ratio have great impacts on the initial friction load and ultimate strength. For every 1 mm increase in bolt diameter, the initial friction load increased by about 10%, while the ultimate strength increased by about 8.5%. For each 10% increase/decrease of the design clamping force, the initial friction load decreases/increases by 7.8%, while the ultimate load remains basically the same. The proposed formula of shear capacity and self-lock angles of FHSB T-stub connection can be applied to the design of CSS-enhanced prestressed concrete continuous box girder bridges (PSC-CBGBs) and diagonal bracing.

scholarly journals Ulnar articular surface 3-D landmarks and ecomorphology of small mammals: a case study of two early Miocene typotheres (Notoungulata) from Patagonia

2015 ◽  
Vol 106 (4) ◽  
pp. 315-323 ◽  
Author(s):  
Nahuel A. Muñoz ◽  
Guillermo H. Cassini ◽  
Adriana M. Candela ◽  
Sergio F. Vizcaíno
Keyword(s):  
Small Mammals ◽  
Articular Surface ◽  
Principal Component ◽  
Proximal Part ◽  
Early Miocene ◽  
Articular Surfaces ◽  
Functional Value ◽  
Forelimb Movements ◽  
Morphological Patterns

ABSTRACTArticular surfaces reflect the relative movements between adjacent bones, and the ones involved in the elbow joint provide information about forelimb movements and may be useful for making inferences about the substrate use. The proximal articular surface of the ulna was examined through 3-D geometric morphometrics, in order to assess its usefulness as a proxy for paleoecological interpretations; particularly for two small mammals from the early Miocene of Patagonia. The sample was composed of 22 extant small mammals (rodents, carnivorans and primates) and two extinct typotheres: Hegetotherium mirabile (Hegetotheriidae) and Interatherium robustum (Interatheriidae). Forty-five landmarks were taken and principal component analysis (PCA) was used to explore the morphospace structure. The results of PCA for the whole surface were inconclusive; therefore, successive analyses were made, subdividing the surface into sub-units. The PCA for the proximal part of the trochlear notch was the most informative, allowing the recognition of morphospaces with functional value: one for digging rodents and another for most climbers. Neither typothere would have had a specialisation for climbing or digging in the features analysed. This study allows morphological patterns on different parts of a joint to be detected; interpreted, at least partially, as differential responses to different kinds of mechanical stress.

Anatomical data on the craniocervical junction and their correlation with degenerative changes in 30 cadaveric specimens

2005 ◽  
Vol 3 (5) ◽  
pp. 379-385 ◽  
Author(s):  
Stefan A. König ◽  
Axel Goldammer ◽  
Hans-Ekkehart Vitzthum
Keyword(s):  
Articular Cartilage ◽  
Articular Surface ◽  
Craniocervical Junction ◽  
Degenerative Changes ◽  
Content Type ◽  
Articular Surfaces ◽  
Anatomical Data ◽  
Grade Ii ◽  
Grade Iii ◽  
Fine Print

>Object. The goal of this project was to measure vertebral dimensions at the craniocervical junction and to investigate degenerative changes in this region and their correlations with the anatomical data. These studies will assist in an understanding of biomechanical conditions in this region, which are clinically relevant in cases of cervicogenic headaches and vertigo. Methods. The authors examined 30 cadaveric specimens obtained from patients ranging in age from 24 to 88 years at death. Measurements of angles of the vertebrae were conducted using an imprint method. Microsections of osseous endplates and articular cartilage were graded according to their degrees of degeneration by using the Petersson classification (0, no sign of degeneration; I, superficial degeneration with several fragmentations; II, deeper degeneration with cartilaginous disintegration and penetrating ulceration; or III, complete cartilaginous degeneration with the appearance of subchondral bone in > 50% of the articular surface). The authors found Grade I changes in 100% of the occiput specimens. In the superior articular cartilage of C-1 no changes (Grade 0) were found in two specimens, whereas 6% of the specimens exhibited Grade II changes and 89% exhibited Grade I changes. In the inferior articular cartilage of C-1, 57% of the specimens displayed Grade I changes, 14% Grade II, and 20% Grade III changes. In the superior articular cartilage of C-2, 62.5% of the specimens displayed Grade I changes and 25% Grade II changes. At the occiput—C1 level the authors found a higher frequency of degeneration at the upper left articular surface of the atlas (Quadrants 1 and 3), and at the C1–2 level they found a higher frequency of degeneration at the upper left and upper right articular surfaces of the axis (Quadrants 2 and 3, respectively). Using the McNemar test, the authors investigated the frequency of affection of single quadrants in a left—right side comparison (lateral reversal). Significant differences were identified for Quadrant 2 of the upper left articular surface of C-2 and Quadrant 3 of the upper right articular surface of C-2. These results correlate with the analysis of single articular surfaces of the axis, but contradict the results for the atlas, in which no significant difference in the left—right side comparison was found. Conclusions. Severe degeneration in the atlantooccipital joints appears to be a rare condition, with no Grade II or III degeneration found in the occipital condyles and 6% Grade I, 89% Grade II, but no Grade III changes in the superior articular cartilage of the atlas. Degeneration of the inferior articular cartilage of C-1 and the superior articular cartilage of C-2 indicates that the atlantoaxial joint faces more intense mechanical exposure, which is increased at the upper joint surfaces.

Sign in / Sign up

Export Citation Format

Share Document