Related Experiment Video
Updated: Jun 16, 2026
07:57
An Experimental and Finite Element Protocol to Investigate the Transport of Neutral and Charged Solutes across Articular Cartilage
Published on: April 23, 2017
Anisotropic dynamic changes in the pore network structure, fluid diffusion and fluid flow in articular cartilage
George W Greene1, Bruno Zappone, Olle Söderman
1Materials Department, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
Biomaterials
|February 11, 2010
Summary
Dynamic compression of cartilage reveals that interstitial fluid pressure significantly impacts its microstructure and hydraulic properties. This dynamic response is crucial for joint lubrication and load support.
Area of Science:
- Biomedical Engineering
- Materials Science
- Biomechanics
Background:
- Cartilage deformation under load involves complex fluid flow and structural changes.
- Understanding the dynamic mechanical properties of cartilage is essential for joint health and function.
Purpose of the Study:
- To investigate the in situ mechanical strain response and interstitial fluid dynamics in cartilage during dynamic compression.
- To elucidate the relationship between hydrostatic pressure, pore structure, and fluid transport in deforming cartilage.
Main Methods:
- Utilized a custom-designed compression cell within an NMR spectrometer for in situ analysis.
- Investigated full-thickness cartilage samples under constant compressive load, distinguishing hydrostatic and pore pressures.
- Analyzed dynamic mechanical strain, structural changes, and interstitial water diffusion and flow.
Main Results:
- Hydrostatic pressure in interstitial fluid significantly influences cartilage microstructure, diffusion, and hydraulic conductivity, differing from static conditions.
- Cartilage exhibits a highly anisotropic pore structure and deformational dynamics, maintaining axial porosity even under large strains.
- Axial porosity insensitivity aids in directing pressurized fluid to the surface for load support and lubrication.
Conclusions:
- Dynamic interstitial fluid pressure is a key determinant of cartilage's mechanical and transport properties.
- The anisotropic structure of cartilage plays a vital role in its lubrication and load-bearing capabilities.
- Findings highlight the synergy between cartilage structure and hydrodynamic/boundary lubrication mechanisms for joint function.
Related Concept Videos
01:16Structural Joints: Synovial Joints
Synovial joints are the most common type of joint in the body. A key structural characteristic for a synovial joint is the presence of a joint cavity. This fluid-filled space is where the articulating surfaces of the bones contact each other. Also, unlike fibrous or cartilaginous joints, the articulating bone surfaces at a synovial joint are not directly connected to each other with fibrous connective tissue or cartilage. This gives the bones of a synovial joint the ability to move smoothly...
01:15Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
01:27Growth of Cartilage and Bone Tissue
Chondrocytes form a temporary cartilaginous model by dividing and secreting a thick gel-like extracellular matrix. Once the chondrocytes undergo programmed cell death, osteoblasts enter the site of the cartilaginous model. The process of replacing the temporary cartilaginous model with bone in an ordered manner is called endochondral ossification. In endochondral ossification, not all of the cartilage is replaced by bone tissue. Some cartilage that performs a protective and supportive function...
01:09Spongy Bone
All bones comprise an outer layer of compact bone, and an interior made up of spongy bone tissue, also called cancellous or trabecular bone. In long bones, spongy bone tissue is mainly found in the interior of the epiphyses (broad ends of the bone).
Spongy bone is more porous, and less dense compared to compact bone. It is composed of concentric lamellae that are arranged irregularly to form the trabecular network. In some bones, the spaces between trabeculae contain red marrow, where...
Spongy bone is more porous, and less dense compared to compact bone. It is composed of concentric lamellae that are arranged irregularly to form the trabecular network. In some bones, the spaces between trabeculae contain red marrow, where...
01:20Structural Classification of Joints
Joints, also known as articulations, are classified based on their structural characteristics, i.e., based on whether the articulating surfaces of the adjacent bones are directly connected by fibrous connective tissue or cartilage, or whether the articulating surfaces contact each other within a fluid-filled joint cavity. These differences serve to divide the joints of the body into three structural classifications.
A fibrous joint is where the adjacent bones are united by fibrous connective...
A fibrous joint is where the adjacent bones are united by fibrous connective...
01:11Pressure Variation in a Fluid at Rest
In a fluid at rest, the pressure at any point beneath the fluid surface depends solely on the depth, not on the container's shape or size. This principle, known as hydrostatic pressure, arises because, in stationary fluids, there is no acceleration, meaning the forces within the fluid balance out. Only vertical forces, caused by the weight of the fluid above, contribute to pressure changes with depth.
When measuring pressure at two different levels within the fluid, the difference in pressure...
When measuring pressure at two different levels within the fluid, the difference in pressure...