The split-line pattern of the distal femur

Below, Steven; Arnoczky, Steven P.; Dodds, Julie; Kooima, Cynthia; Walter, Norman

doi:10.1053/jars.2002.29877

Cited by 91 publications

(23 citation statements)

References 19 publications

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“…In a vertical plane, fluid pressure was essentially ). Four different fiber orientations were considered as shown with A, B, C and D zones (adapted from the split-lines in [7]). The size of the tissue considered is 14 9 10 9 2 mm with 2 mm in the depth or z direction.…”

Section: Resultsmentioning

confidence: 99%

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Three-dimensional fibril-reinforced finite element model of articular cartilage

Cheung

2009

Med Biol Eng Comput

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Collagen fiber orientations in articular cartilage are tissue depth-dependent and joint site-specific. A realistic three-dimensional (3D) fiber orientation has not been implemented in modeling fluid flow-dependent response of articular cartilage; thus the detailed mechanical role of the collagen network may have not been fully understood. In the present study, a previously developed fibril-reinforced model of articular cartilage was extended to account for the 3D fiber orientation. A numerical procedure for the material model was incorporated into the finite element code ABAQUS using the "user material" option. Unconfined compression and indentation testing was evaluated. For indentation testing, we considered a mechanical contact between a solid indenter and a medial femoral condyle, assuming fiber orientations in the surface layer to follow the split-line pattern. The numerical results from the 3D modeling for unconfined compression seemed reasonably to deviate from that of axisymmetric modeling. Significant fiber orientation dependence was observed in the displacement, fluid pressure and velocity for the cases of moderate strain-rates, or during early relaxation. The influence of fiber orientation diminished at static and instantaneous compressions.

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Section: Resultsmentioning

confidence: 99%

“…1). The split-line pattern [7] was used to determine the primary fiber orientations. Cartilage thickness was taken to be 2 mm, in agreement with published values [1,40].…”

Section: Methodsmentioning

confidence: 99%

Three-dimensional fibril-reinforced finite element model of articular cartilage

Cheung

2009

Med Biol Eng Comput

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“…Local split-line direction was visualized by inserting a surgical needle dipped in India ink (Below et al, 2002) into the cartilage surface immediately adjacent to each 6 mm diameter explant (Figure 1A). Each explant was cut in half either parallel to or perpendicular to the local split-line direction, removed from the condyle, and wrapped in gauze soaked in phosphate buffered saline (PBS) for intermediate storage at −20°C.…”

Section: Methodsmentioning

confidence: 99%

“…Based on distance from the articular surface, the ECM is divided into three zones (superficial, middle, and deep) that vary in molecular composition (Muir et al, 1970; Venn and Maroudas, 1977) and matrix architecture (Hwang et al, 1992; Jeffery et al, 1991; Vanden Berg-Foels et al, 2012; Yin et al, 2011). Split-lines are indicative of the preferred collagen fiber orientation parallel to the articular surface (Below et al, 2002; Meachim et al, 1974) and provide an additional component of structural anisotropy. Variations in composition and ultrastructure contribute to the depth- (Chen et al, 2001; Jurvelin et al, 1997; Kempson et al, 1973; Schinagl et al, 1997; Wang et al, 2002a; Wang et al, 2002b; Wu and Herzog, 2002) and directional-dependent (Chahine et al, 2004; Huang et al, 2005; Jurvelin et al, 2003; Mizrahi et al, 1986; Wang et al, 2003) macroscale mechanical properties of the cartilage ECM.…”

Section: Introductionmentioning

confidence: 99%

Depth-dependent anisotropy of the micromechanical properties of the extracellular and pericellular matrices of articular cartilage evaluated via atomic force microscopy

McLeod

Wilusz

Guilak

2013

Journal of Biomechanics

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The extracellular matrix (ECM) of articular cartilage is structurally and mechanically inhomogeneous and anisotropic, exhibiting variations in composition, collagen fiber architecture, and pericellular matrix (PCM) morphology among the different zones (superficial, middle, and deep). Joint loading exposes chondrocytes to a complex biomechanical environment, as the microscale mechanical environment of the chondrocyte depends on the relative properties of its PCM and local ECM. ECM anisotropy and chondrocyte deformation are influenced by the split-line direction, the preferred collagen fiber orientation parallel to the articular surface. While previous studies have demonstrated that cartilage macroscale properties vary with depth and the direction of loading relative to the split-line direction, the potential anisotropic behavior of the ECM and PCM at the microscale has yet to be examined. The goal of this study was to characterize the depth and directional dependence of the microscale biomechanical properties of porcine cartilage ECM and PCM in situ. Cartilage was cryosectioned to generate samples oriented parallel and perpendicular to the split-line direction and normal to the articular surface. Atomic force microscopy (AFM)-based stiffness mapping was utilized to measure ECM and PCM microscale elastic properties in all three directions within each zone. Distinct anisotropy in ECM elastic moduli was observed in the superficial and deep zones, while the middle zone exhibited subtle anisotropy. PCM elastic moduli exhibited zonal uniformity with depth and directional dependence when pooled across the zones. These findings provide new evidence for mechanical inhomogeneity and anisotropy at the microscale in articular cartilage.

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“…In the superficial zone, the fibers were oriented according to the split lines recorded from the surface ([32]; adopted from Figure 2 in [30]). In the middle zone, the fibers did not have any specific orientation.…”

Section: Methodsmentioning

confidence: 99%

Altered Knee Joint Mechanics in Simple Compression Associated with Early Cartilage Degeneration

Dabiri

2013

Computational and Mathematical Methods in Medicine

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The progression of osteoarthritis can be accompanied by depth-dependent changes in the properties of articular cartilage. The objective of the present study was to determine the subsequent alteration in the fluid pressurization in the human knee using a three-dimensional computer model. Only a small compression in the femur-tibia direction was applied to avoid numerical difficulties. The material model for articular cartilages and menisci included fluid, fibrillar and nonfibrillar matrices as distinct constituents. The knee model consisted of distal femur, femoral cartilage, menisci, tibial cartilage, and proximal tibia. Cartilage degeneration was modeled in the high load-bearing region of the medial condyle of the femur with reduced fibrillar and nonfibrillar elastic properties and increased hydraulic permeability. Three case studies were implemented to simulate (1) the onset of cartilage degeneration from the superficial zone, (2) the progression of cartilage degeneration to the middle zone, and (3) the progression of cartilage degeneration to the deep zone. As compared with a normal knee of the same compression, reduced fluid pressurization was observed in the degenerated knee. Furthermore, faster reduction in fluid pressure was observed with the onset of cartilage degeneration in the superficial zone and progression to the middle zone, as compared to progression to the deep zone. On the other hand, cartilage degeneration in any zone would reduce the fluid pressure in all three zones. The shear strains at the cartilage-bone interface were increased when cartilage degeneration was eventually advanced to the deep zone. The present study revealed, at the joint level, altered fluid pressurization and strains with the depth-wise cartilage degeneration. The results also indicated redistribution of stresses within the tissue and relocation of the loading between the tissue matrix and fluid pressure. These results may only be qualitatively interesting due to the small compression considered.

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The split-line pattern of the distal femur

Cited by 91 publications

References 19 publications

Three-dimensional fibril-reinforced finite element model of articular cartilage

Three-dimensional fibril-reinforced finite element model of articular cartilage

Depth-dependent anisotropy of the micromechanical properties of the extracellular and pericellular matrices of articular cartilage evaluated via atomic force microscopy

Altered Knee Joint Mechanics in Simple Compression Associated with Early Cartilage Degeneration

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