1
|
Sabouri P, Hashemi A. Effect of loading direction and anatomical location on the ultimate tensile stress, fracture toughness, and failure patterns of knee meniscus. Knee 2024; 48:120-127. [PMID: 38579436 DOI: 10.1016/j.knee.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 01/05/2024] [Accepted: 03/18/2024] [Indexed: 04/07/2024]
Abstract
BACKGROUND Rupture of the knee menisci is a common injury that can have implications for other conditions, such as osteoarthritis. The fracture toughness of soft tissue (Jc) is a mechanical property that characterizes its resistance to tear extension. To date, Jc of the meniscus has not been quantified. METHODS Cyclic tensile tests were conducted on meniscus samples to determine Jc and explore its characteristics. Initially, the study investigated the impact of an initial notch on the ultimate tensile stress. This allowed for an understanding of how the presence of a notch affects its structural integrity. Subsequently, Jc was measured in both the radial and circumferential directions to assess its loading direction dependency. Furthermore, the study assessed the effect of anatomical location by comparing samples collected from the femoral and tibial layers. RESULTS Defect tolerance of the meniscus is influenced by the loading direction. In the circumferential direction, the presence of an initial notch did not affect the ultimate stress, and no crack expansion was observed. In radial samples with a notch length of 40% or more of the total width, crack propagation occurred, leading to a decrease in the ultimate stress (p< 0.01). Additionally, Jc was found to be higher in the femoral layer compared to the tibial layer (p= 0.017). CONCLUSION The study also examined the failure patterns of the meniscus to enhance our understanding of its pathology. These insights contribute to a better comprehension of meniscus injuries and can aid in the development of more effective treatment strategies.
Collapse
Affiliation(s)
- Pouya Sabouri
- Biomechanical Engineering Group, Biomedical Engineering Department, Amirkabir University of Technology (Tehran Polytechnic), Tehran 15875-4413, Iran
| | - Ata Hashemi
- Biomechanical Engineering Group, Biomedical Engineering Department, Amirkabir University of Technology (Tehran Polytechnic), Tehran 15875-4413, Iran.
| |
Collapse
|
2
|
Waghorne J, Bonomo FP, Rabbani A, Bell D, Barrera O. On the characteristics of natural hydraulic dampers: An image-based approach to study the fluid flow behaviour inside the human meniscal tissue. Acta Biomater 2024; 175:157-169. [PMID: 38159896 DOI: 10.1016/j.actbio.2023.12.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 12/18/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
The meniscal tissue is a layered material with varying properties influenced by collagen content and arrangement. Understanding the relationship between structure and properties is crucial for disease management, treatment development, and biomaterial design. The internal layer of the meniscus is softer and more deformable than the outer layers, thanks to interconnected collagen channels that guide fluid flow. To investigate these relationships, we propose an integrated approach that combines Computational Fluid Dynamics (CFD) with Image Analysis (CFD-IA). We analyze fluid flow in the internal architecture of the human meniscus across a range of inlet velocities (0.1 mm/s to 1.6 m/s) using high-resolution 3D micro-computed tomography scans. Statistical correlations are observed between architectural parameters (tortuosity, connectivity, porosity, pore size) and fluid flow parameters (Re number distribution, permeability). Some channels exhibit Re values of 1400 at an inlet velocity of 1.6 m/s, and a transition from Darcy's regime to a non-Darcian regime occurs around an inlet velocity of 0.02 m/s. Location-dependent permeability ranges from 20-32 Darcy. Regression modelling reveals a strong correlation between fluid velocity and tortuosity at high inlet velocities, as well as with channel diameter at low inlet velocities. At higher inlet velocities, flow paths deviate more from the preferential direction, resulting in a decrease in the concentration parameter by an average of 0.4. This research provides valuable insights into the fluid flow behaviour within the meniscus and its structural influences. 3D models and image stack are available to download at https://doi.org/10.5281/zenodo.10401592. STATEMENT OF SIGNIFICANCE: The meniscus is a highly porous soft tissue with remarkable properties of load transfer and energy absorption. We give insight on the mechanism of energy absorption from high resolution uCT scans, never presented before, and a new method which combine CFD and image. The structure is similar to a sandwich structure with a stiff outside layer and a soft internal layer made of collagen channels oriented in a preferential direction guiding the fluid flow, enabling it to accommodate deformation and dissipate energy, making it a potentially optimized damping system. We investigate architectural/ fluid flow parameters- fluid regimes relationship, which is of interest of the readers working on designing suitable biomimetic systems that can be adopted for replacement.
Collapse
Affiliation(s)
- Jack Waghorne
- School of Engineering, Computing and Mathematics, Oxford Brookes University, Oxford, United Kingdom
| | - Francesco Paolo Bonomo
- Advanced Technology Network Center (ATeN Center), Universitá degli Studi di Palermo, Palermo 90128, Italy
| | | | - Daniel Bell
- School of Engineering, Computing and Mathematics, Oxford Brookes University, Oxford, United Kingdom
| | - Olga Barrera
- School of Engineering, Computing and Mathematics, Oxford Brookes University, Oxford, United Kingdom; Department of Engineering Science, University of Oxford, United Kingdom.
| |
Collapse
|
3
|
Morejon A, Schwartz G, Best TM, Travascio F, Jackson AR. Effect of molecular weight and tissue layer on solute partitioning in the knee meniscus. OSTEOARTHRITIS AND CARTILAGE OPEN 2023; 5:100360. [PMID: 37122844 PMCID: PMC10133802 DOI: 10.1016/j.ocarto.2023.100360] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 04/04/2023] [Indexed: 05/02/2023] Open
Abstract
Objective Knee meniscus tissue is partly vascularized, meaning that nutrients must be transported through the extracellular matrix of the avascular portion to reach resident cells. Similarly, drugs used as therapeutic agents to treat meniscal pathologies rely on transport through the tissue. The driving force of diffusive transport is the gradient of concentration, which depends on molecular solubility. The meniscus is organized into a core region sandwiched between the tibial and femoral superficial layers. Structural differences exist across meniscal regions; therefore, regional differences in solubility are also hypothesized. Methods Samples from the core, tibial and femoral layers were obtained from 5 medial and 5 lateral porcine menisci. The partition coefficient (K) of fluorescein, 3 kDa and 40 kDa dextrans in the layers of the meniscus was measured using an equilibration experiment. The effect of meniscal compartment, layer, and solute molecular weight on K was analyzed using a three-way ANOVA. Results K ranged from a high of ∼2.9 in fluorescein to a low of ∼0.1 in 40 kDa dextran and was inversely related to the solute molecular weight across all tissue regions. Tissue layer only had a significant effect on partitioning of 40k Dex solute, which was lower in the tibial surface layer relative to the core (p = 0.032). Conclusion This study provides insight into depth-dependent partitioning in the meniscus, indicating the limiting effect of the meniscus superficial layer on solubility increases with solute molecular size. This illustrates how the surface layers could potentially reduce the effectiveness of drug delivery therapies incorporating large molecules (>40 kDa).
Collapse
Affiliation(s)
- Andy Morejon
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL, USA
| | - Gabi Schwartz
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Thomas M. Best
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
- Department of Orthopedic Surgery, University of Miami, Coral Gables, FL, USA
- UHealth Sports Medicine Institute, Coral Gables, FL, USA
| | - Francesco Travascio
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL, USA
- Department of Orthopedic Surgery, University of Miami, Coral Gables, FL, USA
- Max Biedermann Institute for Biomechanics at Mount Sinai Medical Center, Miami Beach, FL, USA
- Corresponding author. College of Engineering, University of Miami, 1251 Memorial Drive, MEB 276, Coral Gables, FL 33146, USA.
| | - Alicia R. Jackson
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
- Corresponding author. College of Engineering, University of Miami, 1251 Memorial Drive, MEA 219, Coral Gables, FL 33146 USA.
| |
Collapse
|
4
|
Morejon A, Dalbo PL, Best TM, Jackson AR, Travascio F. Tensile energy dissipation and mechanical properties of the knee meniscus: relationship with fiber orientation, tissue layer, and water content. Front Bioeng Biotechnol 2023; 11:1205512. [PMID: 37324417 PMCID: PMC10264653 DOI: 10.3389/fbioe.2023.1205512] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Introduction: The knee meniscus distributes and dampens mechanical loads. It is composed of water (∼70%) and a porous fibrous matrix (∼30%) with a central core that is reinforced by circumferential collagen fibers enclosed by mesh-like superficial tibial and femoral layers. Daily loading activities produce mechanical tensile loads which are transferred through and dissipated by the meniscus. Therefore, the objective of this study was to measure how tensile mechanical properties and extent of energy dissipation vary by tension direction, meniscal layer, and water content. Methods: The central regions of porcine meniscal pairs (n = 8) were cut into tensile samples (4.7 mm length, 2.1 mm width, and 0.356 mm thickness) from core, femoral and tibial components. Core samples were prepared parallel (circumferential) and perpendicular (radial) to the fibers. Tensile testing consisted of frequency sweeps (0.01-1Hz) followed by quasi-static loading to failure. Dynamic testing yielded energy dissipation (ED), complex modulus (E*), and phase shift (δ) while quasi-static tests yielded Young's Modulus (E), ultimate tensile strength (UTS), and strain at UTS (εUTS). To investigate how ED is influenced by the specific mechanical parameters, linear regressions were performed. Correlations between sample water content (φw) and mechanical properties were investigated. A total of 64 samples were evaluated. Results: Dynamic tests showed that increasing loading frequency significantly reduced ED (p < 0.05). Circumferential samples had higher ED, E*, E, and UTS than radial ones (p < 0.001). Stiffness was highly correlated with ED (R2 > 0.75, p < 0.01). No differences were found between superficial and circumferential core layers. ED, E*, E, and UTS trended negatively with φw (p < 0.05). Discussion: Energy dissipation, stiffness, and strength are highly dependent on loading direction. A significant amount of energy dissipation may be associated with time-dependent reorganization of matrix fibers. This is the first study to analyze the tensile dynamic properties and energy dissipation of the meniscus surface layers. Results provide new insights on the mechanics and function of meniscal tissue.
Collapse
Affiliation(s)
- Andy Morejon
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL, United States
| | - Pedro L. Dalbo
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Thomas M. Best
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
- Department of Orthopedic Surgery, University of Miami, Coral Gables, FL, United States
- UHealth Sports Medicine Institute, Coral Gables, FL, United States
| | - Alicia R. Jackson
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Francesco Travascio
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL, United States
- Department of Orthopedic Surgery, University of Miami, Coral Gables, FL, United States
- Max Biedermann Institute for Biomechanics at Mount Sinai Medical Center, Miami Beach, FL, United States
| |
Collapse
|