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Myelomeningocele (MMC) is a congenital defect of the spine characterised by meningeal and spinal cord protrusion through the open vertebral arches. This defect causes progressive prenatal damage of the spinal cord, leading to lifelong handicap. Although mid‐trimester surgical repair may reduce part of the handicap, an earlier and less invasive approach would further improve the prognosis, possibly minimising maternal and foetal risks. Several studies have proposed an alternative approach to surgical repair by covering the defect with a patch and protecting the exposed neural tissue. Our study aims to elaborate on a waterproof and biodegradable bioactive patch for MMC prenatal foetal repair. We developed a double‐layer patch that can provide a waterproof coverage for the spinal cord, with a bioactive side, conducive to cell proliferation, and an antiadhesive side to avoid its attachment to the medulla. [ABSTRACT FROM AUTHOR]

In this work an extension of the adaptive-elasticity theory is proposed in order to include the contribution of bone microdamage as a stimulus. Some aspects of damaged-bone tissue adaptation, brought about by a change of the daily loading history, are investigated. In particular, under the assumption of a small strain approximation and isothermal conditions, the solution of the remodeling rate equation for steady homogeneous stress is discussed and the damage effect upon the remodeling time constant is shown. The result is both theoretical and numerical, based on a recent theory of internal damaged-bone remodeling (Ramtani, S., and Zidi, M., 1999, 'Damaged-Bone Remodeling Theory: Thermodynamical Approach,' Mechanics Research Communications, Vol. 26, pp. 701-708. Ramtani, S., and Zidi, M., 2001, 'A Theoretical Model of the Effect of Continum Damage on a Bone Adaption Model, 'Journal of Biomechanics, Vol. 34, pp. 471-479) and motivated by the works of Cowin, S. C., and Hegedus, D. M., 1976, 'Bone Remodeling I: Theory and Adaptive Elasticity,' Journal of Elasticity, Vol. 6, pp. 471-479 and Hegedus, D. H., and Cowin, S. C., 1976, 'Bone Remodeling II: Small Strain Adaptive Elasticity,' Journal of Elasticity, Vol. 6, pp. 337-352. [DOI: 10.1115/1.1467918]

Bone remodeling is wifely viewed as a dynamic process--maintaining bone structure through a balance between the opposed activities of osteoblast and cells--in which the stability problem is often pointed out. By an analytical approach, we present a bone remodeling model applied to n unit-elements in order to analyze the stationary stares and the condition of their stability. In addition, this theory has been simulated in a computer model using the Finite Element Method (FEM) to show a relationship between the bone remodeling process and the stability analysis. [S0148-0731(00)01806-9]

For the aim of fixing and stabilizing the Total Knee Arthroplasty (TKA) tibial component, pull-out strength of the post is one of the most important factors to be considered. The material properties of bone, coupled with the principal dimensions of bone/post assembly such as diameter, interference fit and implantation length, may affect the pull-out strength of the post fixation. In this study, a cylindrical stainless steel post inserted in a pre-drilled High Density Polyethylene (HDPE) cylinder with an initial interference fit was taken as a model to assess the contribution of post fixation to the initial stability of TKA tibial component. Pull-out experiments were carried out for different initial interference fits and implantation lengths. Under pull-out loading, the micro-slip initiation and propagation at the post/cylinder interface was found to be progressive and was modeled using Coulomb friction at the interface. In order to examine the experimental ultimate pull-out force results, an analytical model was developed. The analytical model was fitted to the experimental results by adjusting the friction coefficient for the considered ranges of initial interference fit and implantation length. It was found that friction coefficient depends on initial interference fit (Δr) as well as on the initial contact pressure (σ0). For the considered interference fit values Δr = 0.1 mm, Δr = 0.2 mm and Δr = 0.3 mm (σ0 = 13.62 MPa, σ0 = 27.24 MPa and σ0 = 40.86 MPa), the values of adjusted friction coefficient are 0.091, 0.067 and 0.058, respectively. Finite Element simulation was also carried out for the pull-out test using the ABAQUS program. It was found that numerical, analytical and experimental results are all in good agreement. [ABSTRACT FROM AUTHOR]

Presents a study which investigated damage initiation due to the mode II elastic buckling of adaptive bone-plate. Role of trabecular bone in load transmission in major joints; Relative importance of bone density and architecture in etiology bone fractures; Effects of bone remodeling on the bone-plate buckling process.

Presents a study which focused on stress distribution analysis of a sheared and stretched fibrous-hyperelastic soft-layer. Cause of the typical anisotropic behavior and residual strain; Examples of biological composites; Examples of man-made composites.

Deals with a study which examined the bone remodelling process under microgravity using a finite element model. Materials and methods; Results; Discussion and conclusion.

In this paper, we explore the effects of biological (pathological) and mechanical damage on bone tissue within a benchmark model. Using the Finite Element Methodology, we analyze and numerically test the model's components, capabilities, and performance under physiologically and pathologically relevant conditions. Our findings demonstrate the model's effectiveness in simulating bone remodeling processes and self-repair mechanisms for micro-damage induced by biological internal conditions and mechanical external ones within bone tissue. This article is the second part of a series, where the first part presented the mathematical model and the biological and physical significance of the terms used in a simplified benchmark model. It explored the bone remodeling model's application, implementation, and results under physiological conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)