Water-content related alterations in macro and micro scale tendon biomechanics

Abstract

Though it is known that the water content of biological soft tissues alters mechanical properties, little attempt has been made to adjust the tissue water content prior to biomechanical testing as part of standardization procedures. The objective of this study was to examine the effects of altered water content on the macro and micro scale mechanical tissues properties. Human iliotibial band samples were obtained during autopsies to osmotically adapt their water content. Macro mechanical tensile testing of the samples was conducted with digital image correlation, and micro mechanical tests using atomic force microscopy. Analyses were conducted for elastic moduli, tensile strength, and strain at maximum force, and correlations for water content, anthropometric data, and post-mortem interval. Different mechanical properties exist at different water concentrations. Correlations to anthropometric data are more likely to be found at water concentrations close to the native state. These data underline the need for adapting the water content of soft tissues for macro and micro biomechanical experiments to optimize their validity. The osmotic stress protocol provides a feasible and reliable standardization approach to adjust for water content-related differences induced by age at death, post-mortem interval and tissue processing time with known impact on the stress-strain properties.

Phenoxyethanol‐Based Embalming for Anatomy Teaching: An 18 Years' Experience with Crosado Embalming at the University of Otago in New Zealand

“…The PE‐based fixation may be considered well suited for undergraduate teaching and partly suited for postgraduate education. The use of PE‐based tissues for biomechanical experiments should be limited to pilot trials on bones and ligaments, with unembalmed fresh tissues giving clearly superior results (Scholze et al, 2018; Lozano et al, 2019) as even small quantities of ethanol and formaldehyde are known to impact negatively on the load‐deformation behavior of bone (Hammer et al, 2014; Trowbridge et al, 2017; Becker et al, 2019) and soft tissue (Steinke et al, 2012; Hammer et al, 2016).…”

Biomechanical characterization of human temporal muscle fascia in uniaxial tensile tests for graft purposes in duraplasty

“…However, only four samples of one adult male embalmed human cadaver were tested in their study 14 . Their vastly limited sample size and the embalming chemicals will have likely dehydrated and denaturized the tissues, which results in higher elastic moduli 41 . The thicknesses of human TMF, dura mater and scalp samples were compared between Thiel-embalmed tissues and unembalmed tissues of the same origin before 23 .…”

What Is Considered a Variation of Biomechanical Parameters in Tensile Tests of Collagen-Rich Human Soft Tissues?—Critical Considerations Using the Human Cranial Dura Mater as a Representative Morpho-Mechanic Model

“…Beyond these measurement setup-related parameters, the biomechanical properties of soft tissues in tensile tests are influenced by the mechanical [ 5 , 11 , 12 ] and bio-physico-chemical [ 17 ] tissue composite of the samples. Recently, it was shown in human iliotibial tract samples that higher water contents were associated with both lower values for E mod and UTS [ 17 ]. However, the SF max remained largely uninfluenced by the water content.…”

“…Generally, baseline datasets to obtain the aforementioned mechanical parameters in tensile tests reveal widespread variation throughout the body [ 5 , 6 , 7 , 13 ]—an accepted “expectable” condition for human tissues. However, several factors such as the clamping quality [ 14 , 15 ], strain rate [ 16 ] and the mechanical and bio-physico-chemical tissue structure [ 5 , 17 , 18 ] impact the mechanical parameters to a varying extent ( Figure 1 ). Consequently, it remains unclear to date what the term “variation” describes in the context of mechanical parameters retrieved from human tissues related to their morphological characteristics.…”