Biomechanical Implant Fatigue Tests

Biomechanical Implant Fatigue Testing Laboratory

Key concepts for medical device design include biomechanics, biocompatibility, and biofunctionality. Our laboratory will review biomechanical tests at EUROLAB, mechanics, bone and mechanical testing of a sample biological tissue used in the development of medical devices and equipment.

Medical device design requires extensive testing. Biomechanics, which demonstrates the mechanical properties of biological tissues such as bone, tendon, ligaments and muscles, requires research and testing of biological tissues under various loading conditions. Although biomechanics applies engineering principles to biological systems, it also requires careful analysis of biological tissue. A medical device can be accurately verified only if the properties of the tissue it is altered and the tissue it is in contact with are known.

  • The mechanical properties of tissues vary with age and varying conditions including biological and environmental factors. In addition, most tissues are composite and viscoelastic materials, ie their mechanical properties vary from one point to another.

Bones, the building blocks of the skeletal system, are composite materials consisting of both liquid and solid phases. Water, which may be present in the organic matrix or in the channels and voids, constitutes 25% of the total bone weight. Solid phases give the bones their rigid structure as well as flexibility and flexibility.

Bones can repair and reshape themselves, and their mechanical properties depend on the changes experienced by the body. It is also important to note that the composition and, as a result, certain characteristics of bone vary according to age, sex, bone and bone tissue types, and other factors.

There are numerous terms for classifying bone. This article will briefly cover two tissues that make up the bones: cortical or compact bone tissue and spongy or spongy bone tissue. The dense cortical bone tissue is linearly elastic and forms the outer cortex of the bones and diaphysis. The fibrous layer covering all bones (except the joint surfaces) is called the periosteum. Spongy bone tissue is an inhomogeneous network enclosed by cortical bone.

Bones are defined as cortical or spongy depending on the degree of porosity and organization. Although the degree of porosity may vary over time or with disease and altered loading, the spongy bone will have higher porosity than the cortical bone when distinguishing between spongy and cortical bones.

To properly analyze the material properties of the bone, it is necessary to discuss the mineral content. When the bones have a higher mineralization, they exhibit a higher final tensile strength (UTS) and Elasticity Module. In contrast, high mineralization will generally reduce hardness. Cortical bone shows a higher modulus of elasticity than cancellous bone and has the most suitable properties for resistant torque. On the other hand, the cancellous bone has a greater capacity to store energy, so it can maintain much higher stresses than failure in addition to resisting high compression and shear forces.

Biomechanical Testing

Biomechanical assessments for medical devices include the ability of an implant to withstand tensile, compressive and shear forces, variations and degrees of freedom, and mechanical properties of the device, such as Elastic Module, yield strength, and failure elongation. Materials such as metals and alloys, ceramics and polymers are used to develop medical devices.

Metallic implants have a regular, 3D crystal structure and are mainly used for load bearing (eg hip and shoulder implants, fixation devices). Depending on the properties of the selected metal, highly reactive metallic surfaces that are resistant to surrounding tissues generally require further metallic processes or, where possible, the use of other biomaterials on the outer surface. On the other hand, ceramics are non-metallic and non-organic, with the highest compressive strength, but exhibit poor tensile properties. The most common use of ceramics is dental implants. Polymers are organic materials consisting of repeating units. Advantages include controlled degradation rates and easy production.

You can work with our laboratory EUROLAB for biomechanical tests.