Image: Macroscopic (L) and scanning electron microscopy (R) images of a titanium fiber plate (Photo courtesy of Shinshu University).
A new study claims that titanium fiber plates, unlike conventional ones, do not cause bone embrittlement, which could eliminate the need for plate extraction and the associate surgical risks.
Developed at Shinshu University (Matsumoto, Japan) the new plates are formed by molding titanium fibers into plates by simultaneously applying compression and shear stress at normal room temperature. As a result, the titanium fiber plates show a nearly identical measurement of stiffness (Young's modulus) as that of natural bone, compared to conventional plates, which have a Young's modulus four to 10 times higher. A difference in stiffness levels can eventually causes bone embrittlement due to stress shielding.
But as the titanium fiber plates have an elastic modulus similar to that of bone cortex, stress shielding will not occur, even when the plate lies flush against the bone's surface. In addition, the titanium fibers can form a porous scaffold structure suitable for cell adhesion. In rat studies, osteoblasts combined with the titanium fiber plate were better able to facilitate bone tissue repair than the conventional titanium plate when implanted into bone defects. The study was published on January 25, 2018, in Advanced Materials.
“Our titanium fiber plates, unlike conventional titanium plates are prepared by compressing titanium fibers at normal room temperature into plates without changing the fiber shape,” said lead author Takashi Takizawa, MD, of the department of orthopedic surgery at the Shinshu University School of Medicine. “They can compensate for the major drawback of conventional titanium plates, and find application in a range of fixation and bone tissue repair uses at various sites of the body.”
Most commonly used to hold bones in place while they heal, titanium plates are erosion resistant and strong enough to hold the mending bones in place. But in many cases titanium plates are removed after the healing has finished, as they can cause stress shielding leading to bone embrittlement after close contact with the bone for prolonged periods. In contrast, titanium fiber plates may be permanently placed, without removal surgery.