Bio-Environment-Induced Degradation and Failure of Internal Fixation Implants.
Internal fixations provide fast healing but their failure remains problematic to patients. Here, we report an experimental study in failure of three typical cases of metals: a bent intramedullary stainless steel nail, a broken exterior pure Ti plate, and a broken intramedullary stainless steel nail. Characterization of the bent nail indicates that those metals are vulnerable to corrosion with the evidence of increased surface roughness and embrittlement. Depredated surface of the Ti plate resulted debris particles in the surrounding tissue of 15.2 ± 6.5 μm in size. Nanoparticles were observed in transmission electron microscope. The electron diffraction pattern of the debris indicates a combination of nanocrystalline and amorphous phases. The failure mode of the broken nail made of stainless steel was found to be fatigue initiated from the surface. This study clearly shows the biological-attack induced surface degradation resulting in debris and fatigue. Future design and selection of implant materials should consider such factors for improvement.
Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA. zhouyansdu@gmail.com.
Yan
Y
Zhou
Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA. lukeallynperkins@gmail.com.
Luke A
LA
Perkins
Department of Orthopedic Trauma, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China. wanggd1986@163.com.
Guodong
G
Wang
Department of Orthopedic Trauma, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China. sdgkxh@aliyun.com.
Dongsheng
D
Zhou
Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA. hliang@tamu.edu.|Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA. hliang@tamu.edu.
Hong
H
Liang
debris particles; failure mechanisms; internal fixation; microhardness; potentiodynamic polarization scans; stainless steel; surface degradation; surface roughness; titanium