title: Failure analysis of sandwich-type ceramic-on-ceramic hip joints: A spectroscopic investigation into the role of the polyethylene shell component.
abstract: The mechanisms leading to systematic failure in modular acetabular components with a sandwich insertion (alumina/polyethylene/titanium) have been reconsidered in light of the newly collected Raman spectroscopic results. Raman assessments were conducted on the polyethylene shells, which belonged to a series of six failed sandwich implants with in vivo lifetimes ranging between 2 and 9yr. With only one exception, all implants commonly showed dislodgment of the polyethylene shell during radiographic analyses prior to revision surgery. The polyethylene shell slipped out of the backing titanium shell, while always remaining integer to the ceramic liner. Four implants fractured at the ceramic liners, but their fractures occurred according to distinctly different patterns, which could be rationalized and classified. The insertion of the polyethylene layer, originally conceived to reduce the rigidity of the ceramic-on-ceramic bearing and to prevent impingement between the ceramic liner rim and the femoral neck, played a role in implant failure with its initial (asymmetric) thickness reduction due to creep deformation (eventually followed by cup rotation and backside wear). The results of the present spectroscopic investigation suggest that a simplistic failure classification of the sandwich-type implant as a "ceramic fracture failure" could be misleading and might represent a confounding factor in judging about the reliability of modern ceramic implants.
authors: Department of Orthopaedic Surgery, Mie University, Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
authors: Shinya
authors: S
authors: Okita
authors: Department of Orthopaedic Surgery, Mie University, Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan. Electronic address: masahase@clin.medic.mie-u.ac.jp.
authors: Masahiro
authors: M
authors: Hasegawa
authors: Ceramic Physics Laboratory & Research Institute for Nanoscience, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto, Japan.
authors: Yasuhito
authors: Y
authors: Takahashi
authors: Ceramic Physics Laboratory & Research Institute for Nanoscience, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto, Japan.
authors: Leonardo
authors: L
authors: Puppulin
authors: Department of Orthopaedic Surgery, Mie University, Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
authors: Akihiro
authors: A
authors: Sudo
authors: Ceramic Physics Laboratory & Research Institute for Nanoscience, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto, Japan.
authors: Giuseppe
authors: G
authors: Pezzotti
mesh_terms: D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry*; D002516:Ceramics / Q000032:analysis / Q000737:chemistry*; D019544:Equipment Failure Analysis / Q000379:methods*; D006622:Hip Prosthesis; D008422:Materials Testing / Q000379:methods*; D020959:Polyethylene / Q000032:analysis / Q000737:chemistry*; D011475:Prosthesis Failure; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D001672:Biocompatible Materials; D020959:Polyethylene
keywords: Ceramic fracture; Ceramic-on-ceramic; Creep; Dislodgment; Raman spectroscopy; Total hip arthroplasty; Wear