The new report has led to some European medical researchers to call for a “critical reconsideration” of the use of metal alloys in artificial hips. The risk arises because chromium and cobalt ions, from the metal-based medical implants, can be released into the human body. These metal ions pose a risk to bone formation by interfering with the predecessors of bone-forming cells.
The use of metal implants became popular in the 1990s, when there was a move away from the use of ceramic based materials.
The research, conducted at Charité – Universitätsmedizin Berlin and DRK Klinikum Westend, undertook examinations of tissues, fluids and bone marrow, from selected patients, in the region where metal-on-metal hips had been implanted. These bio-samples were screened for levels of chromium and cobalt, in the form of metal shards.
The research troublingly found that metal shards had, in most cases, gravitated towards bone marrow. Further tests revealed that the shards had exerted an adverse effect, by inhibiting bone mineralization.
The findings were replicated in cell culture studies, where human cells were exposed to metal ions. The same inhibitory effects were observed, indicating that the chromium and cobalt ions exhibited a deleterious effect.
Commenting on the study findings, Dr. Anastasia Rakow, who led the study, told medical website QMed: “Local exposure assessment represents a significant contribution in our quest to better understand the biological responses to metal wear, and helps to identify causations of implant failure.”
It is thought the release of ions relates to multiple factors, although the inherent nature of the metals are the prime factor. More research into this will be needed to determine the actual patient exposure risk. If there was evidence that the ions enter the circulatory system, the risks would be higher still.
The news caused one Twitter user WaiO (@WaiO38) to message: ” Metal-on-Metal Implants Are Really Scary.”
The findings have been published in the journal Biomaterials. The research paper is titled “Influence of particulate and dissociated metal-on-metal hip endoprosthesis wear on mesenchymal stromal cells in vivo and in vitro.”
