International Journal of Risk & Safety in Medicine - Volume 8, issue 1
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The International Journal of Risk and Safety in Medicine is concerned with rendering the practice of medicine as safe as it can be; that involves promoting the highest possible quality of care, but also examining how those risks which are inevitable can be contained and managed.
This is not exclusively a drugs journal. Recently it was decided to include in the subtitle of the journal three items to better indicate the scope of the journal, i.e. patient safety, pharmacovigilance and liability and the Editorial Board was adjusted accordingly. For each of these sections an Associate Editor was invited. We especially want to emphasize patient safety. Our journal wants to publish high quality interdisciplinary papers related to patient safety, not the ones for domain specialists. For quite some time we have also been devoting some pages in every issue to what we simply call WHO news. This affinity with WHO underlines both the International character of the journal and the subject matter we want to cover. Basic research, reports of clinical experience and overviews will all be considered for publication, but since major reviews of the literature are often written at the invitation of the Editorial Board it is generally advisable to consult with the Editor in advance. Submission of news items will be appreciated, as will be the contribution of letters on topics which have been dealt with in the journal.
Abstract: For the evaluation of newly developed orthopaedic implantations, it is of utmost importance to collect all available information with respect to the behaviour of the implant. Retrieval analysis of well-functioning implants (post-mortem) and of failures (during revision) may give very valuable information with respect to short term reactions of the organism to the implant. In this case, bone reactions were studied around a titanium, hydroxyapatite (HA) coated Osteonics bipolar hip prosthesis, which was revised for severe mid thigh pain four years after implantation. Scarce remnants of a coating-like material on the surface of the prosthesis were found after inspection…of the retrieved prosthesis using a dissecting microscope. Histology of these remnants and of the bony side of the bone-HA interface, failed to reveal any remnants of a HA coating. Trabecular bone which closely followed the contour of the prosthesis was found at the bone-prosthesis interface. Facing the prosthesis, this trabecular bone was mainly immature callous bone. At other locations, where mineralized bone faced the prosthesis, many small dark titanium wear particles were found. Similar particles were found in macrophages in the intertrabecular medullary space. Polyethylene wear particles were specifically located in macrophages in a soft tissue interface at more distal levels along the stem of the prosthesis. Although the observations presented in this case cannot be generalized, it clearly shows that the HA coating layer had completely disappeared after four years. More detailed retrieval studies and longer clinical follow-up studies are needed before a final evaluation of the behaviour of HA coatings and long term fixation of HA-coated prostheses can be made.
Abstract: Retrieval analysis of cardiovascular implants closes the product lifecycle. Currently, the development of devices is driven by technical innovation. However, many implanted devices are outlived by their carriers. Second, the public demands higher resistance capabilities against material degradation, better biocompatibility, and maximum safety. Analysis of the functional and structural status of retrieved implants contributes largely to our knowledge. To make implant retrieval meaningful, it is imperative to agree on a research focus and on standards for implant preservation and the actual analysis. Second, easy patient tracking and financial and scientific incentives are indispensable.
Abstract: Metal ion release was assessed in 31 patients with loosening of total hip replacements (THR). Three types of alloys were used for these prostheses: stainless steel (9/31), Ni-Cr-Mo (5/31) and Co-Cr (17/31). The exposure periods were from 2 to 15 years. Intracellular deposits were observed in macrophages, fibroblasts, histiocytes and numerous multinucleated giant cells. X-ray microprobe analyses by energy dispersive spectrometry (EDS) on ultrathin sections revealed the presence of elements contained in the alloys (Ni, Cr, Fe, Mo) and of additional elements, in particular P, CI, Ca and S. Co was only detected in wear particles. Metal distribution in…tissues and body fluids was related to the alloys used. Stainless steel THR induced the lowest metal concentrations, Ni-Cr-Mo alloys showed high increases of Ni and Cr. Co-Cr alloys induced very high Co levels: 100- to 400-fold concentrations in body fluids and 600- to 1000-fold concentrations in tissues with respect to normal upper levels. The metal clearing was studied in three patients with Co-Cr-THR. Two years after removal, only Ni reached normal values. The sometimes alarming high concentrations should lead to a systematic follow up and surveillance of patients.
Keywords: Nickel, cobalt, chromium, THR-loosening, body fluids, tissues elemental analyses, metal clearing