International Journal of Risk & Safety in Medicine - Volume 8, issue 1

Authors: Buma, Pieter

Article Type: Research Article

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. Show more

DOI: 10.3233/JRS-1996-8120

Citation: International Journal of Risk and Safety in Medicine, vol. 8, no. 1, pp. 111-117, 1996

Authors: de Mol, Bas A.J.M.

Article Type: Research Article

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.

Keywords: retrieval analysis cardiovascular implants

DOI: 10.3233/JRS-1996-8121

Citation: International Journal of Risk and Safety in Medicine, vol. 8, no. 1, pp. 119-123, 1996

Authors: Hildebrand, H.F. | Laffargue, P. | Decoulx, J. | Duquennoy, A. | Mestdagh, H.

Article Type: Research Article

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. Show more

Keywords: Nickel, cobalt, chromium, THR-loosening, body fluids, tissues elemental analyses, metal clearing

DOI: 10.3233/JRS-1996-8122

Citation: International Journal of Risk and Safety in Medicine, vol. 8, no. 1, pp. 125-134, 1996