Allocation of nonbirefringent wear debris: Darkfield illumination associated with PIXE microanalysis reveals cobalt deposition in mineralized bone matrix adjacent to CoCr implants

Abstract

Abrasive joint replacement material that accumulates in the tissue induces reciprocal effects between prosthesis material and organism. Since the limitations of brightfield and polarized light microscopy for foreign body analysis are well known, a method was applied that ensures the detailed histological assessment of nonbirefringent particles in periprosthetic soft and hard tissue. Cemented and cementless interface regions of five selected autopsy hip implant cases (2 x Endo-Modell Mark III, LINK, 1 x St. Georg Mark II, LINK, Germany; 2 x Spongiosa Metal II, ESKA, Germany) were viewed under darkfield illumination and subsequently analyzed with proton-induced X-ray emission (PIXE). Eight autopsy cases without implants served as controls. Using darkfield illumination technique, metallic particles became visible as luminous points under the microscope. The majority of particles in the samples from the cemented cases were degradation products of radiopaque bone cement. There was minimal evidence of metallic alloy particles in the soft tissues. However, a considerable quantity of heavy metal cobalt (Co) was found in the periprosthetic mineralized bone tissue, which was not observed in the controls. The periprosthetic concentration of cobalt ranged from 38 to 413 ppm. The findings demonstrate a correlation between cobalt concentration, time since implantation, and distance from the implant. Darkfield microscopy associated with PIXE enables a detailed histological assessment of metal particles in the tissue. In an effort to optimize biomechanics, implant design and implantation techniques, the contamination of soft and hard tissue with heavy metal degradation products deserves similar attention in terms of alloy assortment.

Co–Cr–Mo alloy particles induce tumor necrosis factor alpha production in MLO-Y4 osteocytes: A role for osteocytes in particle-induced inflammation

“…However, Busse et al successfully detected considerable quantity of heavy metal cobalt in the peri-prosthetic mineralized bone tissue. [3] In addition, the mechanism for osteocytes to recognize/sense the Co-Cr-Mo alloy particles is unknown and needs further investigation.…”

Particulate and ion forms of cobalt–chromium challenged preosteoblasts promote osteoclastogenesis and osteolysis in a murine model of prosthesis failure

“…28–30 One of the researches reported the higher metal ion concentrations around prostheses compared to urine, organs and serum levels by X-ray emission microanalysis. 31 It is therefore estimated that local Co(II) levels may be as high as 0.50 – 1 mM, implying that the concentrations utilized in this study were within a clinically significant range. 32 Further, our preliminary in vitro test 33 clearly suggested that particles (5 mg/ml) or ions (1mM) resulted in ubiquitous cell death compared to debris-free controls, while particles﹤0.15 mg/ml or ions ﹤32 μM did not show any influence on preosteoblast proliferation.…”

Cobalt deposition in mineralized bone tissue after metal-on-metal hip resurfacing: Quantitative μ-X-ray-fluorescence analysis of implant material incorporation in periprosthetic tissue

“…For histological assessment, sections of 4 µm thickness were cut using the microtome and stained using standard staining techniques (von Kossa, Goldner trichrome, Toluidine blue). The stained sections were analyzed by bright and dark field microscopy (Axioplan II, Zeiss, Germany).…”

“…Formation, transport, and accumulation of metallic wear particles are associated with hip joint arthroplasty . Increased concentrations of circulating metal degradation products derived from orthopedic implants may have deleterious biological effects over the long term that warrant investigation .…”

“…Although there is less bone resection with a changed biomechanical loading at the femoral site compared with a standard hip replacement and the majority of patients that have received metal‐on‐metal based hip resurfacing appear to be in good health, a number of questions remain regarding the long‐term effects of exposure to the articulation material. Dark field microscopy and particle‐induced X‐ray emission (PIXE) have revealed metal particles over large areas in the soft tissue and cobalt deposits locally in the mineralized bone tissue surrounding total joint implants . A correlation between cobalt concentration, time since implantation, and distance from the implant has been observed in cases with metal‐on‐polyethylene (MoP) bearings …”