Metal-on-metal bearings total hip arthroplasty: The cobalt and chromium ions release concern

Abstract

With certain concerns recently reported on metal-on-metal bearing couples in total hip arthroplasty, this study's objective is to review the current knowledge concerning release of metal ions and its potential consequences. Each metal-on-metal implant presents different tribological properties. The analytical techniques for metals are accurate and the Co ion rates seem acceptable up to 2 μg/L. A delayed type IV hypersensitivity reaction (atypical lymphocytic vasculitis-associated lesion [ALVAL]) may be the source of arthroplasty failure. Idiosyncratic, it remains unpredictable even using cutaneous tests and apparently is rare (0.3%). Today, there are no scientific or epidemiologic data supporting a risk of carcinogenesis or teratogenesis related to the use of a metal-on-metal bearings couple. Solid pseudotumors nearly exclusively are observed with resurfacing procedures, carrying a high annual revision rate in women under 40 years of age, occurring particularly in cases of acetabular malposition and with use of cast molded Cr-Co alloys. Osteolysis manifests through complete and progressive radiolucent lines or through cavitary lesions stemming from ALVAL-type alterations or impingement problems or implant incompatibility. The formation of wear debris exceeding the biological tolerance is possible with implant malposition, subluxation, and jamming of the femoral head in cases of cup deformity. Moreover, each implant presents different metal ion production; assessment of their performance and safety is required before their clinical use. With the knowledge available today, metal-on-metal bearing couples are contraindicated in cases of metal allergies or end stage renal dysfunction and small size resurfacing should cautiously be used.

Cementless Total Hip Arthroplasty With Metasul Bearings Provides Good Results in Active Young Patients: A Concise Followup

“…Results The 15-year survivorship (33 hips at risk) for revision for any reasons (four hips) and for aseptic loosening (one hip) was 96% (95% confidence interval [CI], 81%-99%) and 99% (95% CI, 85%-99.9%), respectively. The median Merle d'Aubigné-Postel score remained stable at 17 points (range, [10][11][12][13][14][15][16][17][18]. Thus far, we have not observed pseudotumors or other adverse reactions to metallic debris.…”

Les prothèses de hanche au cobalt sont-elles dangereuses ?

“…Étant soumises à l'usure et à la corrosion, les PHMM présentent l'inconvénient de libérer des particules métalliques capables de part leur petite taille, de se disséminer dans l'organisme du porteur par l'intermédiaire de la lymphe et du système vasculaire [1,4,6]. La quantité d'éléments libérés est très variable.…”

“…D'autres manifestations indésirables peuvent survenir comme, par exemple, une ostéolyse, un épanchement articulaire, une nécrose des tissus environnant la prothèse [6,7]. Ces effets toxiques à court terme ne sont mis en évidence qu'en cas de cobaltémie supérieure à 10 μg/l [18].…”

“…En raison du passage transplacentaire du cobalt au cours de la grossesse, le risque pour la descendance est suspecté même s'il n'est pas prouvé. Aucune étude à ce jour n'a mis en évidence d'effets indésirables chez des nouveau-nés de mères porteuses de PHM [6,12,19,27]. Chez les insuffisants rénaux, une accumulation du cobalt pourrait survenir en raison de son défaut d'élimination par les reins.…”

Hip resurfacing arthroplasty versus large-diameter head metal-on-metal total hip arthroplasty: comparison of three Designs from the Finnish Arthroplasty Register

“…Recently, increased numbers of MoM bearing surface wear complications have been detected (5)(6)(7). Concerns exist regarding the consequences of prolonged exposure to increased metal-ion levels, such as adverse reaction to metal debris (ARMD) (8,9). It has been stated that although HRAs and LDH MoM THAs have the same bearing characteristics, wear and corrosion at the junction between the femoral neck and the adapter sleeve, as well as the open femoral head design, are suspected to be responsible for the additional load of metal-ion release (10).…”