MetallosisT84.-

Metallosis is the presence of metal debris caused, for example, by metal-on-metal (MoM) hip replacements. Metallosis is a rare but potentially serious complication following arthroplasty. It is generally associated with a metal-on-metal bearing couple, although isolated cases have been described with non-metal bearing couples. In case of fracture of the ceramic head/inlay, a change to a metal-polyethylene bearing couple is contraindicated.

Abrasion occurs with every artificial hip or knee prosthesis, regardless of the materials used. The organism can process a certain amount of abrasion without further consequences. However, if a defective prosthesis or a defectively installed prosthesis causes increased abrasion that the organism can no longer absorb, various clinical pictures develop, including dyschromia of the skin.

Especially with chromium, cobalt, titanium and molybdenum compounds, even the smallest amounts can lead to health problems due to the aggressiveness of the abrasion. These manifest themselves in symptoms such as cardiac arrhythmia, rashes, lack of concentration.

Metal-on-metal hip prostheses consist of a compound of chromium, cobalt, titanium and molybdenum.

A 62-year-old man presented because of a painless discoloration of the skin that developed in the scar area of a hip surgery. At the same time, he complained of chronic fatigue and increasing right hip pain. 7 years ago, after an endoprosthetic replacement surgery due to a ceramic head fracture, an endoprosthesis had been inserted using a combination of metal head and polyethylene inlay. After the revision surgery, the patient developed passive vision loss, hearing loss, and myocarditis.

Radiographically, there was deformity of the metal head and evidence of large radiopaque areas on the thigh.

Laboratory: Laboratory values of chromium and cobalt were elevated 600- and 1 000-fold, respectively. Intraoperatively, the entire thigh was abscess-like lined with metallic material and a dark-colored fluid. The thigh muscle and the polyethylene inlay were interspersed with ceramic particles. Surgery was performed with a change to a ceramic-on-ceramic bearing couple. Postoperatively, the metal ion levels as well as the accompanying symptoms were regressive.

1. Bradberry SM et al (2014) Systemic toxicity related to metal hip prostheses. Clin Toxicol (Phila) 52:837-847.
2. Hennig F et al. (1992) Nickel, chromium and cobalt concentrations in human tissue and body fluids of hip prosthesis patients. Journal of Trace Elements and Electrolytes in Health and Disease 6: 239-243.
3. Haddad FS (2013) Metal-on-metal. More questions than answers. The Journal of Bone and Joint Surgery 95-B: 1009-1010.