Metallosis

Metallosis is the build-up of metal debris in the tissues around a joint implant. It is most associated with metal-on-metal hip replacements, where the metal ball and cup rub together, and with some hip designs that have a metal connection between the head and stem. The debris can stain tissue gray or black, trigger inflammation, and kill surrounding tissue and bone.

The FDA calls the local response to metal particles around an implant an adverse local tissue reaction, and describes the broader local and body-wide responses as an adverse reaction to metal debris. According to the FDA, that soft tissue damage can lead to pain, implant loosening, device failure, and revision surgery, and patients with a progressing reaction may be considered for earlier revision to prevent more damage. Doctors may use blood tests for cobalt and chromium ions and imaging such as MRI or ultrasound to look for fluid collections and tissue damage.

Symptoms can include new or worsening pain in the hip, groin, or thigh, swelling, a grinding or clicking sensation, and trouble walking. Some patients report symptoms outside the joint that doctors link to high metal levels in the blood, though these are less common.

In litigation, a documented diagnosis of metallosis, especially one found during revision surgery, is often key evidence that an implant failed because of its design. Operative reports, pathology findings, and metal ion test results are the records attorneys typically ask for. See the metal-on-metal hip implant entry, and our guides on multidistrict litigation and how to sue a company.