NAPA, CALIF. – There is little risk that patients with orthopedic metal implants will have a skin reaction or joint pain from the device, said Dr. Joseph F. Fowler.
"I do patch test patients ... who have concerns about a metal allergy or are going to have an implant. I tell them if they have a positive patch test, they may have a skin reaction," said Dr. Fowler. However, there is a small chance they will have a cutaneous reaction, and a smaller chance they will have problems with the joint.
Dr. Joseph F. Fowler
Metals used in orthopedic implants include stainless steel, which is composed of an iron-chromium alloy plus nickel and molybdenum, and sometimes a little chromium and titanium; nitinol (55% nickel and 45% titanium); vitallium (iron cobalt plus chromium 30% and molybdenum 5%); and titanium. Two of the four metals contain nickel, a common contact allergen, noted Dr. Fowler, a dermatologist at the University of Louisville (Ky.).
When it comes to joint pain from implants, findings from a small German study of 15 patients showed that levels of the inflammatory marker interleukin-17 (IL-17) were increased in only those patients with nickel containing replacement joints who both had a positive patch test to nickel and complaints of joint pain. IL-17 levels were not increased in patients with a positive patch test to nickel who did not complain of joint pain (Contact Dermatitis 2010;63:15-22).
In an unpublished study, Dr. James Taylor of the Cleveland Clinic found that 60% of a small group of patients (10) with a metal implant who had a positive patch to metal experienced resolution of joint pain after the metal was replaced. "There is getting to be more and more of a suggestion that metal allergies and joint problems do go hand in hand," said Dr. Fowler.
If you just had to guess what would be the best material to put in a patient who with a chance of a metal allergy, titanium is the best bet, he said. "It comes down to a medical legal question. Will doctors and patients accept a small amount of risk if there is an implant that is better than titanium?"
He said that he will patch test patients if requested by the physician who will be performing the implant surgery, but it is not normally done because there is less than a 1% chance that even if they do have a positive patch test to metal, dermatitis will occur. There have been reports, although rare, that a metal allergy may cause joint failure, but prospective studies are needed, he said.
Dr. Fowler reported financial conflicts of interest with multiple pharmaceutical companies.