Summary
Orthopedic implants may be either
static, such as rods and screws, or dynamic, such as an artificial
hip or knee joint. Most joint implants now have a metal-to-plastic
interface, although metal-to-metal interfaces are making a
comeback, due to potentially superior wear resistance.
Metal allergy is very common, with nickel (Ni) being the single
most common allergen of all those used in most published patch-test
series[1]. Cobalt and chromium (Cr) are common allergens as well.
Titanium and molybdenum (Mo) are rarely reported as allergenic, but
are not tested with on a routine basis.
The following questions can then be raised:
1) Does orthopedic metal implantation lead to an increase in metal
allergy?
2) Are patients with metal allergy who undergo an implant likely to
develop dermatitis postimplantation?
3) Are patients with metal allergy more likely to develop problems
with the implant (failure to heal, chronic pain, loosening,
etc.)?