Metal Allergy

• most common sensitizers are: nickel, cobalt, and chromium
• Stainless steel and cobalt-chromium alloys contain the above sensitizers.
• Titanium and titanium alloys generally do not contain the above sensitizers.
• People with a history of allergies to cobalt, chromium or nickel generally are not sensitive to titanium or its common alloys. (Ti-6AL-4V)
• Metal allergy may affect 10-15% of the population (Hallab N, JBJS 2001;83A:428). Prevalence may be increasing (Thyssen JP, Contact Dermatitis 2007;57:287).

Testing

• Patients with a potential metal sensitivity should be seen by a dermatologist or allergist for testing prior to any orthopedic implant.
• Dermatologist generally use testing kits such as, T.R.U.E Test Patch Test for testing. (www.truetest.com or www.allerderm.com, 800-365-6868)

TKA

• Patients with metal allergy should be treated with a modular titanium or all poly tibial component and an oxidized zirconium femoral component. Titanium has a propensity for metallosis and is not suitable for the articulating portions of the components. (Laskin RS, CORR 2003;416:191).

References

• Hallab N, JBJS 2001;83A:428
• Thyssen JP, Contact Dermatitis 2007;57:287