Thank you for your inquiry.
The role of metal allergy, including nickel, in problems occurring with knee replacements and other metal prostheses is a constantly evolving area. We have had numerous entries on our website regarding potential problems with metal allergy in relation to metal prostheses and implants. These will all be of interest to you, and I suggest that you go to our “Ask the Expert” website and enter “implants” into the search box. You will find many entries. These entries discuss the role of patch testing and in vitro tests in discerning whether or not a patient has metal allergy causing problems with their implant or prosthesis. As noted, these entries should be very helpful to you.
In the meantime, in direct answer to your questions:
1. Nickel is contained in some, but not all, implants. The only way to tell whether the specific implant in question contains nickel is to obtain this information from the manufacturer of the implant in question. For your interest, I have copied below a link to a website which discusses in detail the various metal contents of implants. Also, there are nickel-free implants.
Metallic Biomaterials of Knee and Hip - A Review
Trends Biomater. Artif. Organs, Vol 24(1) 69-82, 2010
2. The role of metal sensitivity in causing postoperative problems with knee replacements, as noted, is evolving. The previous entries on our website discuss this issue in detail, and a more recent review (abstract copied below) will help you explore this issue further. But it appears that metal sensitivity can play a role in causing problems with implants.
3. Patch testing can discern whether or not the patient is allergic to nickel, but of course does not establish a definite cause and effect relationship between the problem with an implant and nickel allergy. However, the absence of a positive patch test will be of more value in ruling out such a relationship.
Thank you again for your inquiry and we hope this response is helpful to you.
Contact Dermatitis. 2012 Feb;66(2):55-62. doi: 10.1111/j.1600-0536.2011.01970.x. Epub 2011 Sep 29.
Metal allergy and second-generation metal-on-metal arthroplasties.
Cousen PJ, Gawkrodger DJ.
Department of Dermatology, Royal Hallamshire Hospital, Sheffield S10 2JF, UK.
There are concerns about the induction of metal allergy with second-generation metal-on-metal prostheses, and the role that this may play in the development of complications such as 'pseudotumours' or failure of the implant. In this review, we attempt to set out the current knowledge on this subject. From a review of the literature, it is apparent that the first-generation metal-on-metal replacement hips did cause metal sensitization, and that joint failure was associated with this, although it is still not clear which one led to the other. Highly engineered second-generation metal-on-metal arthroplasties used in joint resurfacings are now increasingly employed. Several studies have recently shown an association between metal sensitization and peri-implant hypersensitivity reactions and implant loosening and failure, although the overall risk appears to be low. The pragmatic approach adopted by most contact dermatologists for patients known to be allergic to nickel, cobalt or chromium and who require joint replacement is to recommend prostheses made of titanium-based alloys. Patch testing continues to be a useful tool as laboratory investigations for metal hypersensitivity continue to emerge. The development of guidelines on the management of patients receiving metal-on-metal arthroplasties suspected of being metal-allergic is desirable.
Phil Lieberman, M.D.