Is Metal Hypersensitivity Testing Unnecessary?

A new review article has found that the existing literature does not support preoperative metal hypersensivity testing. The article, “Metal Hypersensitivity in Total Joint Arthroplasty,” appears in the December 2018 edition of JBJS Reviews.

Nima Eftekhary, M.D., study co-author and resident at the NYU Langone Department of Orthopaedic Surgery told OTW, “The available literature regarding metal hypersensitivity is sparse. The topic is controversial. In discussing this topic with our colleagues we noted that it was a polarizing one with many different opinions offered. In this context, we decided to look more in-depth at the available literature regarding metal hypersensitivity. Specifically, we reviewed the available literature for workup, differential diagnosis, and treatment options.”

“Perhaps the most important takeaway is that metal hypersensitivity is a topic in which significantly more research is required. Additionally, a painful total joint is most likely painful due to a number of other reasons.”

“We found no good data to support routine preoperative allergy testing or routine use of hypoallergenic implants. In a patient who has been worked up for a painful total knee without a clear etiology for pain, workup for metal hypersensitivity is a reasonable option. However, the best of these tests are expensive and not available at all centers.”

“First, we did not find enough evidence to support preoperative allergy testing, though we did come across interesting retrospective studies that demonstrated an increased revision risk in patients with positive allergy testing.”

“In patients with a history of nickel or metal allergy, hypoallergenic implants can be considered. However, the vast majority of patients with a known metal allergy do not develop a hypersensitivity-related issue with their arthroplasty. Cutaneous skin allergies occur through a different immune mechanism that the intra-articular immune reaction associated with metal hypersensitivity from total joint arthroplasty.”

“In the workup of a painful total joint without evidence of a clear etiology for pain, workup for metal hypersensitivity is reasonable. The most sensitive of the available tests is the lymphocyte transformation test (LTT). In a revision surgery for painful total joint arthroplasty due to metal hypersensitivity, hypoallergenic implants should be used. Ultimately, further research is warranted in this complex and controversial topic.”

“Surgeons at our institution are not routinely obtaining a preoperative workup for allergy nor routinely using hypoallergenic implants on primary total joint arthroplasty. Metal hypersensitivity should be considered in a painful total joint in which more common etiologies for pain have been excluded. Revision for metal hypersensitivity should strongly consider use of hypoallergenic implants if available. Further research is warranted.”