Retrospection shows allergy to metal implants in knee or hip replacements could be minimized by dermatogists and surgeons working together.

Team@CMHF

Preoperative skin patch testing for metal allergy influenced treatment planning in two-thirds of a small cohort of patients scheduled to receive metal-containing prosthetic devices, a retrospective chart review showed.

All 21 patients with positive tests received allergen-free prostheses and had no complications associated with hypersensitivity.

Post-implantation patch testing led to prosthesis removal in 10 additional patients, and six had resolution of hypersensitivity-associated symptoms.

“The findings of this study support a role for patch testing in patients with a clinical history of metal hypersensitivity before prosthetic device implantation,” Natasha Atanaskova Mesinkovska, MD, PhD, of the Cleveland Clinic. “The decision of whether to remove an implanted device after positive patch test results should be made on a case-by-case basis, as decided by the surgeon and patient,” they said.

The author of an accompanying editorial cautioned that “the patch test is a cutaneous test that does not recreate the environment in which the metal resides.”

Patch tests offer a means to identify patients at potentially increased risk of a hypersensitivity reaction to a metal implant, but the extent to which the results might influence surgeons’ decision making has remained unclear.

Mesinkovska and colleagues searched medical records for patients who had skin patch tests for contact allergy associated with orthopedic implants from 2003 to 2010. They identified 72 patients, 31 of whom had preoperative tests and 41 who had postoperative tests.

The authors reported that 21 patients tested preoperatively had positive results.In all 21 cases, the surgeon altered the original treatment plan and used an allergen-free implant. None of the patients had complications that could be attributed to hypersensitivity.

In the postoperative group, pain at the site of implant was the most common reason for skin patch testing .The metals most often associated with positive skin patch tests were nickel, cobalt, palladium, and chromium. No patient exhibited sensitivity to gold.

Those patients who underwent implant revision, all had symptom alleviation. “The study confirms the need for surgeons and dermatologists to work together and establish guidelines with a goal to identify patients who would benefit from revisions of previously implanted metal,” the authors wrote.

Mowad agreed, pointing out that “the dermatologist who patch tests must set realistic expectations for the patient and referring physician alike.”

The authors argued that “patch testing remains a standard for evaluating patients with suspected metal allergy. However, it may not always result in a diagnosis. We acknowledge the lack of agreement on which specific allergens, especially which metal salts, should be used for patch testing when devising the prosthesis trays.”

Ref: http://www.medpagetoday.com/Surgery/Orthopedics/312