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Risks of metal allergy in joint replacement and how to manage them |
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Although the odd isolated case of metal allergy in orthopaedic implants has been documented, the true prevalence is unknown. Dr Joshua Jacobs, in his address at the American Academy of Orthopaedic Surgeons 2012 Annual Meeting, has stated that allergic symptoms seem to be more common in metal-on-metal total hip replacements. Allergic symptoms manifest as unexplained pain, stiffness, pseudotumours or necrosis, and may involve a rash. The symptoms disappear after the replacement has been removed, only to begin again after the replacement is reinserted. Skin patch testing in advance of implantation would not work, says Jacobs, because it would not truly represent what might occur deep in the tissues. In patients who have had metal-on-metal replacements, there is a correlation between their serum metal levels and metal sensitivity, determined by lymphocyte transformation testing (LTT). Patch testing and in vitro diagnostic tools need to be more robust, but can be useful in preoperative screening for patients with in vitro metal allergies with a history of reaction to jewellery. Source: American Academy of Orthopaedic Surgeons Allergy tests needed before knee hip or knee – 02/12 A retrospective study of the effect of patch testing on patients who are about to have joint replacements, and have a history of metal sensitivity has found that it is effective. However using patch testing to determine whether to remove an implant should be decided on a case-by-case basis by the surgeon and patient. Seventy-two patients with possible sensitivity to implants were divided into a group who had undergone pre-implantation patch testing (31 people) and post-implantation patch testing (41 people). Of the 31 who tested positive in pre-implantation patch tests, the surgeon then altered the implants of 21 to be non-allergenic. All of the 21 have had surgical outcomes free from hypersensitivity complications. Of the group of 41 who had post-operative patch testing, removal of the implant led to the resolution of hypersensitivity symptoms in 6 of the ten patients. The study was carried out by Dr Natasha Atanaskova Mesinkovska of the Cleveland Clinic, Ohio, USA. Source: Archives of Dermatology More miscellaneous articles on non-food allergy First published March 2012 |
