D2.273 - The frequency of metal sensitisation in patients who are about to undergo joint replacement

It is estimated that 10–15% of the general population has a metal allergy. This allergy can cause complications for patients who have received, or are due to receive, an artificial joint. The main objective of this study is to determine the frequency of sensitivity to metals and cements.

A retrospective, observational cohort study was conducted. We analysed patients who were referred to our unit from the Department of Traumatology and Orthopaedic Surgery at Hospital Clínico San Carlos for a metal allergy study prior to undergoing joint replacement surgery between 1 January 2023 and 30 March 2025. All patients’ clinical histories were recorded, and patch tests using a standardised metal battery were performed on all of them (table 1). The patch tests were read at 48 and 96 hours. The institutional ethical committee authorised the study (ref. 25/529-E).

Forty-one patients were included, primarily women (95.1%) with an average age of 72 years (standard deviation: 9.1 years). Notably, 35 patients (85.4%) had previously experienced contact dermatitis, presumably caused by costume jewellery. We found that 16 patients (39%) were not sensitised to any of the metals tested, and none of them were sensitised to cements. Of those who were sensitised, the main sensitising agents were nickel (51.3%, positive patch test to nickel (II) sulfate hexahydrate 5% pet.), palladium (43.2%, positive patch test to palladium (II) chloride 2% pet. and/or sodium tetrachloropalladate (II) hydrate) and chromium (12%, positive patch test to potassium dichromate 0.5% pet.). Interestingly, frequent cosensitization between nickel and palladium was observed in 13 cases (52%).

The most common sensitisations found in patients who are about to undergo joint replacement surgery are to nickel, palladium and chromium. The most common co-sensitisation in our cohort is to nickel and palladium. The clinical implications of these sensitisations following joint implantation remain to be elucidated.