Metal hypersensitivity in trapeziometacarpal arthroplasty: A systematic pattern of progression

Metal hypersensitivity is a rare and often underestimated complication, as shown by the small number of published studies, particularly concerning the upper limbs and the hand. However, the increase in the annual number of trapeziometacarpal arthroplasties underlines the importance of better understanding of this problem. We performed a study based on data from the revision of trapeziometacarpal prostheses to assess the incidence of this complication and to define a sequence of radiological changes to detect metal hypersensitivity. This single-center retrospective study included 37 patients operated on between January 2014 and November 2023 for revision of trapeziometacarpal prosthesis. Ten (27%) had no clearly identified cause of failure. For these 10 patients, we analyzed clinical data and postoperative X-rays. In the 11 revision arthroplasties, 2 patients had no symptoms or radiographic signs suggestive of allergy. Six patients had a-posteriori diagnosis established by allergy testing, which also identified 2 additional patients, for a total of 8 patients (21% of the initial cohort). In these cases, there was systematic metaphyseal osteolysis of the first metacarpal between 15 days and 1 month after implantation. Clinically, most patients had an asymptomatic period of 2 weeks to 1 month before onset of symptoms and osteolysis, often accompanied by local inflammation. This study found a reproducible pattern of progression, characterized by the appearance of radiographic signs of osteolysis in the first month, followed by clinical deterioration. Although this course is strongly suggestive of a metal hypersensitivity, it is crucial not to exclude the possibility of an infectious cause, which should always be considered.