Correlation between metal allergy and treatment outcomes after ankle fracture fixation.

PURPOSE To determine correlation between metal hypersensitivity and long-term foot and ankle function and pain after internal fixation using stainless steel implants. METHODS 60 men and 46 women (mean age, 47 years) who underwent internal fixation for ankle fractures completed a questionnaire 13 to 38 (mean, 26) months after surgery to assess their existing medical condition, history of metal hypersensitivity, problems and outcome of the implant (revision or removal), and the American Academy of Orthopaedic Surgeons (AAOS) foot and ankle score. A subset of 12 men and 15 women then underwent patch testing for metal hypersensitivity to molybdenum, chromium, iron, manganese, and nickel. Patients with positive and negative reactions were compared. RESULTS 21 of the 106 patients underwent removal of the metal implants. The AAOS score was not associated with any of the variables, except for a history of metal hypersensitivity from dental implants and irritation around the surgical scar. Multiple linear regression analysis showed that only irritation around the surgical scar remained associated with poorer AAOS scores. Five of the 27 tested patients had a positive reaction. The mean AAOS scores did not differ significantly between patients with positive and negative reactions (34 vs. 31, p=0.73). Gender was not associated with the test results (p=0.63). None of the 5 patients with a positive reaction underwent revision surgery or reported any history of asthma or metal hypersensitivity. Of the 27 patients, one of the 8 who reported itching, irritation, redness or rash around the surgical scar had a positive reaction, compared to 4 of 19 patients who reported no such symptoms (p=1). Two of the 27 patients reported development of eczema after fixation, one of whom had a positive reaction. Only one of the 27 patients reported a history of metal hypersensitivity to jewellery, but had a negative reaction.. CONCLUSION Neither a history of metal hypersensitivity nor positive patch testing correlated with poor outcomes after internal fixation for ankle fractures using stainless steel implants.