The effect of patch testing on surgical practices and outcomes in orthopedic patients with metal implants.

OBJECTIVE To determine the effect of patch testing on surgical decision making and outcomes in patients evaluated for suspected metal hypersensitivity related to implants in bones or joints. DESIGN Medical chart review. SETTING Tertiary care academic medical center. PARTICIPANTS All patients who had patch testing for allergic contact dermatitis related to orthopedic implants. INTERVENTION Patch testing. MAIN OUTCOME MEASURES The surgeon's preoperative choice of metal implant alloy compared with patch testing results and the presence of hypersensitivity complications related to the metal implant on postsurgical follow-up. RESULTS Patients with potential metal hypersensitivity from implanted devices (N = 72) were divided into 2 groups depending on timing of their patch testing: preimplantation (n = 31) and postimplantation (n = 41). History of hypersensitivity to metals was a predictor of positive patch test results to metals in both groups. Positive patch test results indicating metal hypersensitivity influenced the decision-making process of the referring surgeon in all preimplantation cases (n = 21). Patients with metal hypersensitivity who received an allergen-free implant had surgical outcomes free of hypersensitivity complications (n = 21). In patients who had positive patch test results to a metal in their implant after implantation, removal of the device led to resolution of associated symptoms (6 of 10 patients). CONCLUSIONS The findings of this study support a role for patch testing in patients with a clinical history of metal hypersensitivity before prosthetic device implantation. The decision on 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.