Detection of total hip prostheses at airport security checkpoints.

Background: There have been several reports regarding airport security checks using arched metal detectors in patients with orthopedic implants and/or joint replacement surgery. Implants of different sizes and/or materials are used in total hip arthroplasty (THA), but there have been no reports regarding differences in detection rates between different types of THA implants and materials. We examined detection rates by airport metal detectors among THA patients with different implants.

Methods: We selected 1684 patients from regular outpatients at our hospital from June to December 2016. A questionnaire elicited responses regarding usage of airplanes, flight type (domestic/international), and detection by airport metal detectors. Data were investigated according to unilateral/bilateral THA, femoral stem type, acetabular shell component diameter, femoral head diameter, and femoral head material type.

Results: Among 671 patients selected from those who used airplanes, 346 patients reported detection by metal detectors. Detection rates for patients with unilateral THA/domestic flights, unilateral THA/international flights, bilateral THA/domestic flights, and bilateral THA/international flights were 23% (81 of 351 patients), 56% (114 of 186 patients), 75% (140 of 204 patients), and 86% (118 of 138 patients), respectively. Logistic regression analysis indicated that the most effective explanatory variables were cup size and material type of femoral head for domestic flights, and cup size for unilateral THA/international flights.

Conclusion: Detection rate was lowest for patients with unilateral THA/domestic flights (23%), and highest for bilateral THA/international flights (86%). Statistical analyses of implant data indicated that cup size was the most significant explanatory variable.