Detection of orthopaedic implants by airport metal detectors

To report the effect of patient's body mass index (BMI), implant type, size, location, number, and material on detection by certified Transportation Security Administration (TSA) and Federal Aviation Administration (FAA) airport metal detectors set to today's standard sensitivity.

Retrospective clinical study.

Level 1 university trauma center.

Ninety-six regularly scheduled trauma clinic patients with a wide variety of orthopaedic implants were enrolled in the study from August 2004 through December 2004.

Patients walked through an airport arch metal detector and were also wanded with a handheld metal detector.

Detection of implants by arch detector or wand was recorded. We also gathered information regarding BMI, location of implants, type, metal composition, and size.

All unilateral prostheses (8/8) and bilateral prostheses (1/1) were detected. Subjects with 4 or fewer screws and no other implants were never detected by the arch metal detector (0/7). For the remaining 78 subjects, the 2 best predictors of detection by the arch were having plates of length >10 holes and having titanium nails (P < 0.001 for each predictor, Wald's test for effects in a logistic model).

Prostheses, plates of length >10 holes, and titanium nails were the best predictors of detection by the arch. These 3 factors accounted for 42 of the 43 detections by the arch. Body mass index was not shown to affect detectability of orthopaedic implants.