Airport detection of modern orthopedic implant metals.

The sensitivity of airport metal detectors to a variety of orthopedic implants shows that total hip and total knee replacements, intramedullary nails, hip compression screws, and bone plates can escape detection. The metallurgic composition of the undetected implants were titanium, titanium-aluminum-vanadium alloy, cobalt-chrome-molybdenum alloy, and some stainless steel. The implants were tested individually, in combination, and as a whole in each of three different metal detectors. Only one of the screened implants activated a metal detector: an old Austin Moore straight fenestrated endoprosthesis that individually activated one of the three metal detectors. All of the other screened implants were not detected by any of the three tested metal detectors. Furthermore, the Moore endoprosthesis failed to activate two of the three tested metal detectors. Metal objects are identified by metal detectors based on their ferrous content. Contemporary orthopedic implants use little, if any, ferrous metal and therefore escape detection by airport metal detectors.