|
- - - - - - - - - - - - - - - - - - - - - - - - -
General Joint Surgery Information
Detection of Orthopaedic Implants by
Airport Mental Detectors
Roger Emerson, Jr., MD
Recently, there have been a number of orthopaedic studies
conducted on the detection of orthopaedic implants by airport
metal detectors.
Patients with implanted joint prostheses often ask whether
the implants will produce problems with security checks at airports.
Each year at airports around the world, thousands of passengers
have re-examinations by handheld detectors and body checks because
of positive results at detection arches.
Body checks of patients with orthopaedic implants are often
necessary because electronic devices cannot distinguish between
these and other metallic sources. The goal of the studies was
to determine which implants, if any, activate metal detectors
so that patients with such implants can be forewarned and a
certificate issued.
Metal detectors create an electromagnetic field. When an active
metallic object is moved across the field, an induction current
is generated which is registered by the detector. This process
is usually not affected by the presence or absence of a cover
of body tissues.
The sensitivity of the detector varies and is represented
on a scale of 1 to 15; an average airport detector is set at
five. In those parts of the world where security is considered
to be at a higher risk the detector is set at seven. At a setting
of 10, the detectors are activated by minute metal objects such
as rings and coins and are of little use for airport security.
Therefore, tests were done at settings of both five and seven.
Most implants are made of lightweight stainless steel, titanium
or a cobalt-chromium-molybdenum alloy and thus are non-magnetic
so one would think they would be less likely to set off a metal
detector. So, what were the results of the study?
The findings were that patients with a single joint replacement
were unlikely to activate a metal detector at its normal setting
of five, however, their implant may be detected at a setting
of seven. Patients with two implants are also unlikely to set
off a metal detector at its normal setting, but are more likely
to be stopped at a setting of seven. Patients with three or
four standard hip and knee replacements will usually activate
an alarm.
The conclusion of these studies is that while it is unlikely
that a single joint implant will set off an alarm at an airport,
it is probably a good idea for all joint replacement patients
to carry a card with them that indicates that they have a metal
implant. With airport security becoming more and more of an
important issue in airports around the world, it’s better to
be safe than sorry.
If you do not have an implant card, please contact your surgeon's
office to obtain one.
|
