Orthopaedic Implants
(1-5). However, most studies tested a small
Telephone Questionnaire number of patients and implants,
sometimes with inconsistent results.
circle6 Have you had any metal put into you to Several studies were undertaken before
fix a fracture or for any other reason? 2001 and none had focussed upon the
perspective of travelling patients.
circle6 Have you had a joint replacement? In elective orthopaedics, knee
replacements have overtaken hip
circle6 Have you ever set off a metal detector replacements to become the most
due to metal in your body? commonly implanted of prostheses. Last
year alone over half a million people
circle6 Have you ever been asked at the underwent knee arthroplasty in the UK and Figure 2b. Adams AD-16
airport if you have any metalwork in USA combined. (6,7). hand-held metal detector
your body? We decided to survey a cohort of patients
with knee replacements to learn about telephone calls were performed by two
circle6 Has it ever worried you that the metal their recent experiences at airport security. junior doctors between October 2006 and
may set off a metal detector at a In addition, with the collaboration of the December 2006.
security point e.g. an airport? British Airports Authority (BAA), we tested
‘live’ WTMDs at a major UK airport using a Detection Devices and
circle6 If so, where was it and what variety of implants used in trauma and Procedures.
happened? orthopaedic surgery. We wished to learn The second part of the study was
about procedures employed by the BAA conducted at Stansted International
circle6 Have you ever found it necessary to when confronted by passengers triggering Airport, UK in January 2007. A selection
tell the security that you have metal in security scanners. of common orthopaedic implants of
your body? standard size were taken through two
Material and Methods WTMDs manufactured by OSI Systems
circle6 Did a surgeon ever tell you that there Our study was conducted in two parts. In (Fig 2a), set at different activation
could be a risk of this happening? the first part, patients who had undergone thresholds. The implants were then
knee arthroplasty took part in a telephone screened using a hand-held detectors
circle6 Would you find it helpful to have questionnaire (Fig 1.). manufactured by Adams Electronics
written documentation of your surgery Patients were identified from the senior (see Fig 2b). The sensitivity settings
to show to security? author’s logbook of operative procedures used were those currently deployed at
and were taken from both the public and Stansted. Passage through the WTMDs
Figure 1. The telephone questionnaire private sectors. All patients had been and screening with the hand-held
administered to all of the patients operated upon, by the senior author, detectors was supervised by BAA
between January 2004 and July 2006. The security officers.
around the world. In line with the Implants were individually wrapped in
International Air Transport Association polyethylene bags and carried through by
(IATA) desires, we propose the the senior author, who was free of other
development of a more harmonised metallic objects and had passed
approach to screen international travellers. undetected by the scanners prior to
testing. If the implant activated either of
The Challenge the WTMD scanners while being carried
Since the aircraft hijackings of 11th through it was then wrapped in a cotton
September 2001, airport security has been sheet (representing clothing) and then the
tightened around the world. A passenger by test was repeated.
passenger physical pat-down examination
is possible but it is slow and uneconomic Implants
given the ever-rising number of air The implants tested were those commonly
travellers. Instead, most international used in orthopaedics. (Table 1 overleaf)
airports screen individuals using WTMDs
designed to detect metal. Patient Testing
Many patients with fractures and arthritis Two patients, one with a cemented total
receive metallic internal fixation devices and knee replacement (Genesis 2, Smith and
prostheses. Since 2001 we, at Cambridge Nephew, U.K) and another with bilateral
University hospital, Addenbrooke’s site, have (both left and right) unicompartmental
been approached by several patients knee replacements (Oxford, Biomet, U.K.)
concerned that their orthopaedic implant walked through both WTMDs and were also
will set off alarms at airports. Figure 2a. Rapiscan’s Metor 160 walk tested with the hand-held scanner. Neither
Several studies have investigated the through metal detector, of the type used at patient had any other metal implants and
ability of scanners to detect metal implants London Stansted both were free of other metal objects.
Aviationsecurityinternational December 2007 www.asi-mag.com 25
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