Orthopaedic Implants
Table 1. Size, detectability and composition of orthopaedic implants tested
Implant Composition Weight Less sensitive Less sensitive Hand held
(g) scanner (wrapped) scanner (wrapped) scanner
Bipolar hip arthroplasty Cobalt chrome head & 325 +(+) +(+) +
stainless steel stem
Thomsons hip arthroplasty Vitallium 342 5 bars* 5 bars* +
Austin Moore hip arthroplasty Vitallium 418 +(+) +(+) +
TKR femoral component Cobalt Chrome 257 5 bars* (3) +(4) +
TKR tibial component Titanium 64 1 bar* 1 bar* +
TKR both components 321 5 bars* +(+) +
TKR Oxinium femoral component Oxidised Zirconium 291 +(+) +(+) +
Unicompartmental femoral component Cobalt chrome 35 - - +
Unicompartment tibial componant Cobalt chrome 29 - - +
Unicompartment both components 64 2 bars* 2 bars* +
RCI screw Titanium 4 - - +
LISS (13 hole) (a type of long trauma plate) Titanium 116 2 bars* 2 bars* +
Femoral nail Stainless steel 136 2 bars* 2 bars* +
Dynamic hip screw Stainless steel 132 2 bars* 2 bars* +
Long stemmed revision TKT Cobalt chrome 69 +(+) +(+) +
*Bars – WTMD have a series of lights (“bars”) to indicate the detection of metal. Up to and including five bars indicates a disturbance of the
electromagnetic field below the threshold for activating the alarm.
Figures in parentheses refer to the detection after the implant was wrapped in the cotton sheet
Patient Survey Results circle6 102 (68%) patients said that they had Implant Detection
circle6 155 patients were surveyed (63 male, felt anxious about the possibility of The results of implant detection are listed
92 female). The average age was 71 setting off the airport scanners. Of the in Table 1.
years (range 42-90 years.) patients who had activated the scanner,
circle6 Of these, 111 patients had undergone a two patients reported difficulties at Patient Detection
single total knee replacement (TKR) security checkpoints at foreign airports. The patients with a TKR activated the
whilst 17 had undergone bilateral TKR. One patient was asked to show alarm on both WTMDs. In contrast, the
Another 22 patients had undergone a documented proof of surgery at a patients with bilateral UKR did not activate
unicompartmental knee replacement German airport, another had difficulty either alarm.
(UKR), of which two had undergone explaining the surgical procedure and a
bilateral UKR. This totalled 150. third was asked to demonstrate their Discussion
circle6 Five patients had to be excluded from surgical scar and was detained. An estimated 750 million international
analysis, all of whom had undergone a circle6 Five patients routinely asked for a passengers were enplaned in 2006. To
single TKR, as one of the 155 patients doctor’s letter prior to travelling. efficiently screen the ever-rising tide of
also had a shoulder hemiarthroplasty for circle6 One patient volunteered the information air passengers, airports routinely use
trauma, two also had total hip that he had activated a metal detector at WTMDs. (8)
replacements and two patients had died a bank and another patient said that she In the U.K. over 60,000 patients under-
since their knee replacements. routinely activated a metal detector in a went total knee replacement in 2006 (7).
circle6 Of the 150 qualifying patients, 69 had high street shop. Within the last few years, some of our
travelled through an airport at least circle6 None of the patients surveyed had been patients with knee replacements reported
once since surgery. Of these patients, warned about the possibility of activating a activating metal detectors at airports. Many
47 patients had a TKR, 45 (96%) of metal detector by an orthopaedic surgeon. others were concerned about that possibility
whom activated detectors. 33 (73 %) circle6 When asked if they would have liked to and its associated embarrassment, delay
of those activating a detector always have received written proof, verifying the and detainment.
activated it and 12 (27%) patients presence of an implant, 127 (84%) In 1992 Pearson et al. and subsequently,
intermittently activated the detector. thought this would be a good idea. in 1997, Grohs et al. concluded that knee
Two patients had never activated a
detector. Table 2. Responses from the questionnaire for patients with knee replacements.
circle6 11 out of 17 patients with bilateral TKR
had flown. All these patients had Prosthesis Number activating Number not activating Total travelling
activated metal detectors.
the detector the detector through airports
circle6 10 of the 20 patients with UKR had
TKR 45 2 47
flown, none of whom had set off alarms.
Bilateral TKR 11 0 11
One of the two patients with bilateral
UKR 0 10 10
UKR had travelled without triggering the
Bilateral UKR 0 1 1
detector (see Table 2).
Total 56 13 69
26 December 2007 Aviationsecurityinternational
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