SAN FRANCISCO, March 10, 2004 -- Anyone who has boarded an airplane since September 11, 2001, has observed security personnel asking passengers to slip off shoes and remove watches. And few travelers have escaped the drone of a metal detector after it senses a foreign object in someone's pocket.

Now researchers in the United Kingdom have studied the experiences of travelers with orthopaedic implants and reported the results today at the 71st Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) in San Francisco, March 10-14, 2004.

Researchers found that detection of implants has risen from an average of 10 percent before Sept. 11 to more than 50 percent after. Yet, detection rates were variable and seemed based, at least in part, on the type of material used in the implant. About 70 percent of device wearers surveyed had not been informed that their implants could set off security devices at all.

P. Yates, FRCS, and a team of researchers from the Royal Bournemouth Hospital, department of orthopaedic surgery, surveyed more than 100 patients with orthopaedic implants and analyzed almost 300 flight events between 1996 and 2004 to find out if implants had been detected by security equipment in airports. Most of the travel occurred within Europe, with patients listing their experiences with 75 European airports. The other 24 airports were in Australia, Asia, and North and South America.

Certain devices almost guaranteed that a traveler would get pulled out of line for a thorough search, while others sometimes slipped past the radar. For example, patients with replacement hips containing cobalt chrome always set off the detector after September 2001. However, rates of detection were inconsistent across other types of implants and varied over time and place. Sometimes travelers' implants were detected, sometimes not -- which may come as a surprise to travelers and those concerned with airport security.

The general public has been told that metal-detector settings are much more sensitive than before September 11, and airport security personnel contacted by the researchers said they thought machine settings were now sensitive enough to pick up all joint replacements.

Excessive security delays encountered by travelers with implants seemed to be exacerbated by language barriers. To alleviate joint replacement patients' travel impediments, the research team suggests introducing an internationally recognized joint replacement card linked to a joint registry database. This would also adhere to the U.S. Enhanced Border Security & Visa Entry Reform Act of 2002 and conform with the U.S. Immigration & Naturalization Service's requirement that all commercial airlines submit detailed passenger manifests before arriving or departing the United States.

The AAOS has suggested that physicians routinely offer patients a letter or card as proof of implant surgery as a way of dealing with airport security checks for patients with medical implants. Be advised, however, that a note from a physician will not necessarily speed up the move through security. If a security alarm sounds, the Federal Aviation Administration requires a resolution: A hand-held screener is used, and, if needed, the implant patient must consent to a noninvasive body search in order to board the plane. Co-authors of the study were S. Serjeant, MCSP; C. Plakogiannis, MBBS; and R. Middleton, FRCS.

An orthopaedic surgeon is a physician with extensive training in the diagnosis and non-surgical as well as surgical treatment of the musculoskeletal system, including bones, joints, ligaments, tendons, muscles and nerves.