Short answer: it depends on the implant's size and material — and it matters less than it used to. Most modern implants are titanium or surgical stainless steel, both weak targets for a metal detector. Small hardware (screws, plates, dental implants) rarely alarms. Large joint replacements sometimes do. And at most major airports, walk-through metal detectors have been replaced by millimeter-wave body scanners that work completely differently.
Which Implants Trigger Alarms — and Which Don't
| Implant | Typical material | Likely to alarm a walk-through detector? |
|---|---|---|
| Dental implants, fillings | Titanium, ceramic | Almost never |
| Bone screws, small plates | Titanium | Rarely |
| Spinal rods | Titanium/stainless | Occasionally |
| Hip replacement | Titanium/cobalt-chrome | Sometimes — larger mass |
| Knee replacement | Cobalt-chromium alloy | Most likely of the common implants |
| Pacemaker/ICD | Titanium case | Rarely alarms — but see the safety note below |
Two factors decide it: metal mass (a knee replacement is a lot of alloy) and material (cobalt-chromium is more detectable than titanium). Sensitivity settings vary by venue, which is why the same knee alarms at one courthouse and not another.
Body Scanners Changed the Game
Millimeter-wave scanners — now standard at most US airports — image the surface of the body rather than detecting metal. Implants under the skin don't alarm, though the scanner may still mark the area for a brief pat-down. If you have a large implant, you can tell the officer before screening; a doctor's card is optional and doesn't exempt you from screening, but it can make the conversation faster.
A Note on Pacemakers
The old advice to avoid metal detectors with a pacemaker is largely outdated — modern devices are well shielded, and walking through a security detector at a normal pace is considered safe by device manufacturers. The sensible practice is simply not to linger inside the archway, and to mention the device to security staff. Follow the specific guidance from your device manufacturer and cardiologist.
What About Handheld Wands?
Security wands held directly over an implant site will often detect larger hardware — that's exactly what they're for, resolving walk-through alarms precisely. Screeners are trained to expect implant hits, so a positive at your hip or knee with a matching explanation is routine.
Hobby Detectors Will Find Implant-Grade Metal
If you drop a titanium bone screw on the lawn, a ground-search detector will find it — hobby machines from our metal detectors collection run at far higher sensitivity than checkpoint equipment. It's a good reminder that "didn't alarm at the airport" never means "invisible to detectors."
FAQ
Will my hip replacement set off airport security?
Sometimes. Titanium hips often pass older walk-through detectors; larger or cobalt-chrome components alarm more often. Body scanners won't alarm but may flag the area for a pat-down.
Do knee replacements set off metal detectors?
Knee replacements are the most likely common implant to alarm, due to their cobalt-chromium mass.
Do dental implants set off metal detectors?
Practically never — they're tiny and usually titanium.
Is it safe to walk through a metal detector with a pacemaker?
Modern pacemakers are shielded and walking through at a normal pace is considered safe — don't lean on or linger inside the archway, and follow your device manufacturer's guidance.
The Bottom Line
Small implants pass unnoticed; big joint replacements sometimes beep; body scanners mostly sidestep the question. Either way, screening is routine for staff — a quick heads-up is all it takes. Curious how detection actually works? See our guide to what metal detectors detect.
