Monthly Archives: December 2010

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Orthopedic Hardware And TSA Metal Detectors

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Many trauma patients require implantable hardware for treatment of their orthopedic injuries. One of the concerns they frequently raise is whether this will cause a problem at TSA airport screening checkpoints (Transportation Safety Administration). 

The answer is probably “yes.” About half of implants will trigger the metal detectors, and these days that usually means a pat down search. And letters from the doctor don’t help. It turns out that overall, 38% are detected when the scanner is set to low sensitivity and 52% at high sensitivity. 

Here is a more detailed breakdown:

  • Lower extremity hardware is detected 10 times more often than upper extremity or spine implants
  • 90% of total knee and total hip replacements are detected
  • Upper extremity implants such as shoulder, wrist and radial head replacements are rarely detected
  • Plates, screws, IM nails, and wires usually escape detection
  • Cobalt-chromium and titanium implants trigger alarms more often than stainless steel

 If your patient knows that their implant triggers the detectors, they have two options: request a patdown search, or volunteer to go through the full body millimeter wave scanner. This device looks at everything from the skin outwards, and will not “see” the implant and is probably the preferred choice. If they choose to go through the metal detector and trigger it, they are required to have a patdown. Choosing to go through the body scanner after setting off the detector is no longer an allowed option. 

Source: Detection of orthopaedic implants in vivo by enhanced-sensitivity, walk-through metal detectors. J Bone Joint Surg Am. 2007 Apr;89(4):742-6.

General

Removing The Backboard

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Backboard usage by EMS is an important part of patient safety. It keeps the patient from injuring themselves or others within the confines of the ambulance or helicopter. But too much of anything is bad, and this is true of backboards as well. As little as 2 hours on a board can lead to skin breakdown. The most common reason that patients are not taken off boards sooner is concern for spine fractures. But the reality is that the board is not necessary once the patient arrives in the ED. If the spine is broken and they are admitted as an inpatient, they will be on log roll precautions on a regular hospital bed and mattress! I recommend that hospitals develop a policy for getting all patients off backboards as quickly as possible. The most convenient time is during the logroll to examine the back during the ATLS evaluation. Note: do not do a rectal exam during the logroll because this will cause the patient to wiggle more than you would like while they are up on their side. The goal should be to get the backboard removed within 20 minutes of patient arrival. I recommend placing a slider board under them if they will be visiting diagnostic areas like CT scan. But as soon as all studies are finished, pull the slider board as this can cause skin problems as well. Ideally, board removal should be documented, and this whole process can become a PI project.

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Posterior Hip Dislocation

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Although posterior hip dislocation is an uncommon injury, the consequences of delayed recognition or treatment can be dire. The majority are caused by head-on car crashes, and 90% of these are posterior dislocations. The femoral head is forced across the back wall of the acetabulum, either by the knee striking the dash, or by forces moving up the leg when the knee is locked. This occurs most commonly on the right side when the driver is standing on the brake pedal, desperately trying to stop.

On exam, the patient presents with the hip flexed, internally rotated and somewhat adducted. Range of motion is limited, and increasing resistance is felt when you try to move it out of position. An AP pelvic X-ray will show the femoral head out of the socket, but it may take a lateral or Judet view to tell if it is posterior vs anterior.

These injuries need to be reduced as soon as possible to decrease the chance of avascular necrosis of the femoral head. Procedural sedation is required for all reductions, since it makes the patient much more comfortable and reduces muscle tone. The ED cart needs to be able to handle both the patient’s weight and your own. I also recommend a spotter on each side of the cart.

Standing on the cart near the patient’s feet, begin to apply traction to the femur and slowly flex the hip to about 90 degrees. Then gently adduct the thigh to help jump the femoral head over the acetabular rim. You will feel a satisfying clunk as the head drops into place. Straighten the leg and keep it adducted. If you are unsuccessful after two tries, there is probably a bony fragment keeping the head out of the socket

Regardless of success, consult your orthopedic surgeon for further instructions. And be sure to thoroughly evaluate the rest of the patient. It takes a lot of energy to cause this injury, and it is flowing through the rest of the patient, breaking other things as well.

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Drug Use and Automobile Crashes

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All trauma professionals are keenly aware of how often alcohol is involved in automobile crashes. Something you may not know is that one third of drug tests for other substances are positive in drivers involved in car crashes!

There has been a 5 percent increase in the number of positive drug screens in drivers over the past 4 years. The drugs range from hallucinogens to prescription pain medications. 

Seventeen states have enacted legislation making it illegal to drive while on various types of legal and illegal drugs. However, these laws are difficult to enforce because:

  • They are more difficult to detect, both by law enforcement at the scene and in the hospital
  • We don’t know a lot about the impact of these drugs on driving performance
  • A positive drug screen does not tell us when the substance was taken and if it is at a significant level

Drug screens are typically obtained in the ED in seriously injured drivers. It’s a good idea to order one in any patient with a significant head injury. This allows the clinician to guess (and it’s just a guess) that the medications may be impairing the mental status exam. Any patients who have a positive screen should have a documented chemical dependency evaluation and be provided with referral information to get further help.

Reference: National Highway Traffic Safety Administration