If you’ve recently been through security at an airport, you were probably reminded of how many people are living with metal implants.

While many permanent metal implants are the result of joint replacement surgeries, medical hardware such as plates, screws, rods and pins are also used to help heal broken bones.

The purpose of these devices is to bring stability to the area and to aid in the healing process.

Originally, external fixation devices such as casts and splints were the best that medicine could offer for broken bones. However, technological advances now allow doctors to use internal fixation devices at the actual injury site.

Orthopedic surgeons are specially trained to recognize when these devices are needed, and which type of device should be used.

“Plates are mainly used to keep alignment, especially near joints,” explains Dr. Bharat Desai with Panorama Orthopedics & Spine Center in metro Denver. “If you have a fracture near the joint, you can’t put a rod down.”

Dr. Desai said that understanding the biological impact of internal fixation devices is important to being able to use them correctly.

A bone with a good blood supply is able to heal itself, but the way that it heals is determined by how much movement is taking place, or how much strain there is on the break. For some injuries, a certain amount of strain is actually good because healing to solid bone may not be the desired result.

“What the body looks at is how much motion is there,” Dr. Desai explains. “What plates and screws do, is the surgeon is convincing the bone to heal straight to bone, do callus, or form fibrous tissue. The surgical procedure is convincing it to do it one way.”

As Dr. Desai describes it, it is science working together with biology.