Tech Briefs

Wireless Tags Quickly Provide Details About Orthopedic Implants

A non-invasive system employing radio-frequency identification (RFID) technology is designed to give physicians easy access to information about implants and patients.

Radio-frequency technology that uses human tissue instead of air as a conduit for radio waves is the basis of the first electronic “tag” system designed to track and monitor orthopedic implants. A 2009 RAND Corporation (Europe) technical report found that RFID technology offers several advantages to medical care in such areas as wireless data transfer and patient/object identification, and as a sensor.

altThe non-invasive system, known as Ortho-Tag, is an example of the growing potential and role of RFID technology in health care. It features a wireless chip attached to the implant and a handheld receiver that together would let physicians view critical information about artificial knees, hips, and other internal prosthetics — as well as the condition of the surrounding tissue — that currently can be difficult to track down.

The chip, or tag, would have information about the patient, the implant, and the procedure uploaded to it prior to an operation. In addition, sensors within the chip would gauge the pressure on the implant, the chemical balance and temperature of the tissue, and the presence of harmful organisms.

All of this information would subsequently be read by a handheld probe developed in the laboratory of Marlin Mickle, the Nickolas A. DeCecco professor of electrical and computer engineering in Pitt’s Swanson School of Engineering. When placed against the patient’s skin, the probe communicates with a radio-frequency identification (RFID) tag devised in the Mickle lab by Pitt graduate researcher Xiaoyu Liu that emits a unique wavelength designed to travel through human tissue. Special software would display information from the tag on a computer.

The inventor, Lee Berger, recently patented the Ortho-Tag system (U.S. patent 7,932,825), and Ortho-Tag, Inc., has optioned the rights to Mickle’s work. Berger envisions Ortho-Tag being attached to implants by the manufacturer, and he is currently building partnerships with manufacturers. Ortho-Tag, Inc., would distribute the software and probe to physicians. For people with existing orthopedic devices, the company is considering producing wallet- sized cards with an affixed RFID tag uploaded with information about the patient and the implant, Mickle said.

The Ortho-Tag concept was developed to resolve a frequent shortage of information physicians face with patients who receive orthopedic implants. In many cases, patients know little about the type of device they have received, the company that manufactured it, or even the surgeon who had performed the procedure. Those details could only be learned through an extensive paper trail, made even more complex when dealing with out-of-state patients.

Details of the size, model number, and manufacturer of the implant could help physicians provide better follow-up care. Since devices come in different models, shapes, and sizes for use in knees, hips, feet, the spine, and other parts of the body, this technology could be highly useful for doctors, who would simply scan a chip to determine that information.

Another use of this technology is to track down defective implants, which are recalled by serial number; this crucial information is typically kept on written records where the original surgery took place. Ortho-Tag could be used to identify a suspect implant quickly and easily.

This technology was done by Swanson School of Engineering at University of Pittsburgh, Pittsburgh, PA. For more information, visit http://www.engr.pitt.edu.