Written by Elizabeth Hofheinz, M.P.H., M.Ed. | Tue, Jan 24th, 2012 | Orthopedics This Week
Does your implant have a few too many and go awanderin’? Now there is help. Two hip and knee surgeons from Midwest Orthopaedics at Rush (MOR) are the first in the U.S. to implant all compliant patients with radiostereometric analysis (RSA) beads, something which will reveal if there is any wear or movement in the implant. It also provides the world’s first RSA registry for implants that allows scientists to collect data on materials and designs used for hip and knee replacement prostheses. The procedure was performed at Central DuPage Hospital.
“RSA will let us track relative motion of different implant materials such as metal, plastic and ceramic and provide us data about the safety and efficacy of these devices,” explained Dr. Sporer in the January 18, 2012 news release. “Although research shows that very few hip and knee replacement patients experience failure (less than 10%), now we have data to determine the success of each patient’s implant.”
“This groundbreaking RSA technology allows us to identify problematic implants before they fail and develop an individualized course of action for patients depending on the situation,” says Dr. Paprosky. “For example, if a patient complains of pain, we compare a recent RSA scan to the original scan. If we notice instability, we can intervene, by possibly performing a surgery to stabilize the implant before more complications develop.”
RSA analysis has come to fruition due to the collaboration between the physicians and Halifax Biomedical, a Canadian based biomedical company that developed the stereo radiography technology. Once the beads, or biomarkers, have been inserted into the bone, two or more pairs of stereo x-ray images are taken and sent to Halifax Biomedical. Technicians use visual assessment software to monitor the position of the biomarkers in relation to the implants. If a patient experiences pain, another x-ray of the patient’s joint is taken and compared to the original one to determine the relative motion of implants with respect to the bone. This is followed up with a detailed report showing the stability of the implant.
Dr. Sporer told OTW, “RSA is an extremely accurate technique to assess component stability following total hip and knee replacement. The ability to utilize this technology on all patients, rather than a select subset of patients enrolled in a clinical trial, will allow the early detection of problematic implants and may provide diagnostic information among symptomatic postsurgical patients. It is the hope that the development of the first RSA registry within the U.S. will lead to improved patient outcomes, minimize the need for revision surgery and ultimately reduce the costs associated with arthroplasty surgery.”