More than a half-million people in the United States each year undergo knee replacement surgeries. Orthopedic surgeons now at have new technology that provides their patients with “custom-fit surgery” for a total knee replacement.
Dr. Frank DiMaio, chief of adult joint reconstruction in the Department of Orthopedic Surgery at LIJ Medical Center, is among the first surgeons on Long Island to introduce the new system (known as patient-specific instrumentation or PSI). Developed by the Warsaw, IN-based Zimmer, Inc., PSI uses magnetic resonance imagining technology that produces precise, three-dimensional images of the knee. Before surgery, physicians use an easy-to-use program on their computer to evaluate computer-generated images of the knee, creating customized surgical guides tailored to each patient’s unique anatomy. A more precise fit is critical given that the environment inside every knee is different.
“The patient-specific instruments or the custom fit surgery is the ultimate road map to total knee replacement surgery,” said Dr. DiMaio. “The technology allows us to make a custom mold, or guide, taking into account the contour and alignments of each person’s knee, giving us the advantage of a virtual computer-guided surgical plan before the patient gets to the operating room.”
Dr. Peter Lementowski, an orthopedic surgeon at LIJ, has also implemented similar custom surgery instrumentation for total knee replacements made by Smith & Nephew, headquartered in London, England. Known as Visionaire Patient Matched instruments, the technology allows surgeons to achieve precise alignment of a patient’s knee implant, potentially reducing wear – a leading cause of early implant failure, said Dr. Lementowski. He also uses the Zimmer PSI technology.
The customized guides are plastic molds which are fixed to the arthritic surfaces of the knee with pins. The individually tailored instruments support optimal preparation of the knee for improved sizing, and placement and alignment of the implant during a total knee replacement surgery. The technology decreases the length of the surgery, added Dr. Lementowski, “resulting in less time a patient needs to be under anesthesia and potentially less blood loss as well as fewer transfusions.”
