There was a two-hour scientific session at the recent annual meeting of the American Academy of Orthopedic Surgeons in San Diego, California in February 2011.
While most patients with metal-on-metal total hips enjoy good function and resolution of pain, there is a small number of patients who experience either persistent pain or the appearance of pain after one year. There appear to be several interacting factors that influence the appearance of pain. These include implant design, surgical technique, and patient-specific factors. The problem has a name which continues to evolve, and most recently has been termed “adverse tissue reaction” which can range anywhere from some fluid or swelling in the tissue around the hip joint to the formation of cysts or masses. The incidence seems to be higher in one-piece metal cups and surface replacements and lower in modular or two-piece acetabular components.
There is extensive work currently ongoing to further evaluate the causes of this condition. If you have a metal-on-metal total hip and have persistent pain or the onset of new pain, you should contact your orthopedic surgeon. A workup for painful total hip will ensue, which will include a history, physical exam, x-rays, and possibly laboratory testing, and if indicated, advanced imaging techniques such as an MRI.
If you have questions, you should contact your orthopedic surgeon.
William P. Barrett, MD