Medical Metrics Inc. (MMI), a leading provider of imaging core lab services for orthopedic clinical trials, has been selected by five leading orthopedic device manufacturers to support multiple cross-sectional, post-market, FDA surveillance studies of metal-on-metal (MoM) hip implants. MMI will independently evaluate radiographs and MRIs to assess long-term outcomes in patients implanted with MoM hips. Over 2,000 subjects will be evaluated at one to ten years post-implantation.
The goal of these studies is to comply with the FDA’s 522 order requiring manufacturers of MoM hip implants to conduct clinical surveillance of the effect of device wear in implanted patients. Rates of reaction to metal wear debris are of particular interest in patients with MoM implants. Reactions are assessed from clinical examination, MRI, and blood tests of metal ion concentration. MMI developed the MR imaging sequences and analysis protocols that will be used for these studies. At this time, two studies have been approved to begin enrollment, and the others are expected to be approved soon.
MMI’s imaging experts integrated current scientific knowledge with prior clinical experience to develop the imaging sequences for assessing the tissues around the implants. Dr. Timothy Mosher, Orthopedic Faculty Director at MMI and Chief of Musculoskeletal Radiology at Penn State College of Medicine, oversaw development of the specialized sequences. Using MRI to assess soft tissue reactions around metal implants can be challenging due to artifact that may obscure the periprosthetic tissues. MMI's technical expertise and knowledge of current advances in clinical MRI played a key role in developing the Metal Artifact Reduction Sequences (MARS) that will be used in these studies.
“Data from carefully-designed imaging studies will advance our knowledge and understanding of the long-term performance of MoM hip implants,” says Dr. Mosher. “Coordinating multiple studies through a single core lab using a standard analysis protocol will provide a unique opportunity for harmonization. By using a common framework to collect and evaluate data on local tissue response, results may be pooled and compared across studies. Ultimately, this level of harmonization will improve our understanding of patient outcomes and provide important data for improving patient management.”