Most hip joint replacements are metal on plastic, but in the past several years, metal-on-metal hips have become popular due to the potential benefits of longer term use. This has been the hope for the new hips, but it has been dashed by concerns about complications from these prostheses. In particular there is premature deterioration of the hip joints, release of metal into the bloodstream, and local inflammation surrounding the hip replacement leading to pain, reduced mobility, and disability.
The FDA has just released recommendations for monitoring that will provide clearer guidance for patients and physicians.
The FDA has released this information here. Review this ‘plain-english’ position statement:
http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm335775.htm