September 27, 2012 — The medical device company Smith & Nephew has published a failure warning for the Birmingham hip implant. The “Urgent Field Safety Notice” announces that the average revision rate for the Birmingham Hip Modular Head is higher than the 1% benchmark established by the United Kingdom’s National Institute for Health and Clinical Excellence (NICE).
The metal-on-metal hip implant that has been linked to a 1.29% failure rate based on an analysis of data from the National Joint Registry of England and Wales, and a 1.12% failure rate based on data from the Australian Orthopaedic Association’s National Joint Replacement Registry. The United States lacks a comparable implant database — the U.S. Food and Drug Administration (FDA) only receives voluntarily-submitted injury reports, and does not keep track of the number of implants or the outcome.
The safety notice warns that the device can cause serious health problems, including pain and limited mobility, which may require revision surgery. The risk is highest for females of childbearing age, severely overweight individuals, and other individuals.
Studies indicate that risk factors for failure include patients who receive a smaller component size (46-mm or less), have the device implanted at a high abduction angle, patients who already have osteonecrosis (bone death), or other abnormalities in the hip. There are many other risk factors. Patients with multiple risk factors have the highest risk of failure requiring revision hip surgery.
Smith & Nephew warns that the Birmingham hip implant absolutely should not be implanted in patients with osteoporosis, metabolic disorders, kidney failure, muscle weakness, inadequate bone in the hip area, infection in any part of the body, deficient soft tissue around the hip joint, and patients with metal sensitivity.
Potential adverse events from the Birmingham hip implant include high level of metal debris from the metal-on-metal parts of the implant grinding together. These metal particles can cause severe irritation and inflammation in the hip joint. Smith & Nephew also warns that the products can cause the formation of soft-tissue pseudotumors, lesions, and fluid collections.