Consumers continue to be concerned that hip replacement devices wear down, releasing metal particles that react with the body’s tissues and enter the bloodstream, leading to significant adverse physical reactions.
Metal-on-metal hip devices made headlines in August 2010 when DePuy recalled 93,000 of its devices worldwide over high failure rates. Studies have since revealed that the failure rates seen with the DePuy device were neither brand nor manufacturer specific and were, rather, unique to the entire class of device. Researchers now believe that metal-on-metal implants shed ions when the implants’ surfaces articulate, or rub against each other, which may lead to a number of adverse reactions.
We’ve long written that research has linked metal-on-metal hip implant devices to a growing array of adverse events that include tissue necrosis, pain at the implant site that sometimes spreads to the groin and back, inflammation, swelling, metal poisoning, high failure rates, osteolysis (bone loss), and fluid collection/solid masses around the hip joint.
Since, noted the Tyrone Times, the health regulator there, the Medicines and Healthcare products Regulatory Agency (MHRA), has urged surgeons to advise patients who have been implanted with the defective DePuy ASR hip devices about the recall, and to schedule those patients for yearly follow-up visits, said the Tyrone Times. For patients who complain of pain, surgeons in the UK were advised to consider measuring metal levels in patients’ blood and to examine patients’ tissue to determine of reactions have occurred. In the most serious cases, removal and replacement of the devices—revision surgery—should be considered.
According to the Tyrone Times, the Sunday Telegraph is discussing the issue of metal-on-metal hip replacement devices, again, over what it described as “subsequent developments,” saying that the devices’ risks are even greater than first believed and pose even greater rates of failure. In fact, said the Telegraph, the MHRA is creating a new alert for metal-on-metal hip replacement patients.
In total hip replacement, an artificial ball is attached to the top of the leg bone and an artificial socket is attached to the hip bone. When the surfaces of these devices are constructed of metal, which is made with chromium and cobalt, the metal pieces can rub against each other, shedding particles, the Tyrone Times explained. Other problems involve joint loosening, hip fracture, adverse reactions in the soft tissue around the hip, pain, swelling, loss of movement, and limping.
Most recently, we wrote that metal-on-metal hip arthroplasty (THA) surgeries have been associated with the formation of cysts and severe limb swelling, new adverse reactions to the already controversial devices. These cysts can present as either pain or a groin mass. Also, vein compression and limb swelling have been seen in metal-on-polyethylene THA devices related to these types of bursal lesions, as well as a result of pseudotumors with metal-on-metal resurfacing devices. Cyst treatment typically requires removal of the metal debris source, in these cases, the metal-on-metal hip device. Generally, this is accomplished by revision surgery to a nonmetal-on-metal bearing interface as well as drainage of the cyst and removal of damaged tissue and foreign objects (debridement).