Metal on metal hip implants are commonly used during hip replacement surgery. Patients with damaged hip joints have different, individual needs that depend largely on the amount of damage to their joint(s), as well as their overall health and daily activity levels.
Some patients require a partial hip implant, while others require a completely new hip joint. Patients may need a hip implant for one or both hips. Replacement hip implants are made from plastic, ceramic or metal materials. However, not all implants are safe, and some can cause serious complications.
Many patients who have been harmed by a metal on metal hip implants have filed lawsuits against the medical device companies that produce and sell the implants, as they feel the companies should be responsible for covering the costs associated with a patient’s revision surgery, lost wages, or lost quality of life.
Hip replacement surgery, also called hip arthroplasty, is intended to aid in patient mobility by replacing a diseased or injured natural hip joint with an artificial joint, or implant. Many patients undergo this type of surgery due to a cracked or fractured hip joint, or because their hip joint has worn out due to constant use over a long period of time.
However, a type of debilitating arthritis known as osteoarthritis is the most common culprit behind hip replacement surgeries. Patients between the ages of 50 and 80 are most likely to require this surgery due to osteoarthritis. In 2015, U.S. surgeons performed nearly 378,000 hip replacements surgeries, the majority of which were required due to osteoarthritic damage to patients’ hip joints.
The intended goal of hip replacement surgery is to reduce pain and provide a patient with increase mobility and therefore, an increased quality of life. For this reason, hip implants are designed to move fluidly to replicate the natural movement of the hip as closely as possible.
From 2013 to 2014, the FDA received over 20 reports of ketoacidosis in patients treated with Invokana or similar medications. All of the patients were affected severely enough to require hospitalization. Currently, the FDA is still receiving reports of ketoacidosis in relation to Invokana, despite having ordered Johnson & Johnson to add a warning to the drugs’ label in 2015.
Most hip implants are made from a combination of materials, including plastics, ceramics and metals. However, many of the most recent devices were designed entirely out of metal, with the hopes of providing years of pain-free mobility to younger, active implant recipients. Yet, recent studies have concluded that metal on metal hip implants can cause an array of complications and side effects, including:
Blood clots. After undergoing metal on metal hip implant surgery, patients have an elevated risk of developing blood clots in their legs. If left untreated, these clots can travel to a patient’s lungs, heart or brain and cause strokes, heart attacks, or even death. Doctors oftentimes prescribe blood thinners to hip implant patients to reduce the risk of blood clot formation, but blood thinners such as Xarelto may cause uncontrollable internal bleeding.
Infections. Infections are a common occurrence with metal hip implants and often affect any tissue that comes in contact with the device. If caught early, infections may respond well to antibiotic treatment, but deep infections may require additional surgery to remove the implant.
Dislocation. This complication is most likely to occur within the first few months of having metal on metal hip implant surgery. Dislocation happens when the implant’s ball pops out of the hip socket. The joint can sometimes be put back in place, either with or without surgery, but the chances a dislocation will happen again are quite high with this type of hip implant.
Uneven leg lengths. After hip replacement surgery with a metal on metal hip implant, patients are prone to having one leg that is noticeably shorter or longer than the other one. Uneven leg length can result in instability while walking or standing, as well as loss of coordination and balance.
Fracture. If a patient’s pelvic or leg bones are weakened or brittle, they can fracture after being connected via a metal on metal hip implant. Due to the durable nature of these implants, they are often too powerful or too strong for some recipients, and can result in the splitting or cracking of their pelvic or leg bone. Additional surgeries may be required to replace the metal implant with one constructed from a different material.
Metallosis. Rarely seen in individuals without metal implants, this condition is caused by the buildup of metallic debris in the soft tissues of a patient’s body. Debris from metal-on-metal hip implants can flake off during movement and become imbedded in nearby soft tissue. When this occurs, the toxic debris starves tissue cells of much-needed oxygen and can lead to tissue death. The metal debris can also cause other severe side effects, including:
Following an influx of hip replacement surgeries in which metal on metal implants were used, hundreds of patients were forced to undergo additional surgeries to correct a wide array of complications and side effects. Often, these corrective surgeries were performed less than two years after the patients’ original operation.
Revision surgery is performed to replace one or more artificial hip components that have loosened, worn out, become dislocated or caused other serious complications. These procedures are tougher for surgeons and patients alike, since typically more bone must be removed and new implant parts inserted. The mortality rate also rises: For original hip replacement procedures, the death rate is 1 percent; for revision surgeries, the rate is 2.5 percent.
Please visit www.orthoinfo.aaos.org or www.fda.gov to learn more about this topic.