Smith & Nephew, a medical device manufacturer based in the United Kingdom, announced on November 15th, that it would be recalling all of its modular neck hip prostheses due to reports of adverse events. The company issued the recall for all lots of this component, which is used in its Modular REDAPT and Modular SMF Revision Femoral Hip Systems. The recall has been voluntarily issued by the company.
Adverse Events for the Modular Neck Hip Prosthesis
The Modular REDAPT and SMF hip systems were introduced on the marketplace by Smith & Nephew in 2012 and 2008. All of the implant systems that were shipped out from the company between October of 2016 and the present are affected by the recall. The company announced that the reason for the recall was a higher than expected number of adverse event reports.
The adverse events reported to be associated with the Smith & Nephew hip implants were mostly related to high levels of metal in the joint area and in the blood of patients, and with the need for revision surgeries. The metal components of the hip system, rubbing together, may cause metal fragments to flake off from the hip and irritate the surrounding tissue. This can cause pain, swelling, high levels of metal in the blood, and serious damage to tissue and bone.
Patients Must Be Monitored
Smith & Nephew included in its recall, information for doctors of patients who have already received the REDAPT or SMF hips. These patients are at risk for developing the symptoms of a hip failure and are to be monitored for pain, swelling, limited mobility, and other signs that a revision may be needed. The company also recommends that patients be tested for levels of cobalt and chromium in the blood. Too much of these metals from the hips can cause harmful reactions in soft tissues called metallosis. Patients may also need to undergo imaging scans to evaluate the health of the joint and the status of the implant.
Metal-on-Metal Hip Implants
Smith & Nephew is not the only artificial joint manufacturer to face this problem. In recent years many companies have designed and built artificial hip systems made of metal components. These were supposed to give patients more durable hips that would last longer and stand up to greater levels of activity. Unfortunately, there have been unforeseen issues with this design.
Much of the problem comes from the fact that when the joint moves, one metal component rubs against another, which causes small fragments of metal to wear away and enter surrounding tissue or blood. Not everyone reacts badly to the metal, but some patients experience painful symptoms, including what is called an adverse local tissue reaction. This refers to damage to the bone and soft tissue surrounding the joint and can in turn lead to a loosening of the joint, pain, and ultimately the need for revision surgery.
According to Smith & Nephew, its recently recalled hip systems were associated with 0.527% and 0.25% adverse events out of the total number of patients receiving them. This may not sound like a lot, but the rates are higher than with comparable hip systems, and for those patients having a bad reaction to the hip systems, the pain, discomfort, and need for additional surgery is disruptive and damaging. There have been no overall recalls of metal-on-metal hip systems, but many patients who have suffered because of them have filed lawsuits against the manufacturers.