Study: Elevated Cobalt and Chromium Levels Seen Following Metal Disc Arthroplasty

A recent study revealed that patients tested with higher serum cobalt and chromium levels following surgery for all metal total lumbar disc arthroplasty.

The levels, said Helio, were similar to those seen in the same time frame in patients with “well-functioning” metal-on-metal hip implants. “In general, these results indicated that serum Co [cobalt] and Cr [chromium] levels are elevated at all postoperative time points,” Matthew F. Gornet, MD, and colleagues wrote in their study abstract, said Helio.

The prospective, longitudinal study of 24 patients—13 men and 11 women—involved people of an average age of 41 years of age when implanted with a Medtronic Maverick Lumbar Disc at either L4/5 (eight patients) or L5/S1 (16 patients), Helio noted. High-resolution inductively-coupled plasma-mass spectrometry was utilized for the serum assay, which is what revealed increased cobalt and chromium levels postoperatively, according to the study abstract, Helio noted. The study was published in the European Spine Journal, said Health Day News.

Serum metal levels of cobalt and chromium were elevated at all post-operative points up to 36 months following the metal-on-metal lumbar disc replacement, Health Day News said.

Meanwhile, adverse reactions seen in a growing number of metal-on-metal hip arthroplasty system patients recently prompted British researchers to recommend that both imaging results and patient symptoms be reviewed when considering revision surgery to remove these systems. As we’ve written, metal-on-metal hip implants have been linked to high rates of implant failure and early revision.

In March, The Lancet published a study showing that all-metal hip implants fail at a rate of six percent in five years, compared to the two percent seen in plastic or ceramic devices. These findings prompted the authors to call for an end to their use. The U.S. Food & Drug Administration (FDA) also addressed risks associated with metal-on-metal hip implants and asked 21 manufacturers to conduct post-market safety studies on the devices to assess whether they release dangerous amounts of metal ions into the body.

Also, this summer, an FDA advisory panel met to discuss the pros and cons of the devices. At the conclusion of the three-day meeting, the experts advised that metal hip patients undergo yearly physicals, imaging scans, and possible blood screening for metal ions in order to detect complications. Some panelists questioned whether or not metal-on-metal hip replacements should be used at all in the future.

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.

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. Most recently, metal-on-metal total hip arthroplasty (THA) surgeries were associated with the formation of cysts and severe limb swelling, new adverse reactions to the already controversial devices.

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