Sunday, 1 April 2012

Metal on Metal Hip Implants – An Experiment


Article by
Kevin Timms

In a recent article by the BMJ, following an investigation by the BMJ and BBC Newsnight, it has been found that hundreds of thousands of individuals around the world have effectively been participating in an uncontrolled experiment.

Unlike the PIP breast implant scandal, these issues do not revolve around on manufacturer but rather this is a whole class of hip implants failing. The issue with metal on metal (or MoM) hip implants is that the ball and cup of the hip implant is made from a cobalt-chromium alloy rather than the more traditional ceramic or plastic hip implants.

One of the more controversial aspects of the metal on metal hip implants is that they were acclaimed to be the most advanced hip implants on the market when they were introduced in the late 1990s. It was also stated that they have a much longer shelf life and were routinely marketed to younger patients. However, it is now evident that metal on metal hip implants fail at a much higher rate than other hip implants on the market. Metal on metal hip implants have been used in over 60,000 patients in England and Wales since 2003.

The BMJ article confirms that cobalt-chromium implants have been used successfully in orthopaedic surgery for years. Whilst is has been known that cobalt-chromium implants release metal ions, some metal on metal implants release ions on a much greater scale than previously thought. These ions cam enter surrounding tissue causing the destructions of the tissue and bone. This can leave individuals with a long term disability.  The BMJ reported that the cobalt-chromium metal ions leach into the blood stream spreading to the lymph nodes, spleen, liver and kidneys prior to being excreted in urine.

Metal Ions, Genotoxicity and Uncertain Risks

There have been a number of studies which have warned about the carcinogenic potential of metal on metal hip implants. At present the link to cancer is not proven.

The toxicology of metal ions in the body is uncertain. In 2007, the Lancet said “Little is known about the transport, distribution and excretion of metal ions in the body … toxic effect thresholds have not been characterised”. Professor Freemantle at the University College London, suggests this level of uncertainty would not be acceptable in drug relation. He said “if it was the pharmaceutical industry developing a new chemical entity, it would be abandoned early on if it metabolised in the wrong bits of the liver … we shouldn’t be in this position where we don’t know and there’s so much uncertainty. The stability of a compound should have been ascertained before it was used widely in people. As yet, we don’t know the consequences of this.”

At present there are no guidelines on what constitutes an unacceptably high level of cobalt ions in the blood for patients receiving any orthopaedic implant, let along a metal on metal hip implant. Some studies have shown that the blood cobalt concentrations generated through the wear of some of the newer metal on metal hip implants can be 600 times higher than the physiological levels of cobalt that most healthy people have.

A problematic issue is with smaller hip resurfacing implants which lubricate less well. These are often used in women and smaller men and produce metal debris and high concentrations of metal ions in the blood.

It is unquestionable that the problem with metal on metal hip implants is particularly bad as a result of numerous regulatory failures.

If you have received a metal on metal (MoM) hip implant and you are experiencing adverse symptoms, contact Kevin Timms for free advice on how Garden House Solicitors can help you bring a metal on metal hip implant compensation claims. Kevin can be contacted on 01992 422 128 or email Kevin at Kevin@gardenhousesolicitors.co.uk.


Tel: 01992 422 128

The contents of this article are intended for general information purposes only and shall not be deemed to be, or constitute legal advice. We cannot accept responsibility for any loss as a result of acts or omissions taken in respect of this article.

No comments:

Post a comment