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Metal on Metal Hip Devices and the cause for concern

Posted in [Blog Medical Negligence ] on Wednesday, May 11th, 2016

Difficulties with Metal on Metal (MoM) hip devices have been highlighted in the media by the worldwide recall of the DePuy ASR in August 2010 and the discontinuance of the DePuy Pinnacle from mid-2013. MoM hip prostheses were first developed by Peter Ring & Mckee-Farrar in 1961.  The clinical results for these new prostheses were mixed including reports of patients who had undergone revision surgery for unexplained pain and were found to have thick yellow/green hip effusions in association with soft tissue necrosis.  Over time the MoM fell out of common use in favour of MoP (Metal on Polyethylene) prostheses. Despite the reported concerns MoM hip prostheses saw resurgence in popularity with the development of the Birmingham Hip Resurfacing (BHR) in 1997 and the introduction of the DePuy ASR in 2004.  The modern generation of large diameter MoM bearings are manufactured from high carbon cobalt chromium molybdenum alloy.  The implants are either cast or forged and casting may be followed by heat treatments with the bearing surfaces highly polished to optimise wear resistance.  The MoM hip prostheses were a popular choice for younger patients as they were thought to be more durable.In MoM hip implants, the metal ball and the metal cup slide against each other during walking or running.  Metal can also be released from other parts of the implant where two implant components connect.  Metal release will cause some tiny metal particles to wear off of the device into the space around the implant.  Wear and corrosion at the connection between the metal ball and taper of the stem may also occur.  Some of the metal ions (cobalt and chromium) from the metal implant or from the metal particles will enter the bloodstream.The long term health effects of lifelong exposure to increased quantities of chromium and cobalt metal ions in the blood stream are a cause for concern.  There are concerns of disposition of metallic debris in organs and possible carcinogenicity.   Furthermore metallosis has been linked to the formation of non-cancerous tumours, sinew damage, aseptic lymphatic vascular and associated lesions. These conditions are a result of particularly aggressive necrotic erosion of living tissue and cells.  It has also been suggested that cobalt poisoning may result in tinnitus, vertigo, deafness, blindness, optic nerve atrophy, cardiac problems fatigue and cognitive decline.Failure can also lead to severe pain and limping arising from the dislocation/failure of the implant and premature revision surgery is usually required.The safety of medical devices such as hip prostheses is governed in the main by The Liability for Defective Products Act 1991.  This legislation aims to safeguard consumers from products that do not reach a reasonable level of safety and cause foreseeable injury or damage through for example a manufacturing error, design defect or inadequate information on the appropriate use of a product.  The main effect of this legislation is to introduce into Irish law the principle of “strict” liability on the producer, and in certain circumstances, the supplier of a defective product.  Strict liability is the imposition of liability without fault, for damages, on the manufacturer or supplier.   This is different from medical negligence cases (not involving defective products).  There may also be a medical negligence aspect to litigation involving surgically inserted medical devices, such as hip prostheses, if it can be established that the medical practitioner breached the duty of care i.e. the care afforded to the patient was not of the requisite standard and that “but for” the medical negligence/breach of duty of the treating medical practitioner the outcome would have been far different.  Breach of duty may relate to the surgical insertion of the device, the follow up care or indeed the selection of a particular medical device itself over other similar products.Apart from there being a liability on the part of the manufacturer and/or supplier of the product, there may also be a liability for a Medical Practitioner / Hospital or the HSE if they supply defective medical products which are not of “merchantable quality” or “fit for their purpose” under the Sale of Goods and Supply of Services Act 1980.Defective Product litigation throws up a number of practical legal issues:(1) Identifying the correct Defendant(s) for the purposes of legal proceedings.  There are often a number of parties involved in the process: The original manufacturer, The European supplier and/or distributor, The medical facility that purchases and recommends the product to their patients, and The physician who inserts the product. (2) The manufacturers of medical products are often based outside the jurisdiction and even outside of the E.U.  If such is the case the permission of the Court must be obtained to issue legal proceedings against Defendants that are based outside of the E.U.(3) Injuries Board – A defective product action involving personal injury must in the first instance be assessed by the Injuries Board.  However, if there is also a medical negligence aspect to the case the Injuries Board may not assess the claim and instead an Authorisation should be sought from the Injuries Board to proceed with the case through the appropriate Court.(4) Statute of Limitations – The law in relation to time limits when a personal injury is involved is generally two years from the date of wrongdoing i.e. insertion of the defective device.  The Legal Services Services Regulation Act 2015 will extend the period for the bringing of clinical negligence actions to three years.  In some situations the time can be extended for those who did not have knowledge of the wrongdoing (or alternatively that the person did not have knowledge that the wrongdoing caused the injury).In addition, Section 7(2) of the Liability for Defective Products Act 1991, contains what is known as a “long stop gap”, namely that a right of action for a defective product case shall be extinguished upon the expiration of ten years from the date on which the product was put into circulation.  This Section is not conditional on the person being “reasonably aware” of the damage, the defect or the identity of the producer (ie the manufacturer of the product).One should always move expeditiously with defective product/medical negligence case and should contact a Solicitor as soon as possible for advise on the specific time limits applicable to their case.If you are a patient who has been affected by a medical device recall, or if you have concerns about a medical device surgically inserted, contact a member of the Medical Negligence Team at Cantillons Solicitors, 38/39 South Mall, Cork on 021 4275673 or as soon as possible.* In contentious business, a solicitor may not calculate fees or other charges as a percentage or proportion of any award or settlement.   Share on Social

Aisling Maher



Aisling joined Cantillons in 2015 having graduated with an Honours Bachelor in Civil Law (International) Degree from University College Cork. As part of this degree Aisling spent a year studying at Brooklyn Law School in New York where she gained an indelible insight into American legal principles, practice and procedure.

Prior to completing her traineeship with Cantillons, Aisling worked with a private client Immigration Law Firm in New York. Thereafter, she joined a large Corporate Law Firm in Dublin where she gained invaluable experience working in the EU, Competition and Public Procurement Department and the Employment Department working on both contentious and non-contentious matters.

Aisling previously worked in our General Litigation Department and was involved in a wide variety of cases including personal injury claims, road traffic accidents, accidents at work, contract disputes, employment disputes, claims against local authorities and claims against the HSE.

Aisling is currently working in our Medical Negligence Litigation Department and has experience working on various cases involving birth injuries, cancer misdiagnosis, surgical errors and fatal claims.


  • Honours Bachelor of Civil Law (International) Degree
    Completed Law Society Professional Practice Courses at Blackhall Place, Dublin

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