Published: June 2012

Metal-on-Metal Replacement Hip Implants

Information on this subject has been updated. Read the most recent information.

Prescriber Update 33(2): 19-20
June 2012

Medsafe and the New Zealand Orthopaedic Association support recent advice issued by the UK Medicines and Healthcare products Regulatory Agency on the management of patients who received metal-on-metal hip replacements.


In August 2010, DePuy Orthopaedics issued a hazard alert to New Zealand surgeons that data from the UK National Joint Registry showed revision rates of 13% for ASR hip replacements1.

As DePuy had ceased supplying these hip replacements in New Zealand in December 2009, there was no need to recall un-implanted hip replacements. However, in the rest of the world, un-implanted ASR hip replacements were recalled.

The alert advised surgeons to contact their patients and recommended monitoring and follow-up of those with the ASR hip replacement1. Medsafe understands a total of 525 devices have been implanted in 400 New Zealand patients.

DePuy did not recommend the prophylactic revision of ASR replacement hips in asymptomatic patients. This is consistent with expert advice issued both in New Zealand by the New Zealand Orthopaedic Association and internationally.


In April 2012, Stryker issued a hazard alert regarding its MITCH TRH modular head and cup when used in conjunction with un-cemented Stryker Accolade femoral stems2. The UK National Joint Registry showed this combination had significantly higher revision rates than other total hip prostheses.

The issue with the MITCH TRH related primarily to loosening of the femoral stem and is not related to the issue experienced with the DePuy ASR.

The alert recommended surgeons follow up with patients and advise them of this issue2. Although 106 MITCH modular heads and cups have been implanted, Medsafe understands only 41 were used in combination with the Stryker Accolade femoral stem.

Stryker ceased supply of MITCH TRH modular heads and cups in New Zealand in August 2011.


The majority of patients who receive a metal-onmetal hip replacement do well with the implant and are thought to be at low risk of developing serious problems.

In a small number of patients a soft tissue reaction may occur due to a build-up of microscopic metal debris through wear at the articular surface of the joint. Surgeons have been informed that this issue can be monitored by measuring trace amounts of cobalt and chromium in affected patients.

Further information and recommendations for management of patients with metal-on-metal replacement hip implants is published on the Medsafe website

  1. DePuy Orthopaedics. 2010. DePuy ASR™ Articular Surface Replacement and ASR™ XL Acetabular System. Hazard Alert 26 August 2010. URL: (Adobe PDF document 127KB) (accessed 24 May 2012).
  2. Stryker Australia & New Zealand. 2012. MITCH TRH modular heads. Hazard Alert 12 April 2012. URL: (Adobe PDF document 12 KB) (accessed 24 May 2012).