Published: 12 December 2013

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Blood Testing of Patients with Metal-on-Metal Hip Implants

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Prescriber Update 34(4): 46
December 2013

Medsafe reminds orthopaedic surgeons and GPs of the recommendations regarding blood test monitoring for patients who have received a metal-on-metal hip implant.

The majority of patients who receive a metal-on-metal hip replacement do well with the implant and are thought to be at low risk of developing serious problems. A small number of patients may develop a problem with metal debris deposition that can lead to a progressive soft tissue reaction in proximity to the joint (metallosis).

The metal debris deposition occurs through the build-up of microscopic metal debris through wear at the articular surface of the joint. This issue can be monitored through a heightened level of trace amounts of cobalt and chromium in the blood of a patient. Early revision surgery of poorly performing hip replacements is likely to lead to a better outcome.

The type of monitoring and frequency required is dependent on the nature of the implant used. Further information about monitoring and blood testing of patients with metal-on-metal hips is published on the Medsafe website (www.medsafe.govt.nz/hot/alerts/mom-hip-implants.asp).