Follow the leader: metal-on-metal hip implants

We read with interest your news article on the recommendation from the Medicines and Healthcare Products Regulatory Agency (MHRA) that people who undergo metal-on-metal implants should receive follow-up care. We would like to share our clinical experience of the past several years. 

 

We are a clinical specialist physiotherapist in orthopaedics, and a consultant orthopaedic surgeon, respectively. Hip articulations have become a major public health issue, due to the complications associated with the wear of the implants. Early detection of adverse reactions to the implant is imperative to avoid long-term damage to the bone and soft tissues around the joint, thus improving the outcomes of revision surgery. The MHRA has recently updated its guidelines on the follow up of metal-on-metal articulations. It recommends an annual follow-up for symptomatic and asymptomatic patients, for the lifetime of the implant. 

 

This will inevitably put increased pressure on NHS service providers.

 

In 2011, University Hospital Southampton NHS Trust set up a metal-on-metal review clinic for patients identified from hospital databases. A band 8a clinical specialist physiotherapist (Alison Wakefield) runs a weekly clinic in which patients are reviewed with a history, examination and plain x-ray. An Oxford hip score and whole blood cobalt and chromium metal ions are obtained at each assessment. 

 

Patients unable to attend the clinic are offered telephone follow-up, with an x-ray request made at their local hospital and a blood metal ion request form sent by post.  

 

They are given a direct email contact for results, queries or problems. Patients are referred to the consultant clinic if they have any of the following: signs of adverse reaction to metal debris (ARMD) on MRI or ultrasound scan, bony changes on x-ray, rising blood cobalt/chromium ions or a change in symptoms with pain.

 

To date, 545 patients have been identified as requiring follow up for metal-on-metal articulations in our trust. 

 

These include 310 hip resurfacings and 235 large-head metal-on-metal total hip replacements. Follow-up has been achieved in 89 per cent of the patients identified by the MHRA criteria.