In a Medical Device Alert issued this week, UK’s competent authority the MHRA has issued specific and detailed guidance on the management of patients with all-metal (metal-on-metal, MoM) hips.
The Alert, which can be found here provides the agency’s interpretation of the facts surrounding the problem as well as specifying teh actions required in order to manage it. Most notably it states that the action required is to “Put updated systems in place for the follow-up and investigation of patients implanted with MoM hip replacements.”
The Alert specifically points out that this new guidance replaces that given in previous issuances from the agency.
Highlights from the Alert are:
- “The majority of patients implanted with MoM hip replacements have well functioning hips and are thought to be at a low risk of developing serious problems.”
- “A small number of patients implanted with these hips may, however, develop progressive soft tissue reactions to the wear debris associated with MoM articulations. The debris can cause soft tissue necrosis and adversely affect the results of revision surgery. The MHRA’s clinical orthopaedic experts are of the opinion that early revision of poorly performing MoM hip replacements should give a better revision outcome.”
There follows a detailed appendix providing procedural guidance for the management of all M0M hip prosthesis types identified as at risk. The list of implants is divided into four categories, which are resurfacing components, stemmed hips with smaller femoral heads, larger femoral heads and specifically all types of DePuy ASR hip. Of note is that asymptomatic patients in the large femoral head and ASR group will require further monitoring in contrast to the resurfacing and small head group in which the full raft of tests is only mandated in symptomatic patients.