Abstract
Metal-on-metal (MoM) hip replacements were used for almost a decade before adverse reactions to metal debris (ARMD) were found to be a true clinical problem. Currently, there is a paucity of evidence regarding the usefulness of systematic screening for ARMD. We implemented a systematic review and meta-analysis to establish the prevalence of revision confirmed ARMD stratified by the use of different screening protocols in patients with MoM hip replacements. Five levels of screening were identified: no screening (level 0), targeted blood metal ion measurement and/or cross-sectional imaging (level 1), metal ion measurement without imaging (level 2), metal ion measurement with targeted imaging (level 3) and comprehensive screening (both metal ions and imaging for all; level 4). 122 studies meeting our eligibility criteria were included in analysis. These studies included 144 study arms: 100 study arms with hip resurfacings, 33 study arms with large-diameter MoM total hip replacements (THR), and 11 study arms with medium-diameter MoM THRs. For hip resurfacing, the lowest prevalence of ARMD was seen with level 0 screening (pooled prevalence 0.13%) and the highest with level 4 screening (pooled prevalace 9.49%). Pooled prevalence of ARMD with level 0 screening was 0.29% and with level 4 screening 21.3% in the large-diameter MoM THR group. In metaregression analysis of hip resurfacings, level 4 screening was superior with regard to prevalence of ARMD when compared with other levels. In the large diameter THR group level 4 screening was superior to screening 0,2 and 3. These outcomes were irrespective of follow-up time or study publication year. With hip resurfacings, routine cross-sectional imaging regardless of clinical findings is advisable. It is clear, however, that targeted metal ion measurement and/or imaging is not sufficient in the screening for ARMD in any implant concepts. However, economic aspects should be weighed when choosing the preferred screening level.
Highlights
In the late 1990s, advances in metallurgy and tribology led to a renewed interest in the use of metal-on-metal (MoM) bearings in total hip replacements (THR) [1]
A study was deemed eligible for our analysis if 1) it included an original patient cohort operated on with a single disclosed implant, 2) the implant used in the study was MoM hip resurfacing or MoM THR with a femoral head diameter of 36 mm or larger, and 3) the reasons for the revisions were clearly stated or the operative findings in the revision surgery were outlined
If the two studies included an identical study arm or a subcohort of a study arm but the more recent study implemented a different level of screening, both studies were included in our analyses since the primary aim of our study was to investigate the effect of screening levels on the prevalence of revision confirmed adverse reactions to metal debris (ARMD)
Summary
In the late 1990s, advances in metallurgy and tribology led to a renewed interest in the use of metal-on-metal (MoM) bearings in total hip replacements (THR) [1]. The use of large diameter (LD) femoral heads that mimick the native anatomy of the hip joint requires relatively thin, i.e., 4–8 mm acetabular components to prevent excessive acetabular bone resection. The concept of large-headed femoral components coupled with thin monoblock cups were rapidly adopted for MoM hip resurfacings. Preliminary results with these second generation MoM hip resurfacings were excellent, and the number of hip resurfacings surged in the early 2000s. LD MoM bearings for cementless stemmed THRs were adopted
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
