Abstract
Metal-on-metal hip arthroplasty has fallen out of favor because of complications arising from the articulation, namely metal sensitivity and accelerated wear. These complications can lead to early/mid-term failures from pain, osteolysis, implant loosening, and pseudotumor formation.
However, it has become clearer that MOM total hip arthroplasty behaves differently from MOM hip resurfacing, due to the additional junctions present in the total hip arthroplasty setting. Garbuz et al have demonstrated in a randomised controlled trial that MOM THA has significantly higher metal ion levels than MOM hip resurfacing. Clinical results of a MOM THA compared with a MOM HR using the same articulation also demonstrate significantly poorer results with the THA.
Newer literature has also shown that corrosion occurs at the taper junction of a THA due to the dissimilar metals. These corrosion products are likely what are causing a higher incidence of adverse local tissue reactions. Because a hip resurfacing implant is a monoblock ball, there is no taper junction of dissimilar metals that has the potential for corrosion.
National registry studies have also demonstrated a difference in the survival curves of MOM THA vs. hip resurfacing. MOM HR, in select patient groups, has a lower revision rate at 10 years than traditional metal-on-poly THA. Thus, to eliminate MOM hip resurfacing as a treatment option is akin to “throwing the baby out with the bathwater”, which the presenter deeply opposes.
