MARS MRI Characteristics of Adverse Local Tissue Reactions in Taper Corrosion of Metal-on-Polyethylene THA Differ from Metal-on-Metal THA

Abstract Introduction Metal artifact reduction sequence (MARS) MRI has been recommended as a cross-sectional imaging modality in clinical evaluation of adverse tissue reactions (ALTR) in metal-on-metal (MoM) patients as well as metal-on-polyethylene (MoP) patients with taper corrosion. The aim of the study was to compare MARS MRI characteristics of ALTR in MoM THA with ALTR in MoP THA with modular taper corrosion. Methods A total of 197 patients with ALTR were evaluated: 1) 86 patients with MoM THA; 2) 37 MoP patients with head-neck taper corrosion; and 3) 74 MoP patient with neck-stem dual taper corrosion. MARS MRI scans were evaluated to identify location, size, type of adverse local tissue reaction (I-III), and associated ALTR synovitis (cystic, solid, and mixed). Results MARS MRI characteristics of ALTR was significantly different between the MoM and MoP groups (p=0.017). The MoP group demonstrated the highest proportion of thick-walled cystic masses type II (56.7% in head-neck taper corrosion MoP, 46.5% in dual taper corrosion MoP vs. 28.7% in MoM), while the MoM group had the highest proportion of thin-walled cystic masses type I. MoM implants (96.8%) were significantly more likely to have ALTR in multiple locations compared to both MoP groups (p=0.001). Conclusions This study demonstrates MARS MRI characteristics of ALTR differ by bearing type with a significantly higher percentage of mixed and solid type adverse local tissue reaction in the taper corrosion MoP THA compared to MoM THA. This information provides clinically useful information in evaluation of symptomatic MoP and MoM THA patients for adverse local tissue reactions.