Weber M, Snyder M, Workman K, et al. - In this study, variations between asymptomatic and symptomatic adverse local tissue reactions (ALTR) were compared in an observational cohort, including presentation, metal ion differences, and Metal Artifact Reduction Sequence (MARS) MRI findings. Researchers conducted a retrospective review of an observational cohort of 492 metal-on-polyethylene (MoP) total hip arthroplasty (THA) patients at increased risk for developing ALTR. This study enrolled a total of 94 patients who had undergone revision arthroplasty for ALTR. They compared presentation, metal ion levels, and imaging findings. This study's findings demonstrate that almost half of the MoP THA ALTR cases were asymptomatic. Between symptomatic and asymptomatic pseudotumor formation, cobalt levels could not differentiate. The data imply that it is necessary to risk-stratify individuals who could potentially have ALTR based on implant type, symptoms, ion levels, and MARS MRI.