Treatment of pseudotumors after metal-on-metal hip resurfacing based on magnetic resonance imaging, metal ion levels and symptoms.

Peri-prosthetic pseudotumor formation can be a severe complication following Metal-on-Metal hip resurfacing arthroplasty (MoMHRA), with limited data on the optimal management of this complication. The aims of this study were (1) to evaluate the prevalence and severity of pseudotumors in a consecutive cohort of 248 MoMHRA (214 patients, mean follow-up 4.6 years, range: 1 - 8.2), and (2) to present a clinical guideline for their treatment based on severity grading with Metal Artefact Reduction Sequence Magnetic Resonance Imaging, metal ion levels and symptoms. Pseudotumor prevalence was 36.3%: 61 mild, 25 moderate and four were graded severe. Five revisions followed, all in symptomatic patients with elevated metal ion levels. Pseudotumor severity grading allowed us to be conservative with revision surgery for mild and moderate MoM disease.