The anatomical location of cystic pseudotumors and muscle atrophy in metal-on-metal resurfacing hip arthroplasty is related to the surgical approach used for implantation. A subgroup analyses of a randomized controlled trial

How to Manage Metallosis: A Retrospective Cohort Analysis after Revision Hip Surgery

“…Approximately 10% of the patients referred for MRI could not undergo the scan due to claustrophobia, various contraindications (e.g., presence of a pacemaker, stent placement incompatible with magnetic fields, or metal shrapnel in the body), or not specified "personal reasons". Soft tissue magnetic resonance imaging was considered pathological if the following findings were present: fluid collections, masses, or muscle changes [33]. A radiological classification system was used to classify these masses according to their degree of solidity, dividing them into three groups: Type I (thin-walled cystic masses with cyst wall < 3 mm), Type II (thick-walled cystic masses and cyst wall > 3 mm), and Type III (solid masses) [34].…”

“…Diagnosis was completed via blood tests: erythrocyte sedimentation rate (ESR) using the Westergren method (normal values 0-20 mm/h) [35], C-reactive protein (CRP) using high-sensitivity CRP tests (normal values ≥2-≤10 mg/L) [36], and cobalt (Co) (≤1.0 µg/L) and chromium (Cr) (≤1.4 µg/L) serum ion levels assessed via Quantitative Inductively Coupled Plasma-Mass Spectrometry [37]. Patients diagnosed with metallosis were divided into three groups on the basis of patient reports and clinical examination Soft tissue magnetic resonance imaging was considered pathological if the following findings were present: fluid collections, masses, or muscle changes [33]. A radiological classification system was used to classify these masses according to their degree of solidity, dividing them into three groups: Type I (thin-walled cystic masses with cyst wall < 3 mm), Type II (thick-walled cystic masses and cyst wall > 3 mm), and Type III (solid masses) [34].…”