ABSTRACT
OBJECTIVE: Follow-up of pseudotumors observed with metal-artefact reducing sequence (MARS)-magnetic resonance imaging (MRI) following metal-on-metal total hip arthroplasty (MoMTHA) depends on how severe these pseudotumors are graded. Several pseudotumor grading systems for MARS-MRI have emerged but little is known of their validity. We studied the intra- and interobserver reliability of three different pseudotumor grading systems in a single cohort of MoMTHA. PATIENTS AND METHODS: Two experienced musculoskeletal radiologists independently used three different pseudotumor grading systems for classifying MARS-MRI results of the same cohort of 42 MoMTHA patients (49 hips, mean follow-up 5.2 years). Intraobserver and interobserver reliability for each grading system was measured using Cohen's kappa (κ). Variance in pseudotumor severity grading between systems was analyzed. RESULTS: Intraobserver reliability on grading pseudotumor severity with the Anderson, Matthies, and Hauptfleisch grading system scored 0.47, 0.10, and 0.35 (observer 1), and 0.75, 0.38, and 0.42 (observer 2), respectively. Interobserver reliability scores for pseudotumor severity were 0.58, 0.23, and 0.34, respectively. CONCLUSIONS: Intraobserver reliability for grading pseudotumor severity on MARS-MRI ranged from poor to good, dependent on observer and grading system used. Interobserver reliability scored best with the Anderson system. A more succinct pseudotumor severity grading system is needed for clinical use.
Subject(s)
Granuloma, Plasma Cell/etiology , Granuloma, Plasma Cell/pathology , Hip Prosthesis/adverse effects , Magnetic Resonance Imaging/methods , Metal-on-Metal Joint Prostheses/adverse effects , Osteitis/etiology , Osteitis/pathology , Adult , Aged , Cohort Studies , Female , Humans , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Male , Middle Aged , Observer Variation , Reproducibility of Results , Sensitivity and Specificity , Severity of Illness IndexABSTRACT
A 33-year-old man had a painful swelling in his left upper leg caused by a textiloma due to a ribbon fragment apparently left behind at a bicycle accident 7 years earlier when the handlebars had penetrated the leg.
