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RA vs OA Radiographic Features — SCE Rheumatology MCQ

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EasyMusculoskeletal ImagingRA vs OA Radiographic FeaturesSCE Rheumatology

A 50-year-old man with established rheumatoid arthritis has hand radiographs showing periarticular osteopenia, marginal erosions at the second and third metacarpophalangeal joints, soft-tissue swelling and joint-space narrowing that is even across the width of each affected joint. Which interpretation best distinguishes this pattern from osteoarthritis?

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Correct answer: C — It supports RA because inflammatory cartilage loss is uniform, unlike focal OA narrowing

Uniform joint-space narrowing across an individual joint reflects diffuse inflammatory cartilage loss and supports RA, particularly when accompanied by marginal erosions, periarticular osteopenia and soft-tissue swelling. Here, “uniform” describes the pattern within the affected joint; it is not synonymous with bilateral symmetry. OA more typically produces focal or asymmetric narrowing in mechanically stressed areas, often with osteophytes, subchondral sclerosis and cysts. Effusion does not explain established radiographic joint-space loss, so A is incorrect. The pattern therefore has useful discriminatory value, excluding D. Gout usually preserves joint-space width until late disease and is characterised more typically by well-defined erosions with overhanging edges, making E incorrect.

Reference: Jacobson JA, Girish G, Jiang Y, Resnick D. Radiographic evaluation of arthritis: inflammatory conditions. Radiology. 2008;248(2):378–389. https://pubmed.ncbi.nlm.nih.gov/18641245/