To evaluate the ability of high resolution ultrasonography (US) in the diagnosis of erosive osteoarthritis (OA).
We enrolled 110 patients with signs and symptoms of inflammatory OA. Radiographs of both hands were performed in all patients; 22 were diagnosed as having erosive OA and 88 classical OA on the basis of typical erosive/non-erosive patterns. Distal and proximal interphalangeal joints of all patients were evaluated by US by 2 independent operators blinded to patient data. The examination was performed with a multiplanar scan technique, with joints in both maximal extension and flexion, using either a 14 MHz or 8-16 MHz broadband linear probe. The presence of articular bone surface irregularities defined as either marginal osteophytes or central erosions was recorded. Sensitivity, specificity, and likelihood ratios on the presence of erosions were calculated.
Central erosions were detected by US in 16 of 22 (72.7%) patients with erosive OA and in none of 88 patients with classical hand OA. Sensitivity and specificity for the detection of central erosions by US were 73% and 100%, respectively. The positive and negative likelihood ratios were 100% and 94%.
This is the first study to evaluate the presence of erosions in patients with erosive OA by US. Our results showed good concordance between US and radiography in detecting central joint erosions. We believe US may be considered a useful technique for the differential diagnosis between erosive OA and classical hand OA.