Assessment of Osteochondral Lesions of the Talus with Ultrasonography a Prospective Study with Computed Tomography Arthrography as the Gold Standard

Abstract

The purpose of this study was to evaluate the reliability of ultrasonography (US) for the diagnosis and characterization of osteochondral lesions of the talus (OLT), compared with computed tomography arthrography (CTA) as the gold standard. Eighty-one patients were enrolled from May 2018 to May 2019, consulting initially for ankle instability. US and CTA were performed the same day for each patient by an experienced skeletal radiologist. Images were analyzed in consensus. The primary outcome, detection of OLT, was calculated with Cohen’s kappa method test. Secondary outcomes were localization and size of osteochondral lesions. Four patients were positive on US (4.9%); 12 lesions were detected by CTA (14.8%). No false positives were found by US. Predominant locations were zones 4 (41.7%) and 6 (25%). Average surface area of OLT on US was 24.2 and 79.2 mm2 on CTA. Specificity for OLT detection by US was 100% and sensitivity 33%. Agreement factor kappa was 0.46 (Z = 1.96; po = 0.9; pc = 0.82). OLT size was significantly different (p > 0.5) between US and CTA. US had very high specificity (100%) but very low sensitivity (33%) for detecting OLT in ankle sprains, with no size correlation. Given the high US specificity, it would be useful to perform systematic anterior talus assessment in ankle injuries; any detection of OLT would enable prompt specialist referral of patients and CTA imaging.