Catherine L. McCarthy MD, Presenter: Nothing to Disclose

David Wilson MD, Abstract Co-Author: Nothing to Disclose

To prospectively evaluate the findings and diagnostic accuracy of ultrasound in anterolateral ankle impingement (ALI) with clinical and arthroscopic correlation.

Fifteen male footballers with chronic anterolateral ankle pain were referred for ultrasound with clinical ALI (n=6) or a control condition (n=9). Ultrasound was performed prior to arthroscopy by a musculoskeletal radiologist using an ATL HDI 5000 scanner. Arthroscopy was performed by a foot and ankle surgeon under general anaesthesia. Assessment included the anterolateral gutter for abnormal synovial tissue (synovitic lesion), lateral ligament integrity and tibiotalar joint. Arthroscopic appearances were correlated with ultrasound findings.

Ultrasound examination detected a mass in the anterolateral gutter in 6 footballers with clinical ALI (100%) and 2 control patients (22%). Arthroscopic confirmation of anterolateral synovitis and fibrosis was present in all 8 cases (100%). The synovitic lesion appeared as a soft tissue mass of mixed echogenicity which extruded anteriorly with compression of the distal fibula and tibia. Lesions measured >10mm in footballers with ALI and <10mm in the control group. No increased blood supply was present with doppler imaging. Additional ultrasound findings included anterior talofibular ligament injury (n=8), osseous spurs (n=4) and tibiotalar joint effusion (n=5). Anterolateral synovitic tissue was accurately identified in the absence of an effusion (n=3). No synovitic lesion was detected at ultrasound or arthroscopy in the remaining 7 control patients [lateral ligamentous complex injury (n=4), osteochondral fracture (n=1), intra-articular bodies (n=1) and osteoarthritis (n=1)].

Ultrasound is accurate in detecting anterolateral synovitic lesions and associated lateral ligament injuries. Doppler studies suggest synovitic lesions are composed of fibrosis rather than active synovial inflammation. Findings in two control subjects suggest synovitic lesions do not necessarily imply the presence of clinical ALI which may be determined by the size of the synovitic mass. Ultrasound findings with clinical correlation can direct arthroscopic examination and surgical debridement.

McCarthy, C, Wilson, D, Anterolateral Ankle Impingement: Findings and Diagnostic Accuracy with Ultrasound Imaging.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4406657.html