Dong-Ho Ha, Presenter: Nothing to Disclose

Sunseob Choi, Abstract Co-Author: Nothing to Disclose

Seong Kuk Yoon MD, Abstract Co-Author: Nothing to Disclose

Ki-Nam Lee MD, PhD, Abstract Co-Author: Nothing to Disclose

Sang Yun Lee, Abstract Co-Author: Nothing to Disclose

Suk Bin Seo, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to define and to measure the degree of lateral tilting of lateral malleolus on MR axial imaging as a predictor of an ATF tear.

We retrospectively reviewed ankle MRI examination from 2006 to 2010. MRI examinations of 44 patients with surgically proved ATF tear were evaluated. Patients with fractures were excluded. Ankle MRI examinations of 9 cases healthy persons were also evaluated. The foot was placed in the neural position. The degree of lateral tilting of lateral malleolus was measured at the level of fibular fossa. We also evaluated the thickness of ATF ligament, the discontinuity of ATF, other bony lesion such as osteochondral lesion of talus, os subfibulare.  

The lateral tilting of lateral malleolus was present in 26 of 44 (59 %) ATF tear patients. In these cases, mild thinning of with or without laxity of ATF ligament was present. The mean degree of lateral tilting of lateral malleolus was 22° ± 4 at the level of fibular fossa. In contrast, the mean degree of lateral tilting of lateral malleolus in heatlhy persons was 4° ± 2. Discontinuity of ATF ligament was not common and was present in 8 of 44 (18%) patients. Thickening or normal thickness of ligament was present in 5 of 44 (11%) patients.

Lateral tilting of lateral malleolus is relatively common and easily detectable MR imaging finding in ATF tear patients. Especially when mild thinning of ATF ligament is present, the lateral tilting of lateral malleolus is useful indirect sign of ATF tear.

Diagnosis of ATF ligament using MR imaging is often confusing due to anatomic variations of ATF ligament and fibrotic changes with joint capsule.

Ha, D, Choi, S, Yoon, S, Lee, K, Lee, S, Seo, S, Lateral Tilting of Lateral Malleolus at MR Imaging: Secondary Sign of Anterior Talofibular Ligament Tear.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9009756.html