Sun Hwa Hong, Abstract Co-Author: Nothing to Disclose

Suk-Joo Hong MD, Presenter: Nothing to Disclose

Hak Jun Kim, Abstract Co-Author: Nothing to Disclose

Chang Ho Kang MD, Abstract Co-Author: Nothing to Disclose

Baek Hyun Kim MD, Abstract Co-Author: Nothing to Disclose

Eun-Young Kang MD, Abstract Co-Author: Nothing to Disclose

 The purpose of this study was to evaluate the predictability of ankle US and MRI for determining the need for surgical fixation in isolated lateral malleolar fractures.

Between February 2010 and March 2012, among consecutive 26 patients with isolated lateral malleolar fractures, 21 patients who underwent both ankle US and MRI were enrolled. (8 men and 13 women; mean 46.9 years, range 20-67 years). In the ankle US and MR studies, the integrity of the posterior tibiotalar ligament was analyzed with grading as follows: 0 (intact), 1 (partially ruptured), 2 (high-grade partially ruptured) or 3 (completely ruptured). Intraoperative valgus stress test was performed in all patients with medial clear space widening ≥ 4mm as the criteria of instability. Diagnostic performance of ankle US and MRI was evaluated by receiver operating characteristic analysis compared to the stress test. All patients with positive stress test underwent surgical treatment.

Nine patients with positive stress test underwent surgical treatment and 12 patients with negative stress test underwent conservative management. For ankle US and MRI, the sensitivity, specificity, average area under the curve were 0.8, 0.73, 0.868, and 0.9, 0.73, 0.873 with an optimal cut-off value of grade 2, respectively. When ankle instability was determined as over grade ligament tear, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of ankle US and MRI were 0.9, 0.73, 0.75, 0.89, 0.81 and 0.8, 0.73, 0.73, 0.8, 0.76, respectively. When the ankle instability was determined as over grade 3 ligament tear, those of ankle US and MRI were 0.4, 1.0, 1.0, 0.65, 0.71 and 0.5, 1.0, 1.0, 0.69, 0.76, respectively. Diagnostic accuracy of ankle US was higher than MRI when ankle instability was determined as over grade 2 ligament tear.

Both ankle MRI and US are predictable for the deltoid ligament injury in isolated lateral malleolar fracture. Both modalities can be used for preoperative determining whether surgical treatment is needed or not in the patients with isolated lateral malleolar fracture, in the place of intraoperative stress test.

Ankle MRI and US can be used in the place of intraoperative stress test.

Hong, S, Hong, S, Kim, H, Kang, C, Kim, B, Kang, E, Isolated Lateral Malleolar Fracture: Which Cases Should Be Operated?.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12029615.html