Ultrasonographic Assessment of Deltoid Ligament Integrity in Ankle Fractures

Abstract

Background: Regardless of fibular status, the presence of a superficial deltoid ligament disruption or a combination of deep and superficial deltoid ligament disruption is central to the decision-making process in treating ankle fractures. The aims of the present study were to test whether ultrasonography can assess deltoid ligament integrity and to determine its validity and reliability by comparing it with gravity stress radiography. Methods: A consecutive series of 81 eligible patients with a nondisplaced or minimally displaced fibula fracture identified on a standard radiograph were prospectively enrolled. All patients underwent gravity stress radiography and ultrasonography. Image analysis included the layer type, integrity, and tear site of the deltoid ligament. Ultrasound validity and intra- and interobserver reliability were assessed by the interpretations of the first author and an independent observer who were blinded to the results. Results: Of all patients, 64 (79.0%) had a deltoid ligament disruption; most of the tears were of both the superficial and deep layers, partial and proximal attachment tears, and only 8 (12.5%) were complete tears. Patients with an intact deltoid ligament had a mean medial clear space (MCS) value of 2.7 ± 0.5 mm, and those with deltoid ligament tears had a mean MCS value of 5.9 ± 3.4 mm (P < .001). In a comparison between ultrasonography and gravity radiography, we found a sensitivity of 100% versus 97%, a specificity of 90% versus 100%, a positive predictive value of 97% versus 100%, and a negative predictive value of 100% versus 90%, respectively. The intra- and interobserver reliability was evaluated as almost perfect in all conditions. In a comparison between ultrasonography and gravity radiography, we found a sensitivity of 100% versus 97%, a specificity of 90% versus 100%, a positive predictive value of 97% versus 100%, and a negative predictive value of 100% versus 90%, respectively. Conclusion: Ultrasonography proved to be an accurate tool, allowing the identification of deltoid ligament disruption and the involved components in a more dynamic fashion. Its relative ease of use and lack of ionizing radiation make it a useful and confident technique that can be performed by an orthopedist. Level of Evidence: Level II, prospective comparative study.