Deltoid ligament in acute ankle injury: MR imaging analysis

To identify the pattern of deltoid ligament injury after acute ankle injury and the relationship between ankle fracture and deltoid ligament tear by magnetic resonance imaging (MRI).

Thirty-six patients (32 male, and 4 female; mean age, 29.8 years) with acute deltoid ligament injury who had undergone MRI participated in this study. The deltoid ligament was classified as having 3 superficial and 2 deep components. An image analysis included the integrity and tear site of the deltoid ligament, and other associated injuries. Association between ankle fracture and deltoid ligament tear was assessed using Fisher's exact test (P < 0.05).

Of the 36 patients, 21 (58.3 %) had tears in the superficial and deep deltoid ligaments, 6 (16.7 %) in the superficial ligaments only, and 4 (11.1 %) in the deep ligaments only. The most common tear site of the three components of the superficial deltoid and deep anterior tibiotalar ligaments was their proximal attachments (94 % and 91.7 % respectively), and that of the deep posterior tibiotalar ligament (pTTL) was its distal attachment (82.6 %). The common associated injuries were ankle fracture (63.9 %), syndesmosis tear (55.6 %), and lateral collateral ligament complex tear (44.4 %). All the components of the deltoid ligament were frequently torn in patients with ankle fractures (tibionavicular ligament, P = 0.009).

The observed injury pattern of the deltoid ligament was complex and frequently associated with concomitant ankle pathology. The most common tear site of the superficial deltoid ligament was the medial malleolar attachment, whereas that of the deep pTTL was near its medial talar insertion.