Medial Collateral Ligament Complex of the Ankle: MR Appearance in Asymptomatic Subjects

Abstract

To prospectively characterize the spin-echo magnetic resonance (MR) imaging appearance of the medial collateral ligament (MCL) complex of the ankle in asymptomatic volunteers. The study was approved by institutional review board. Informed consent was obtained. MR images in 56 asymptomatic subjects (29 women, 27 men; mean age, 40.7 years; range, 23-60 years) were analyzed by two musculoskeletal radiologists. Visibility and signal intensity characteristics were analyzed for deep (anterior and posterior tibiotalar ligaments [TTLs]) and superficial (tibionavicular ligament [TNL], tibiospring ligament [TSL], and tibiocalcaneal ligament [TCL]) components of the MCL complex. Thickness of ligaments was compared between sexes (Mann-Whitney U test). Associations between age and variables of signal intensity characteristics and morphology were evaluated with Kruskal-Wallis test. Anterior and posterior TTLs, TNL, TSL, and TCL were visible in 31 (55%), 56 (100%), 31 (55%), 56 (100%), and 49 (88%) subjects, respectively. On T1-weighted images, anterior and posterior TTLs, TNL, TSL, and TCL were more commonly of intermediate signal intensity than hypointense (77%, 100%, 93%, 50%, and 73% of subjects, respectively); on T2-weighted images, they were commonly hypointense (55%, 52%, 42%, 75%, and 78% of subjects, respectively). On T2-weighted images, posterior TTL had a striated appearance that was significantly associated with age (P = .004) in 89% of subjects: In subjects younger than 45 years, this striated appearance was present. On T1-weighted images, striation was present in 48% of subjects. Striation was uncommon in remaining ligaments. Mean thickness and range were 1.5 mm and 1-4 mm (anterior TTL), 8.2 mm and 6-11 mm (posterior TTL), 1.6 mm and 1-2 mm (TNL), 2.0 mm and 1-4 mm (TSL), and 1.2 mm and 1-3 mm (TCL). TNL (P = .001) and TSL (P = .003) were significantly thicker in men than in women. In asymptomatic volunteers, posterior TTL and TSL were always visible, but anterior TTL and TNL are only seen in approximately half of subjects. Posterior TTL has a typically striated appearance.