Medial collateral ligament complex of the ankle: MR appearance in asymptomatic subjects

Purpose: To prospectively characterize the spin-echo magnetic resonance ( MR) imaging appearance of the medial collateral ligament ( MCL) complex of the ankle in asymptomatic volunteers. Materials and Methods: 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. Results: 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. Conclusion: 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.