MR arthrographic evaluation of the association between anterolateral soft tissue impingement and osteochondral lesion of the tibiotalar joint

Purpose: To retrospectively evaluate on magnetic resonance (MR) arthrography the relationship between joint capsule thickness and the stage of osteochondral lesions of the tibiotalar joint, as well as to evaluate the ankle joint capacity in patients with osteochondritis dissecans (OCD). Also, we demonstrate the unusual locations of osteochondral lesions of the ankle joint. Methods: MR arthrography images were analyzed by two staff radiologists in consensus. The normality of the data was analyzed by the Kolmogorov–Smirnov test. The Mann–Whitney U test was used to compare the relationship between joint capsule thickness and patient groups with OCD. Results: The anterolateral joint capsule thickness was significantly higher than the anteromedial and posterior joint capsule thickness in the OCD with loose bodies group (p = 0.049). Osteochondral defects were most commonly detected at the medial talar dome: in 29 of 37 patients (78.3%) in the OCD without loose bodies group and in 16 of 29 (55.2%) patients in the OCD with loose bodies group. The second most common localization of the osteochondral defect in the OCD with loose bodies group was the medial plafond of distal tibia [in 9 of 29 (31.1%) patients]. Conclusions: Clinical and radiological evidence of anterolateral impingement syndrome often accompanies stage 4 OCDs. OCDs of the distal tibial plafond are not rare in the ankle joint and are often associated with loose bodies. © 2019, Italian Society of Medical Radiology.