Singh Jatinder Pal, Loomba Sahil, Pun Bishika, Virmani Somesh
Department of Radiology, Medanta-The Medicity Hospital, Gurugram, Haryana, 122001, India.
Frontier Hospital Nepal, Kathmandu, Nepal.
Skeletal Radiol. 2025 Apr;54(4):893-898. doi: 10.1007/s00256-024-04781-6. Epub 2024 Sep 2.
The accessory anterolateral talar facet (AALTF) is an anatomical variation that broadens the apex of the lateral talar process. Studies have associated it with other tarsal coalitions as a cause of rigid painful flatfoot. However, a coalition of an AALTF has never been described before. With the advent of MRI, there has been an increase in the detection of these accessory facets. Nevertheless, owing to its small size and unfamiliarity, it is not easily identified. Proper assessment of imaging findings and associated conditions is needed to confirm the diagnosis. Imaging findings in a series of four patients with painful rigid flatfoot revealed the presence of an AALTF with adjacent marrow edema and reduced joint space. This was associated with hindfoot valgus and subfibular impingement. Radiographic suspicion of a non-osseous coalition of AALTF was raised, which was confirmed intraoperatively in one of the patients and demonstrated on CT and MR images in the other patients. This case series presents rare cases of non-osseous coalition of AALTF with a new radiographic sign, the 'reverse tip of the iceberg sign'.
距骨前外侧副小面（AALTF）是一种解剖变异，它使距骨外侧突的顶点变宽。研究已将其与其他跗骨联合视为僵硬性疼痛扁平足的一个病因。然而，此前从未描述过AALTF联合的情况。随着磁共振成像（MRI）的出现，这些副小面的检出率有所增加。尽管如此，由于其尺寸小且不为人熟悉，它并不容易被识别。需要对影像学表现及相关情况进行恰当评估以确诊。对一系列四名患有疼痛性僵硬扁平足患者的影像学检查发现，存在AALTF并伴有相邻骨髓水肿和关节间隙变窄。这与后足外翻和腓骨下撞击有关。影像学检查怀疑存在AALTF的非骨性联合，其中一名患者在术中得到证实，其他患者在CT和磁共振图像上也得到显示。本病例系列展示了罕见的AALTF非骨性联合病例，并伴有一种新的影像学征象，即“倒冰山尖征”。
