Accessory anterolateral talar facet as an etiology of painful talocalcaneal impingement in the rigid flatfoot: a new diagnosis

Abstract

A retrospective review identified six patients with seven painful rigid flatfeet. In each case, pain was localized laterally to an accessory facet of the anterolateral talus. cross-sectional imaging demonstrated no evidence of tarsal coalition. In five of the six, preoperative magnetic resonance imaging (MRI) was obtained and in each case demonstrated focal abutting bone marrow edema consistent with impingement between the accessory facet and the anterior calcaneus.Seven feet in six patients underwent resection of the accessory facet with additional subtalar joint-sparing reconstructive procedures. At an average follow-up of 11 months, clinical results were graded as four good and two fair.An association between this accessory facet and pain in the rigid flatfoot has not been previously reported. Obesity was universal and may represent a risk factor for facet impingement. At early follow-up, facet resection with subtalar joint-sparing flatfoot reconstruction provided good results with symptomatic and functional improvement in the majority of patients.

Figure 1a

Accessory anterolateral talar facet (F) in neutral hindfoot alignment.

Figure 1b

Impingement of the accessory facet (F) on the calcaneal neck (CN) with hindfoot eversion.

Figure 1c

Decompression of the sinus tarsi following accessory facet resection Figure 1. Intraoperative photos of a 16-year-old patient. (F - accessory anterolateral talar facet, ATFL – anterior talofibular ligament, P – peroneal tendons, DF – distal fibula, CN – calcaneal neck)

Figure 2

Clinical example. Figure 2a. (left) Preoperative radiograph (F – accessory facet). Figure 2b. (right) Postoperative radiograph following accessory facet resection, medial displacement calcaneal osteotomy, and calcaneocuboid distraction arthrodesis.

Figure 3

Clinical example. Figure 3a. (left) lateral radiograph of accessory anterolateral talar facet (F – accessory facet, B – dorsal talar beak). Figure 3b. (right) CT scan (F – accessory facet, B – dorsal talar beak).

Figure 4

Mr imaging demonstrating abutting bone marrow edema between the accessory facet (F)) and the calcaneal neck (N).

Figure 5

Histologic evaluation of excised accessory facet with hematoxylin and eosin (A – normal hyaline cartilage, B – early fibrocartilaginous change, C – thin, fissured cartilage, D – thickened subchondral bone with cysts).

Figure 6

Original description of the accessory anterolateral talar facet (facies externa accessoria)