Distal Tibiofibular Syndesmotic Widening in Progressive Collapsing Foot Deformity

Abstract

Background: Lateral overload in progressive collapsing foot deformity (PCFD) takes place as hindfoot valgus, peritalar subluxation, and valgus instability of the ankle increase. Fibular strain due to chronic lateral impingement may lead to distraction forces over the distal tibiofibular syndesmosis (DTFS). This study aimed to assess and correlate the severity of the foot and ankle offset (FAO) as a marker of progressive PCFD with the amount of DTFS widening and to compare it to controls. Methods: In this case-control study, 62 symptomatic patients with PCFD and 29 controls who underwent standing weightbearing computed tomography (WBCT) examination were included. Two fellowship-trained blinded orthopedic foot and ankle surgeons performed FAO (%) and DTFS area measurements (mm2). DTFS was assessed semiautomatically on axial-plane WBCT images, 1 cm proximal to the apex of the tibial plafond. Values were compared between patients with PCFD and controls, and Spearman correlation between FAO and DTFS area measurements was assessed. P values of less than.05 were considered significant. Results: Patients with PCFD demonstrated significantly increased FAO and DTFS measurements in comparison to controls. A mean difference of 6.9% (P