Pediatric PCFD Exhibits Less Forefoot Abduction and Middle Facet Subluxation Than Non-Pediatric PCFD: A Weight-Bearing CT Analysis

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Progressive Collapsing Foot Deformity (PCFD) is a symptomatic, complex, three-dimensional foot deformity that can occur in feet that were previously neutrally aligned or in those with congenital/pediatric flat feet. Once collapsed, it become...

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Main Authors: Antoine Acker MD, Erik Jesus Huanuco Casas MD, Tommaso Forin Valvecchi MD, Emily Joan Luo BS, Sally Kuehn BS, Kepler A.M. Carvalho MD, Albert T. Anastasio MD, Mark E. Easley MD, Chien-Shun Wang MD, Cesar de Cesar Netto MD, PhD
Format: Article
Language:English
Published: SAGE Publishing 2024-12-01
Series:Foot & Ankle Orthopaedics
Online Access:https://doi.org/10.1177/2473011424S00423
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Summary:Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Progressive Collapsing Foot Deformity (PCFD) is a symptomatic, complex, three-dimensional foot deformity that can occur in feet that were previously neutrally aligned or in those with congenital/pediatric flat feet. Once collapsed, it becomes challenging to differentiate the initial foot shape. This study aims to evaluate differences in Weight-Bearing CT (WBCT) parameters among a cohort of symptomatic PCFD patients with a history of pediatric flat foot (= pediatric PCFD), without such a history (= non-pediatric PCFD), and a control group without PCFD. We hypothesized that pediatric PCFD would display distinct WBCT parameters compared to non-pediatric PCFD, particularly with less forefoot abduction and middle facet subluxation. Furthermore, we sought to identify which parameters are the most predictive of pediatric PCFD. Methods: This retrospective comparative study included adult patients with symptomatic PCFD. Pediatric PCFD was defined as patients with flat feet since childhood, and non-pediatric PCFD was defined as patients with no history of childhood flat foot. A total of 37 symptomatic pediatric PCFD patients were compared to 52 symptomatic non-pediatric PCFD patients and 11 control patients. All patients underwent foot/ankle WBCT scans. Using dedicated software, both manual and semi-automated 3D measurements were carried out for the various PCFD deformity categories (A-Hindfoot Valgus, B-Abduction, C-Arch Collapse, and D-Peritalar Subluxation). The data underwent normality testing with the Shapiro-Wilk method, and comparisons were made via Paired T-tests or Paired-Wilcoxon tests. A p-value threshold of 0.05 or below was deemed significant. To determine which factors affect the presence of rigidity in PCFD, a multivariate nominal regression analysis was conducted. A partition prediction model was employed to identify threshold values that most accurately determine “pediatric PCFD”. Results: All parameters showed significant differences compared to control, except for BMI. Compared to non-pediatric PCFD, the pediatric PCFD group showed significantly less deformity in classes A, B, C, and D (all p< 0.002) and became symptomatic at a younger age (p< 0.001). Compared to controls, pediatric PCFD measurements for HMA (p=0.053) and SF (p=0.07) were not statistically significant. Multivariate analysis indicated that axial TFM (p=0.005), MFS (p=0.013), and ST (p=0.03) were the best predictors of pediatric PCFD (R2: 0.27). The partition prediction model showed that an ST distance >0.24 mm, axial TFM >24.28, and MFS >43.7% can rule out pediatric PCFD with 95% confidence. Conclusion: This study showed that symptomatic pediatric PCFD presents with distinct WBCT parameters compared to symptomatic non-pediatric PCFD, notably exhibiting less forefoot abduction, less middle facet subluxation, and less hindfoot malalignment and seems to become symptomatic at a younger age. ST distance >0.24 mm, axial TFM >24.28, and MFS >43.7% could rule out a PCFD with “pediatric origin.” These results suggest that a different threshold should be set to assess PCFD in patients with flat feet since childhood.
ISSN:2473-0114