School of Podiatric Medicine - Student Research

Document Type

Poster

Publication Date

Spring 2-24-2026

Abstract

This study evaluated whether discrepancies in tibial sesamoid position (TSP) between anteroposterior (AP) and sesamoid axial radiographs are associated with first-ray deformity parameters: first metatarsal rotation angle (MRA), sesamoid rotation angle (SRA), intermetatarsal angle (IMA), and hallux valgus angle (HVA). We hypothesized that increased frontal-plane external rotation of the first metatarsal would be the primary contributor to AP–axial TSP mismatch.

This secondary analysis used deidentified radiographs from Shibuya et al. (J Foot Ankle Surg. 2019). Adults aged 18–80 with measurable TSP on both AP and axial views were included; patients with prior foot trauma or osseous surgery were excluded. Only the most recent and right-sided radiographs were analyzed. Collected variables included AP and axial TSP, MRA, SRA, IMA, and HVA. Patients were categorized as having matched (“Same TSP”) or discrepant (“Discrepant TSP”) AP and axial TSP. Welch’s t-tests and multivariable logistic regression were performed.

Among 123 patients (60 Same; 63 Discrepant), the Same group had a mean TSP of 3.2. In the Discrepant group, mean TSP was 4.2 on AP and 3.1 on axial views; nearly all showed lower axial TSP. The Discrepant group demonstrated higher MRA, SRA, and IMA on bivariate analysis, while HVA did not differ. In multivariable analysis, only MRA remained independently associated with TSP discrepancy.

Greater first metatarsal external rotation is associated with AP–axial TSP mismatch, suggesting increased instability of the metatarsal-sesamoid complex and implications for surgical planning in hallux valgus correction.

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