Journal of the American Podiatric Medical Association
Evaluation of First Metatarsal Pronation and the Sesamoid Complex in Hallux Valgus: A Retrospective Exploratory Descriptive Radiographic Study Using a Modified Metatarso-Sesamoid View
By Mehmet Akif Şahin, Fatih Durgut, Kutbettin Dinçer and 2 others.
Abstract
Background
Hallux valgus (HV) is a three-dimensional deformity, and preoperative assessment of sesamoid position and first metatarsal rotation is important for surgical planning. Weight-bearing computed tomography (WBCT) enables three-dimensional assessment but was unavailable at our institution during the study period. Therefore, this study was a retrospective, exploratory, descriptive radiographic study of a modified weight-bearing metatarso-sesamoid (MS) projection, rather than a diagnostic-accuracy, comparative, or feasibility study.
Methods
Between 2022 and 2024, 18 patients (16 female, 2 male; mean age 46 years, range 25–75 years) with 22 feet scheduled for HV surgery were included. Preoperative weight-bearing AP, lateral, and modified MS radiographs were evaluated. The alpha angle, sesamoid rotation angle (SRA), AOFAS tibial sesamoid grade, and the pronation/subluxation (P/S) pattern were recorded on the modified MS view. Because the alpha angle and P/S classification were originally defined on axial CT, we applied them to plain radiography as an exploratory approach. We did not validate them against a CT reference standard. Intraobserver and interobserver measurement agreement on the same existing radiographs was assessed through repeated blinded measurements by the primary observer after four weeks and through independent evaluations by a second blinded observer. We quantified reliability using ICC(2,1), unweighted kappa, and linearly weighted kappa, with 95% CIs. Technical acquisition performance was recorded.