Does Casting Material Influence the Number of Casts Required Before Achilles Tenotomy in the Ponseti Treatment of Severe Idiopathic Clubfoot?

Background: Clubfoot represents a prevalent congenital deformity of the foot and ankle complex that may significantly compromise a child's walking ability. Contemporary treatment protocols encompass serial manipulations and casting procedures designed to achieve gradual correction of the deformity. Various casting materials have been employed in this therapeutic approach, with plaster of Paris and fiberglass constituting the two predominant options. This study aimed to evaluate the comparative effectiveness of these casting materials and determine whether material selection influences the rate of correction and the clinical indications, specifically regarding the number of casts required before percutaneous Achilles tenotomy. Methods: We conducted a retrospective analysis of prospectively collected data on paediatric patients treated at our tertiary-level institution with both plaster of Paris (POP) and semirigid fiberglass (SRF) by a single orthopaedic surgeon between 2010 and 2020. Treatment was initiated within the first 30 days of life (median age 12 days, range 0–28 days). To reduce confounding bias related to baseline aetiology (e.g., rigid syndromic feet), the primary comparative analysis was restricted to the idiopathic clubfoot subgroup. The Pirani score was used to assess deformity severity at each clinical visit. Results: A cohort of 84 patients (137 feet) was enrolled and treated, comprising patients with a Pirani score ≥ 4.5, excluding non-idiopathic cases. The mean number of casts required was 5.8 ± 1.0 for POP and 5.7 ± 1.2 for SRF, with no statistically significant difference (p = 0.91). Conclusions: Both plaster of Paris and semirigid fiberglass are highly effective casting materials for the initial phase of Ponseti treatment. Both achieve comparable correction sufficient to proceed with Achilles tenotomy. Accordingly, material selection should be guided by clinician proficiency, institutional cost-effectiveness, and patient comfort. Further investigation is needed to evaluate long-term outcomes and the relative benefits of each material in clubfoot management.