Predictive factors for residual equinovarus deformity following Ponseti treatment and percutaneous Achilles tenotomy for idiopathic clubfoot: a retrospective review of 50 cases followed for median 2 years

Abstract

Background and purpose: There is no consensus on how to predict residual equinovarus deformities after application of the Ponseti method. We assessed the prognostic value of clinical scoring systems, and also radiographic parameters that can be measured just before percutaneous Achilles tenotomy (PAT).

Method: We reviewed 50 cases of clubfoot in 35 patients who were treated using the Ponseti method, including PAT, to analyze the factors that are predictive of residual equinovarus deformities. Mean age at the time of PAT was 2.4 (1.4-3.5) months, and the mean follow-up period was 23 (9-61) months. We divided these cases into 2 groups according to the need for further surgery to treat the residual deformities.

Results: 40 feet with satisfactory results were included in group 1, whereas the remaining 10 feet that required further surgery for unsatisfactory residual deformities were included in group 2. We compared the initial Dimeglio and Pirani scores obtained before the first Ponseti casting, follow-up Pirani scores, and radiographic parameters determined just before PAT between these 2 groups. There was no statistically significant difference between the groups in terms of the initial Dimeglio and Pirani scores, although the follow-up Pirani scores and lateral tibiocalcaneal angle were higher and the lateral talocalcaneal angle was lower in group 2 at the time of PAT.

Interpretation: We conclude that the Pirani score, lateral tibiocalcaneal angle, and talocalcaneal angle, when assessed immediately before PAT, might be predictive factors for residual equinovarus deformity following Ponseti treatment for severe idiopathic clubfoot.

Radiographic measurement of the lateral tibiocalcaneal angle in each group of patients. A. A lateral tibiocalcaneal angle of 82° before PAT in a 3-month-old infant. B. The same infant at 15 months of age; the lateral tibiocalcaneal angle was 67°. This child was assigned to group 1. C. A lateral tibiocalcaneal angle of 118° before percutaneous Achilles tenotomy in a 3-month-old infant. D. The same infant at 12 months of age; the lateral tibiocalcaneal angle was 96° before selective soft tissue release was performed to treat the residual equinovarus deformity. This child was assigned to group 2.