Flat Top Talus: Complication of Ponseti Method or Overcorrection?

Purpose Deformation of talus in idiopathic clubfoot is a common problem both surgically and after treatment with the Ponseti technique, although the cause of deformation and its clinical impact on the function of the ankle is not yet known. The goal of this research was to evaluate factors leading to talar dome deformation (flat-top talus) after the Ponseti technique Methods This was a single-center, cross-sectional study. Fifty patients with virgin idiopathic clubfoot were enrolled from our consecutive series of data from August 2017 to January 2018 from our clubfoot patients who completed their casting and bracing protocol. Weight-bearing lateral X-rays of the ankle were examined in patients to determine the flattening of the talus dome and its correlation with age, sex, BMI, number of casts, and casting period. In these patients, the frequency of tenotomy and its relationship to the flat top talus was also examined. Results The study included a total of 50 children, of which 36 (72%) were boys and 14 (28%) were girls. The mean age, height, weight, and BMI of the children were 5.06 ± 0.79 years, 101.6 ± 6.34 cm, and 19.7 ± 1.57 kg, respectively. No significant difference between the normal and flat top talus category was found in age and BMI (p=0.611 and 0.997, respectively). Whereas, relative to normal children, the children who had flat-top talus were on casts for a longer period of time (median: 9 vs. 6 weeks, p=0.026). In addition, a higher proportion of children with more than six casts developed flat-top talus than those with fewer than six casts (69.2% vs. 30.8%, p=0.005). After treatment, a total of 13 (26%) patients developed flat top talus, of which 11 (84.6%) were boys and two (15.4%) were girls (p=0.303). No substantial association between tenotomy and flat top talus (p=0.340) could be identified. Conclusion Flat top talus is a complication of improper manipulation specifically correlated with the number of Ponseti casts applied. Maintenance of cast treatment for more than three months may result in flat-top talus with no significant association with tenotomy of the tendoachilles.