Background: Percutaneous Achilles tenotomy is an essential step in the Ponseti treatment of idiopathic clubfoot, with reported complications such as injury to the surrounding neurovascular structures and incomplete division of the Achilles tendon (AT). Knowledge of AT thickness would guide tenotomy blade insertion depth, obviating these related complications. We embarked on this study to ultrasonographically determine AT thickness at its different levels from the calcaneal insertion in children with idiopathic clubfoot.
Methods: This prospective comparative study consisted of two groups of children 4 years and younger: a study group of patients with clubfoot requiring tenotomy and a control group. Both groups underwent ultrasonographic evaluation of their AT. The ultrasonographic data collected include AT thickness 1 and 2 cm from the calcaneal insertion of the AT, thickness of the thinnest portion of the tendon, and the distance of this thinnest portion from the calcaneal insertion.
Results: Twenty-seven children with idiopathic clubfoot constituted the study group, and 23 children with no musculoskeletal deformity were enrolled in the control group. Mean ± SD AT thicknesses 1 and 2 cm from the calcaneal insertion in the study group were 2.4 ± 0.7 mm and 2.1 ± 0.7 mm, respectively, and in the control group were 2.5 ± 0.7 mm and 2.3 ± 0.7 mm, respectively. The average thickness of the thinnest portion of the AT along its length was 2 mm at 1.8 cm from the calcaneal insertion in both groups.
Conclusions: Safe and complete percutaneous tenotomy would most likely be achieved when performed 1.8 cm from the calcaneal insertion, where the corresponding average AT thickness of 2 mm would be a guide to determine the insertion depth of the tenotomy blade.