ORIGINAL ARTICLES Determination of the Effective Site for Percutaneous Achilles Tenotomy in Ponseti Management of African Idiopathic Clubfoot Olalekan A. Anipole, MBBS* Lawrence M. Oginni, MBBS† Oluwagbemiga O. Ayoola, MBChB‡ Olayinka O. Adegbehingbe, MBChB† Oluwadare Esan, MBChB† Joseph O. Mejabi, MBBS# 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 6 SD AT thicknesses 1 and 2 cm from the calcaneal insertion in the study group were 2.4 6 0.7 mm and 2.1 6 0.7 mm, respectively, and in the control group were 2.5 6 0.7 mm and 2.3 6 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. (J Am Podiatr Med Assoc 111(6): 1-5, 2021) Idiopathic clubfoot is a congenital foot deformity comprising forefoot adduction, midfoot cavus, hindfoot varus, and ankle equinus. 1 It is that which occurs in an otherwise healthy baby. 2 It is one of the commonest congenital musculoskeletal abnormali- ties, with approximately 200,000 cases seen annu- ally in the developing world. 3 Its diagnosis is clinical. Several treatment modal- ities have been used in the treatment of this condition, ranging from nonoperative to operative procedures. Presently, nonoperative methods are preferred, among which the Ponseti method has gained universal acceptance with good outcomes. Morcuende et al 4 reported an initial correction rate of as much as 94%. It has also reduced the total cost of care and modified the pattern of surgery if *Department of Orthopaedics, Federal Medical Centre, Birnin Kebbi, Kebbi State, Nigeria. †Department of Orthopaedic Surgery and Traumatology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. ‡Department of Radiology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. #Department of Surgery, Federal Medical Centre, Keffi, Nasarawa State, Nigeria. Corresponding author: Olalekan A. Anipole, MBBS, Department of Orthopaedics, Federal Medical Centre, along Dukku Barrack Road, Birnin Kebbi, P.M.B 1126 Kebbi State, Nigeria (E-mail: anipoleola@gmail.com) Journal of the American Podiatric Medical Association  Vol 111  No 6  November/December 2021 1