Newly Designed Foot Orthosis for Children with Residual Clubfoot After Ponseti Casting

ABSTRACT Orthoses can be used to accommodate residual clubfoot after Ponseti casting. Traditionally, orthoses are constructed using nonweightbearing casts or foam imprints. Technological advances in pressure analysis and in three-dimensional (3D) geometry assessment by computed tomographic (CT) scans can assist in designing and fabricating orthoses. The purpose of this study was to validate the new Milwaukee Foot Orthosis (MFO) using pressure metrics. Five typically developing children (mean age of 7.2 years) and five children with residual clubfoot deformities (eight residual clubfeet and mean age of 6 years) were recruited. All children with residual clubfoot had undergone Ponseti casting as an initial treatment. Each child underwent plantar pressure measurements and acquisition of 3D foot dimensions by a CT scanner. A computer-aided design (CAD) was used to develop a customized MFO for each of the five children. The MFO was manufactured for each foot with residual deformities using a rapid prototyping system. After the use of the MFO, pressure data showed significant reduction of maximal force, peak pressure, and other measurements at the heel and the lateral forefoot. There was significant reduction of the center of pressure (CoP) deviation in the forefoot (7.9%) and the midfoot (4.0%) compared with barefoot. The new MFO is effective in reducing residual clubfoot deformities, such as supination and adduction.