Classification of midfoot break using multi-segment foot kinematics and pedobarography

Midfoot break (MFB) is a foot deformity that can occur when ankle dorsiflexion is restricted due to muscle spasticity or contractures, causing abnormal increased motion through the midfoot. MFB has been previously described in terms of forefoot (FF) and hindfoot (HF) motion in the sagittal plane. The purpose of this study was to further classify MFB by describing FF and HF motion in the coronal and transverse planes along with plantar pressures, with the goal of optimizing treatment of this deformity. Three-dimensional foot kinematics were assessed using a multi-segment foot model in children with MFB (n=30) and children with no foot or gait abnormalities (n=30). The MFB group was subdivided into three categories: (1) Pronated MFB, (2) Supinated MFB and (3) Flat Foot MFB. Unique patterns of plantar pressures and foot kinematics were identified for each MFB group. The Pronated MFB group had increased medial midfoot pressures, increased forefoot pronation, and increased external forefoot rotation (forefoot abductus). The Supinated MFB group had increased lateral midfoot pressures, increased forefoot supination, and increased internal forefoot rotation (forefoot adductus). In the Flat Foot MFB group, midfoot pressures were increased and distributed uniformly between the medial and lateral sides, forefoot pronation was increased, and internal forefoot rotation was present. By combining this new information with previously reported methods of measuring sagittal plane kinematics of MFB, it is now possible to characterize midfoot break in terms of severity and foot-floor contact pattern.