Patient Specific Modeling of Stage II Flatfoot Deformity Before and After Surgical Correction

Adult Acquired Flatfoot Deformity (AAFD) is a degenerative disease characterized by chronic changes in the joint alignment of the bones of the foot leading to significant pain and dysfunction. The early stages of the disease are thought to involve primarily the mechanical degradation of the soft-tissue support structures of the foot, namely the spring ligament, talocalcaneal interosseous ligaments, fibers of the anterior deltoid, and the long and short plantar ligaments, as well as a functional loss in posterior tibialis tendon (PTT) strength. [1] These changes manifest clinically as midfoot collapse, forefoot abduction, and valgus tilting hindfoot. [1–3] Various surgical corrections exist for Stage II AAFD to restore more normal biomechanical function to the foot. Treatment selection is most often based on clinical outcomes and surgeon preference. However, the optimal procedure(s) for an individual patient is unknown. Computer Aided Design (CAD) approaches offer advantages for evaluating foot function as well as the ability to predict pre-operatively the outcome of corrective procedures. This study developed a 3D patient specific computer model of the lower leg from a diagnosed Stage II flatfoot patient and evaluated its ability to predict foot function pre- and post-operatively through agreement with clinically relevant radiographic joint angles.