Patient Specific Modeling of a Stage II Flatfoot Population

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 hallmark of this disease is the functional loss in posterior tibialis tendon (PTT) strength though mechanical degradation of passive support structures of the foot have also been implicated, namely the spring ligament, talocalcaneal interosseous ligaments, fibers of the anterior deltoid, and the long and short plantar ligaments. [1] Clinically, AAFD patients present with midfoot collapse, forefoot abduction, and valgus tilting of the hindfoot and the magnitudes of these deformities are most often graded using plane radiographs in the mediolateral (ML), oblique anteroposterior (AP) and posteroanterior (PA) views. [1–3] The objective of this study was to develop a population of patient-matched rigid-body kinematic models using a standardized methodology that can be used to predict pathologic foot function with agreement between patient and model assessed through clinically relevant radiographic joint angles.

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

ASME 2012 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2012-80366 ◽

2012 ◽

Author(s):

E. Meade Spratley ◽

Erika A. Matheis ◽

Curtis W. Hayes ◽

Robert S. Adelaar ◽

Jennifer S. Wayne

Keyword(s):

Computer Aided Design ◽

Stage Ii ◽

Patient Specific ◽

Mechanical Degradation ◽

Spring Ligament ◽

Before And After ◽

Foot Function ◽

Anterior Deltoid ◽

Patient Specific Modeling ◽

Aided Design

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.

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