Effects of surgical correction for the treatment of adult acquired flatfoot deformity: A computational investigation

Abstract

Computational models of the foot/ankle complex were developed to predict the biomechanical consequences of surgical procedures that correct for Stage II adult acquired flatfoot deformity. Cadaveric leg and foot bony anatomy was captured by CT imaging in neutral flexion and imported to the modeling software. Ligaments were approximated as tension only springs attached at insertion sites. Muscle contraction of the gastrocnemius/soleus complex was simulated through force vectors and desired external loads applied to the model. Ligament stiffnesses were modified to reflect Stage II flatfoot damage, followed by integration of corrective osteotomies—medializing calcaneal osteotomy (MCO) and Evans and calcaneocuboid distraction arthrodesis (CCDA)—to treat flatfoot. Joint angles, tissue strains, calcaneocuboid contact force, and plantar loads were analyzed. The flatfoot simulation demonstrated clinical signs of disease evidenced by degradation of joint alignment. Repair states corrected these joint misalignments with MCO having greatest impact in the hindfoot, and Evans/CCDA having greatest effect in the mid- and forefoot. The lateral procedures unevenly strained plantar structures, while offloading the medial forefoot, and increased loading on the lateral forefoot, which was amplified by combining with MCO. The Evans procedure raised calcaneocuboid joint contact force to twice intact levels. Computational results are in agreement with clinical and experimental findings. The model demonstrated potential precursors to such complications as lateral tightness and arthritic development and may thus be useful as a predictor of surgical outcomes. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1047–1054, 2011

Validation of a population of patient‐specific adult acquired flatfoot deformity models

“…Computer aided design (CAD) offers advantages for evaluating foot function, diagnosing pathomechanics, and predicting pre‐operatively the outcome of corrective procedures. Accordingly, musculoskeletal CAD models have been developed to investigate biomechanical aspects of the intact and pathologic foot . Kinematic behavior in these models has been investigated using both deformable and rigid‐body mechanics.…”

Calcaneus osteotomy

“…A medializing calcaneal osteotomy was found to shift plantar forefoot loads from lateral to medial [18].…”

Computational Models of the Foot and Ankle for Pathomechanics and Clinical Applications: A Review

“…Computational analyses of surgeries have been adopted based on FE models 56 and multi-body musculoskeletal models. 8,36 The stress distribution of the plantar foot is an essential contributor of normal function of the foot. It was investigated under a balanced standing state using an FE model consisting of simplified bony structures, some of the ligaments, tendons and plantar fascia.…”

“…36 For more accurate representation of foot deformity, 3D patient-specific musculoskeletal models of six flatfoot patients were developed 50 to supplement the 2D radiographs for diagnosis and staging of this entity. The unipedal stance was simulated with the application of body weight and muscle contraction vectors based on EMG measures.…”