Finite element stress analysis of the hindfoot after medial displacement calcaneal osteotomy with different translation distances.

The medial displacement calcaneal osteotomy (MDCO) is one of commonly used procedures to restore the hindfoot alignment of the flatfoot deformity. However, the selection of the amount of translation for MDCO and its biomechanical effect on the hindfoot was rarely reported. This study employs finite element analysis to investigate stress distribution in the hindfoot following MDCO across varying translation distances. An adult-acquired flatfoot deformity (AAFD) finite element (FE) model consisting of 16 bones, 56 ligaments, and soft tissues was used. MDCO procedure was simulated with the translation distance of 0 mm, 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, and 14 mm. Contact pressure on the plantar surface, the articular surface of the tibiotalar joint and the subtalar joint, and von Mises stress on the resection surface of the calcaneus under different translation distances were analyzed and compared. Results showed the MDCO reduces 12.46 to 33.32% peak contact pressure on the plantar surface, the tibiotalar joint, and the posterior facet of the subtalar joint, and shifts pressure from lateral to medial. But the difference in peak pressure for different translation distances larger than 4 mm was small. The MDCO also reduces the stress on the distal calcaneal resected surface. The study highlights the use of patient-specific computational modeling for preoperative plans.