What is a common cause of allograft dislodgement after Evans procedure?

• A. Disruption of long plantar ligament
• B. Disruption of spring ligament
• C. Deltoid ligament rupture
• D. Calcaneal fracture

Answer: (A)

The main idea is that graft stability after an Evans lateral column lengthening relies on intact plantar restraints that hold the graft in place. The long plantar ligament runs from the calcaneus to the bases of the metatarsals and, along with the plantar fascia, helps form and support the plantar arch. If this ligament is disrupted, the graft loses its plantar restraint and is free to migrate or dislodge from the osteotomy site. While the spring ligament, deltoid ligament, or a calcaneal fracture can affect hindfoot mechanics, they are not the primary structures securing the graft in the Evans procedure, making disruption of the long plantar ligament the most likely cause of graft dislodgement.