Combined Ankle and Midfoot Equinus Correction Using an Hexapod Miter Frame in a Patient with a Prior Contralateral Above-Knee Amputation

Complex post-traumatic equinus deformities of the foot and ankle are challenging for the orthopedic surgeon. Commonly associated with poor soft tissue and neurologic injuries, these acquired deformities can be located primarily at the ankle and hindfoot, but some patients may present with a two-component deformity including midfoot equinus also (Elomrani et al., Foot Ankle Int 26(3):251–255, 2005). Classically, the management of these patients included bone resection and talectomy using open approaches resulting in limb length discrepancies with a high rate of complications (Subik, Clin Podiatr Med Surg 35(4):481–496, 2018). Minimally invasive strategies should focus on preserving bone stock and avoiding approach-related complications. Gradual equinus correction using hexapod circular fixation with limited soft tissue procedures has been reported as a safe and effective method of treatment (Fuentes, Foot Ankle Int 42(12):1525–1535, 2021). Gradual correction of combined ankle/hindfoot and midfoot equinus can be done using a miter frame configuration to address both deformities independently (Wukish, Oper Tech Orthop 16:2–9, 2006; Cherkashin, Clin Podiatr Med Surg 35(4):423–442, 2018). We present a case of a 28-year-old male with a non-plantigrade severe rigid equinus deformity resulting in an inability to stand due to a prior contralateral above-knee amputation. The patient was treated using a hexapod miter frame configuration and subsequent tibiotalocalcaneal fusion after a plantigrade foot was achieved.