Review Question - QID 5661

Over the last two years, an active 47-year-old woman has noticed progressive collapse of her left foot arch. She has achieved minimal relief with orthotics and aggressive physical therapy. On examination she has first tarsometatarsal instability with a flexible, non-tender, hindfoot. The Silfverskiold test reveals ankle joint dorsiflexion = +5° with knee extended and +5° with knee flexed. Additional examination findings can be seen in Figures A and B. Standing radiograph of the foot is shown in Figure C and D. What is the best next step in treatment?