Current concepts in adult acquired flatfoot deformity

Abstract

Adult acquired flatfoot deformity (AAFD) is associated with medial soft-tissue break of the posterior tibial tendon and ligaments of the arch. Failure of other ligaments that support the arch of the foot can occur before, during, or after tendon failure. Deformity at different levels may be directly related to specific structures that fail. Deformity often consists of a combination of plantar sag, midfoot abduction, and heel valgus. The cause of AAFD is multifactorial with the most common etiologic factor probably being a preexisting flatfoot. Other contributing factors include obesity and relative hypovascularity of the posterior tibial tendon. Currently, patients are grouped into four clinical stages that help describe the severity and flexibility of the deformity and guide treatment. AAFD is generally diagnosed through patient history, physical examination, and standing radiographs of the foot and ankle. Definitive treatment for stage I and initial treatment for the other stages should start with nonoperative measures. In general, surgical treatment algorithms should match individual components of the pathology or deformity with specific surgical treatments. Outcomes after treatment of AAFD have been documented. In general, preserving motion of the joints of the foot leads to better functional outcomes than fusion. Currently, the most controversy surrounds the surgical treatment of stage II deformity.