Subtle Dynamic Flatfoot Deformity: Is It More Than Stage I PTTD?

Abstract

Adult acquired flat foot has long been considered synonymous with posterior tibial tendon dysfunction (PTTD), first described by Johnson and Strom in 1989. This is based on the authors’ clinical experience and a small case series described in 1994. However, there is little evidence that PTTD invariably leads to flat foot deformity. We propose a rethinking of stage I PTTD as subtle dynamic flatfoot, wherein adult acquired flat foot is driven largely by gastrocsoleus tightness and progressive hypermobility of the first ray. Clinical assessment should consist of careful evaluation of first ray stability as well as the spring ligament, tibiotalar range of motion, and impingement over the sinus tarsi. We present our preferred treatment strategy. Nonoperatively, patients are managed with a stretching program focused on the hamstrings and gastrocsoleus as well as the use of orthotics and night splint. Operative treatment consists of treatment of any areas of impingement and correcting the biomechanics of the foot and ankle with a Strayer, Cotton Osteotomy, and lateral column lengthening. Resection of the accessory facet of the talus is optional depending on preoperative symptoms.