BACKGROUND: There are few long-term studies on the non-operative treatment of Stage II Posterior Tibial Tendon Dysfunction (PTTD). The purpose of this study is to describe the natural history and determine the efficacy of non-operative treatment of Stage II PTTD using clinical outcome scores. MATERIALS AND METHODS: Patients with Stage II PTTD treated with a Double Upright Ankle Foot Orthosis (DUAFO) with a minimum followup of 7 years were identified retrospectively. Patients were evaluated with the AOFAS Ankle/Hindfoot Score, SF-36, Foot Function Index (FFI), Visual Analog Scale (VAS) for pain, and a custom questionnaire in addition to a comprehensive physical examination. RESULTS: Thirty-three feet in 32 patients were included with an average followup of 8.6 years. Success defined as being brace-free and avoiding surgery was 69.7%. Five patients (15.2%) were unable to completely wean from a brace. Five patients went on to surgery. The mean AOFAS and FFI score was 78.4 and 18.4, respectively. Compared to national norms, SF-36 subscores for each age sub-category showed no significant difference in any of the age groups (p<0.05). Average VAS pain scale score was 1.9. Satisfaction was rated as "satisfied" in 20 patients (60.6%), "satisfied with minor reservations" in 11 patients (33.3%), partially satisfied in one (3.0%), and "unsatisfied" in one (3.0%). None of the patients rated as "satisfied with major reservations". CONCLUSION: Treatment of Stage II PTTD with a DUAFO has been shown to be a viable alternative to surgery with a high likelihood of adequate function, avoidance of surgery, and being brace-free at 7- to 10-year followup.