Abstracts

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E1070. Adult Acquired Flatfoot Deformity (AAFD): Beyond Posterior Tibial Tendon Tear
Authors
  1. Yvonne Cheung; Dartmouth Hitchcock Medical Center
  2. Jessica Sin; Dartmouth Hitchcock Medical Center
Background
Adult Acquired Flatfoot Disorder (AAFD) is relatively common. It is generally accepted that posterior tibial tendon (PTT) dysfunction is the major contributor to the deformity. In reality, isolated reconstruction of the PTT has produced disappointing long term surgical results. Moreover, other studies have shown that both PTT and several medial ligaments have to be interrupted to reproduce flat foot deformity in vivo. In other words, AAFD represents a cascade of failures of multiple medial support of the arch. The purpose of this exhibit is to show examples of combination injuries of the medial support so as to improve recognition and reporting prior to treatment of AAFD.

Educational Goals / Teaching Points
Review the normal anatomy of the medial supporting structures of the longitudinal arch of the foot. Discuss the Imaging criteria used to assess injury. Illustrate patterns of injury in AFFD

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
AFFD is characterized by collapse of the medial arch, hind-foot valgus and forefoot abduction. The PTT is the primary stabilizer of the medial arch. When the PTT fails, other medial stabilizers are stressed and injured. These medial supports include the spring ligament, the deltoid ligament, the talocalcaneal interosseous ligaments in the sinus tarsi and the plantar fascia, among others. MR imaging is effective in detection of both tendon and ligament injuries. It plays an important role in the detection of cumulative failures of the medial support of the arch. We will show MR cases of AAFD with various combinations of structural derangement. Common injury patterns include PTT and Spring ligament, PTT and superficial deltoid and PTT and sinus tarsi ligaments. We will include less common injury pattern such as PTT and plantar fascia interruption.

Conclusion
AAFD results from a cascade of derangement of multiple soft tissue support of the medial arch. The deformity frequently starts with PTT dysfunction, followed by injuries to other medial ligament support. This exhibit emphasizes the pattern of cumulative medial structural damage to help the radiologist better recognize all medial soft tissue failures in AAFD.