Keys To The Biomechanical Evaluation Of The Symptomatic Adult - Acquired Flatfoot

foot, also known as posterior tibial tendon dysfunction, continues to be an intriguing subject that has received considerable attention from researchers and clinicians over the past decade. Recent publications from multiple disciplines have enabled podiatric physicians to modify or even change their approach to evaluation and treatment of this common disorder. Adult-acquired flatfoot is defined as a symptomatic, progressive deformity of the foot caused by a loss of dynamic and static supportive structures of the medial longitudinal arch. Although the condition begins with a loss of dynamic support from the posterior tibial tendon, the sequential ruptures of key ligaments in the ankle and hindfoot are the more important events leading to collapse of the arch and progressive disability of the patient. The adult-acquired flatfoot almost always begins with a preexisting flatfoot and has a predilection to affect females over the age of 40. When the foot functions in a valgus position in the hindfoot and carries excessive body mass, the posterior tibial tendon has increased friction and gliding resistance along the medial malleolar gliding pulley. The combination of this mechanical strain with other metabolic factors will lead to a progressive attenuation and rupture of the posterior tibial tendon. However, visible change or collapse of the foot will not occur with simple rupture of the posterior tibial tendon. Instead, the loss of the posterior tibial tendon will cause a dysfunction of the foot during gait, which will then place progressive strain on key ligamentous structures in the hindfoot. Increased load and strain will lead to rupture of the spring ligament, the interosseous talocalcaneal ligament and the long and short plantar ligaments. This will lead to a subluxation and triplane rotation of various joints that characterize the adultacquired flatfoot: valgus alignment of the hindfoot, collapse of the medial longitudinal arch and abduction of the forefoot.