Posterior Tibial Tendon Dysfunction
1. Posterior tibial tendon dysfunction encompasses a spectrum of pathology ranging from isolated tendinosis to fixed flatfoot deformity. 2. Preoperative planning should involve assessment of flexible versus fixed deformity, correction of hindfoot and for
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Dean Wang and Nelson F. SooHoo
Keywords
Flatfoot • Posterior tibial tendon dysfunction • Pes planus • Reconstruction • Salvage
Introduction Posterior tibial tendon (PTT) dysfunction encompasses a spectrum of pathology ranging from isolated tendinosis to secondary acquired adult flatfoot deformity that can be flexible or fixed depending on the severity. The characteristic of flatfoot deformity is flattening of the arch due to hindfoot valgus with abduction of the forefoot (Fig. 10.1a). Current management approaches include operative modalities with some persistent controversy regarding optimal treatment of flexible deformities. Pathology of the posterior tibial tendon is more common in females and has a peak incidence at age 55 years [5]. Repetitive microtrauma to the posterior tibial tendon leads to inflammatory or degenerative response that ultimately leads to tendon dysfunction [3]. With increasing age, the elastic compliance of the tendon decreases,
D. Wang, MD • N.F. SooHoo, MD (*) Department of Orthopedic Surgery, UCLA School of Medicine, Santa Monica, CA, USA e-mail: [email protected]
predisposing the tendon to damage. Because the PTT has a limited excursion of only 2 cm, any insult that lengthens the tendon has an adverse effect on its function [14]. Obesity, congenital flatfoot, and high impact sports have been associated with development of posterior tibial tendon dysfunction presumably as a result of higher repetitive mechanical stresses on the tendon [8, 15, 16]. A hypovascular zone in the tendon has been described by many at the level of the medial malleolus, the region at which tendon failure most often occurs [12, 25]. Diabetes and steroid use have also been linked to posterior tibial tendon dysfunction further supporting the theory of hypovascularity as a contributing factor [15]. Adult-acquired flatfoot deformity secondary to PTT dysfunction begins with progressive weakness of the tendon which leads to the supporting capsular and ligamentous structures beginning to fail. Downward and medial pressure of the talar head stretches the spring ligament complex, resulting in plantar sag and forefoot abduction through the talonavicular joint. Additionally, weakness of tendon function results in the transverse tarsal joint being unable to lock. As a result, the talonavicular joint becomes the
© Springer-Verlag Berlin Heidelberg 2016 H.-G. Jung (ed.), Foot and Ankle Disorders: An Illustrated Reference, DOI 10.1007/978-3-642-54493-4_10
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Fig. 10.1 (a) Physical examination findings of stage II deformity with left heel valgus and forefoot abduction. (b) Standing lateral radiographs of both feet demonstrate increase talar flexion with loss of the talus-1st metatarsal alignment on the left foot compared to the normal right foot.
(c) Standing anteroposterior radiographs of the foot demonstrate abduction of the foot with decreased talonavicular coverage. (d) Axial magnetic resonance image confirming tendon pathology with increased signal in the tendon s
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