Chronic posterior tibial tendon insufficiency can result in acquired adult flatfoot deformity. This is a chronic foot condition where the soft-tissues (including the posterior tibial tendon, deltoid and spring ligaments) on the inside aspect of the ankle are subject to repetitive load during walking and standing. Over time these structures may become painful and swollen ultimately failing. When these supporting structures fail the result is a change in the alignment of the foot. This condition is typically associated with a progressive flatfoot deformity. This type of deformity leads to increased strain on the supporting structures on the inside of the ankle and loading through the outer aspect of the ankle and hind-foot. Both the inside and outside of the ankle can become painful resulting significant disability. This condition can often be treated without surgery by strengthening the involved muscles and tendons and by bracing the ankle. When non-operative treatment fails, surgery can improve the alignment replace the injured tendon. Alignment and function can be restored, however, the time to maximal improvement is typically six months but, can take up to a year.
As the name suggests, adult-acquired flatfoot occurs once musculoskeletal maturity is reached, and it can present for a number of reasons, though one stands out among the others. While fractures, dislocations, tendon lacerations, and other such traumatic events do contribute to adult-acquired flatfoot as a significant lower extremity disorder, as mentioned above, damage to the posterior tibial tendon is most often at the heart of adult-acquired flatfoot. One study further elaborates on the matter by concluding that ?60% of patients [presenting with posterior tibial tendon damage and adult-acquired flatfoot] were obese or had diabetes mellitus, hypertension, previous surgery or trauma to the medial foot, or treatment with steroids?.
Symptoms are minor and may go unnoticed, Pain dominates, rather than deformity. Minor swelling may be visible along the course of the tendon. Pain and swelling along the course of the tendon. Visible decrease in arch height. Aduction of the forefoot on rearfoot. Subluxed tali and navicular joints. Deformation at this point is still flexible. Considerable deformity and weakness. Significant pain. Arthritic changes in the tarsal joints. Deformation at this point is rigid.
Examination by your foot and ankle specialist can confirm the diagnosis for most patients. An ultrasound exam performed in the office setting can evaluate the status of the posterior tibial tendon, the tendon which is primarily responsible for supporting the arch structure of the foot.
Non surgical Treatment
Footwear has an important role, and patients should be encouraged to wear flat lace-up shoes, or even lace-up boots, which accommodate orthoses. Stage I patients may be able to manage with an off the shelf orthosis (such as an Orthaheel or Formthotics). They can try a laced canvas ankle brace before moving to a casted orthosis. The various casted, semirigid orthoses support the medial longitudinal arch of the foot and either hold the heel in a neutral alignment (stage I) or correct the outward bent heel to a neutral alignment (stage II). This approach is meant to serve several functions: to alleviate stress on the tibialis posterior; to make gait more efficient by holding the hindfoot fixed; and thirdly, to prevent progression of deformity. Devices available to do this are the orthosis of the University of California Biomechanics Laboratory, an ankle foot orthosis, or a removable boot. When this approach has been used, two thirds of patients have good to excellent results.
In cases of PTTD that have progressed substantially or have failed to improve with non-surgical treatment, surgery may be required. For some advanced cases, surgery may be the only option. Your foot and ankle surgeon will determine the best approach for you.