A Guide To Conservative Care For Adult-Acquired Flatfoot

By Paul R. Scherer, DPM

Given the challenges of treating the common condition of adult-acquired flatfoot, this author reviews the literature and shares insights from his clinical experience. He discusses the proper staging of this condition and offers pertinent pearls on the use of conservative therapy. Aside from calcaneal fractures, adult-acquired flatfoot (AAF) may be the most difficult foot pathology to treat successfully. The complexity surrounding this pathology originates in the continued confusion about etiology, pathology, classification, pathomechanics and surgical and non-surgical treatment.    Accordingly, let us take a closer look at the various classifications of AAF, which has previously been referred to as posterior tibial tendon dysfunction (PTTD), and discuss the pathomechanics, prognosis and treatment options for non-surgical care.    The loss of the active and passive pull of the tibialis posterior tendon is strongly associated with the development of AAF but no one is quite sure of the entire pathomechanics of this clinical disaster.1 Added to the lack of understanding of the etiology is the mystery of why this problem seems to be increasing in prevalence over the last 20 years.2 Is it a result of the increased aging of the susceptible flatfooted population or are we as clinicians just starting to recognize the problem as an entity in itself?    Although the tibialis posterior must play an important role in the deformity, authors have begun since 1999 to describe this clinical scenario as adult-acquired flatfoot since the dysfunction or non-function of the tendon alone cannot account for the character and severity of the deformity and foot disability.2    In a previous article in Podiatry Today, Douglas Richie, Jr., DPM, postulated that “significant ligamentous rupture occurs” as the flattening of the longitudinal arch and disarticulation of the rearfoot develops along with the attenuation or complete destruction of the spring ligament, superficial deltoid, the plantar fascia and finally the long and short plantar ligaments.2 This may truly be the reason that repair or anastomosis of the tibialis posterior tendon alone is rarely effective in repairing the structural integrity of the foot. Recognizing that a multilevel and interrelated pathology is occurring is essential for the successful treatment of AAF, whether the treatment is surgical or non-surgical.    The progression from simple weakness of the tibialis posterior through ligamentous disruption and finally rearfoot subluxation creates various stages of pathology that are probably best to approach as individual entities. Treating the more advanced stages with methods one would use in the initial stages is not effective. Conversely, treating the early stages with therapies one would employ for the advanced subluxations is probably unpredictable and unsuccessful as well. Which system of classification offers the most appropriate and simplest decision marking opportunities for the clinician?    Although several authors attribute AAF to seropositive or seronegative arthropathies, the overwhelming majority are solely a local lower extremity phenomenon.3,4 Any valid classification should focus on this phenomenon as well as the contributing factors, such as obesity and gender, which seem to determine both the severity and accelerated progression of the deformity.

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