Adult acquired flatfoot
is often a complex disorder, with diverse
symptoms and varying degrees of deformity and disability. There are several types of flatfoot, all of which have one characteristic in common-partial or total collapse (loss) of the arch. Other
characteristics shared by most types of flatfoot include Toe drift, where the toes and front part of the foot point outward. The heel tilts toward the outside and the ankle appears to turn in. A
short Achilles tendon or calf muscle, which causes the heel to lift off the ground earlier when walking and may act as a deforming force. In addition, other deformities such bunions and hammertoes
can occur and cause pain in people with flexible flatfoot. Health problems such as rheumatoid arthritis, diabetes and obesity can increase the risk of developing flatfoot and may (or may not) make it
more difficult to treat. This article provides a brief overview of the problems that can result in AAFD. Further details regarding the most common conditions that cause an acquired flatfoot and their
treatment options are provided in separate articles. Links to those articles are provided.
Women are affected by Adult Acquired Flatfoot four times more frequently than men. Adult Flatfoot generally occurs in middle to older age people. Most people who acquire the condition already have
flat feet. One arch begins to flatten more, then pain and swelling develop on the inside of the ankle. This condition generally affects only one foot. It is unclear why women are affected more often
than men. But factors that may increase your risk of Adult Flatfoot include diabetes, hypertension, and obesity.
Patients will usually describe their initial symptoms as "ankle pain", as the PT Tendon becomes painful around the inside of the ankle joint. The pain will become more intense as the foot flattens
out, due to the continued stretching and tearing of the PT Tendon. As the arches continue to fall, and pronation increases, the heel bone (Calcaneus) tilts into a position where it pinches against
the ankle bone (Fibula), causing pain on both the inside and outside of the ankle. As the foot spends increased time in a flattened, or deformed position, Arthritis can begin to affect the joints of
the foot, causing additional pain.
The adult acquired flatfoot, secondary to posterior tibial tendon dysfunction, is diagnosed in a number of ways with no single test proven to be totally reliable. The most accurate diagnosis is made
by a skilled clinician utilizing observation and hands on evaluation of the foot and ankle. Observation of the foot in a walking examination is most reliable. The affected foot appears more pronated
and deformed compared to the unaffected foot. Muscle testing will show a strength deficit. An easy test to perform in the office is the single foot raise. A patient is asked to step with full body
weight on the symptomatic foot, keeping the unaffected foot off the ground. The patient is then instructed to "raise up on the tip toes" of the affected foot. If the posterior tibial tendon has been
attenuated or ruptured, the patient will be unable to lift the heel off the floor and rise onto the toes. In less severe cases, the patient will be able to rise on the toes, but the heel will not be
noted to invert as it normally does when we rise onto the toes. X-rays can be helpful but are not diagnostic of the adult acquired flatfoot. Both feet - the symptomatic and asymptomatic - will
demonstrate a flatfoot deformity on x-ray. Careful observation may show a greater severity of deformity on the affected side.
Non surgical Treatment
The following is a summary of conservative treatments for acquired flatfoot. Stage 1, NSAIDs and short-leg walking cast or walker boot for 6-8 weeks; full-length semirigid custom molded orthosis,
physical therapy. Stage 2, UCBL orthosis or short articulated ankle orthosis. Stage 3, Molded AFO, double-upright brace, or patellar tendon-bearing brace. Stage 4, Molded AFO, double-upright brace,
or patellar tendon-bearing brace.
Stage two deformities are less responsive to conservative therapies that can be effective in mild deformities. Bone procedures are necessary at this stage in order to recreate the arch and stabilize
the foot. These procedures include isolated fusion procedures, bone grafts, and/or the repositioning of bones through cuts called osteotomies. The realigned bones are generally held in place with
screws, pins, plates, or staples while the bone heals. A tendon transfer may or may not be utilized depending on the condition of the posterior tibial tendon. Stage three deformities are better
treated with surgical correction, in healthy patients. Patients that are unable to tolerate surgery or the prolonged healing period are better served with either arch supports known as orthotics or
bracing such as the Richie Brace. Surgical correction at this stage usually requires fusion procedures such as a triple or double arthrodesis. This involves fusing the two or three major bones in the
back of the foot together with screws or pins. The most common joints fused together are the subtalar joint, talonavicular joint, and the calcaneocuboid joint. By fusing the bones together the
surgeon is able to correct structural deformity and alleviate arthritic pain. Tendon transfer procedures are usually not beneficial at this stage. Stage four deformities are treated similarly but
with the addition of fusing the ankle joint.