is a general term used to describe a person whose arches are slowly dropping to the ground, aka
fallen arches. Adult-acquired flatfoot deformity can be caused by several factors, but the most common is abnormal functioning of the posterior tibial tendon in the foot and ankle. The posterior
tibial tendon is the primary tendon that supports the arch. If this tendon begins to elongate from a sustained, gradual stretch over a long period of time, then the arch will progressively decrease
until full collapse of the arch is noted on standing. What makes this tendon elongated? Biomechanical instability of the foot such as over-pronation or an accessory bone at the insertion site of the
tendon are the primary causes for posterior tibial tendon dysfunction.
Overuse of the posterior tibial tendon is often the cause of PTTD. In fact, the symptoms usually occur after activities that involve the tendon, such as running, walking, hiking, or climbing
Symptoms of pain may have developed gradually as result of overuse or they may be traced to one minor injury. Typically, the pain localizes to the inside (medial) aspect of the ankle, under the
medial malleolus. However, some patients will also experience pain over the outside (lateral) aspect of the hindfoot because of the displacement of the calcaneus impinging with the lateral malleolus.
This usually occurs later in the course of the condition. Patients may walk with a limp or in advanced cases be disabled due to pain. They may also have noticed worsening of their flatfoot
The diagnosis of tibialis posterior dysfunction is essentially clinical. However, plain radiographs of the foot and ankle are useful for assessing the degree of deformity and to confirm the presence
or absence of degenerative changes in the subtalar and ankle articulations. The radiographs are also useful to exclude other causes of an acquired flatfoot deformity. The most useful radiographs are
bilateral anteroposterior and lateral radiographs of the foot and a mortise (true anteroposterior) view of the ankle. All radiographs should be done with the patient standing. In most cases we see no
role for magnetic resonance imaging or ultrasonography, as the diagnosis can be made clinically.
Non surgical Treatment
What are the treatment options? In early stages an orthotic that caters for a medially deviated subtalar joint ac-cess. Examples of these are the RX skive, Medafeet MOSI device. Customised de-vices
with a Kirby skive or MOSI adaptation will provide greater control than a prefabricated device. If the condition develops further a UCBL orthotic or an AFO (ankle foot orthotic) could be necessary
for greater control. Various different forms of surgery are available depending upon the root cause of the issue and severity.
Until recently, operative treatment was indicated for most patients with stage 2 deformities. However, with the use of potentially effective nonoperative management , operative treatment is now
indicated for those patients that have failed nonoperative management. The principles of operative treatment of stage 2 deformities include transferring another tendon to help serve the role of the
dysfunctional posterior tibial tendon (usually the flexor hallucis longus is transferred). Restoring the shape and alignment of the foot. This moves the weight bearing axis back to the center of the
ankle. Changing the shape of the foot can be achieved by one or more of the following procedures. Cutting the heel bone and shifting it to the inside (Medializing calcaneal osteotomy). Lateral column
lengthening restores the arch and overall alignment of the foot. Medial column stabilization. This stiffens the ray of the big toe to better support the arch. Lengthening of the Achilles tendon or
Gastrocnemius. This will allow the ankle to move adequately once the alignment of the foot is corrected. Stage 3 acquired adult flatfoot deformity is treated operatively with a hindfoot fusion
(arthrodesis). This is done with either a double or triple arthrodesis - fusion of two or three of the joints in hindfoot through which the deformity occurs. It is important when a hindfoot
arthrodesis is performed that it be done in such a way that the underlying foot deformity is corrected first. Simply fusing the hindfoot joints in place is no longer acceptable.