Adult acquired flatfoot deformity or posterior tibial tendon dysfunction is a gradual but progressive loss of ones arch. The posterior tibial muscle is a deep muscle in the back of the calf. It has a
long tendon that extends from above the ankle and attaches into several sites around the arch of the foot. The muscle acts like a stirrup on the inside of the foot to help support the arch. The
posterior tibial muscle
stabilizes the arch and creates a rigid platform for walking and running. If the posterior tibial tendon becomes
damaged or tears the arch loses its stability and as a result, collapses causing a flatfoot. Adult flatfoot deformity can occur in people of all ages and gender however, it occurs most commonly in
sedentary middle aged to elderly females. There are several risk factors for posterior tibial tendon dysfunction that include: obesity, steroid use, systemic inflammatory diseases such as rheumatoid
arthritis, trauma, being born with a low arch, and diabetes. It occurs most commonly in one foot however, it can occur in both feet especially in people with systemic diseases such as diabetes and
A person with flat feet has greater load placed on the posterior tibial tendon which is the main tendon unit supporting up the arch of the foot. Throughout life, aging leads to decreased strength of
muscles, tendons and ligaments. The blood supply diminishes to tendons with aging as arteries narrow. Heavier, obese patients have more weight on the arch and have greater narrowing of arteries due
to atherosclerosis. In some people, the posterior tibial tendon finally gives out or tears. This is not a sudden event in most cases. Rather, it is a slow, gradual stretching followed by inflammation
and degeneration of the tendon. Once the posterior tibial tendon stretches, the ligaments of the arch stretch and tear. The bones of the arch then move out of position with body weight pressing down
from above. The foot rotates inward at the ankle in a movement called pronation. The arch appears collapsed, and the heel bone is tilted to the inside. The deformity can progress until the foot
literally dislocates outward from under the ankle joint.
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
Perform a structural assessment of the foot and ankle. Check the ankle for alignment and position. When it comes to patients with severe PTTD, the deltoid has failed, causing an instability of the
ankle and possible valgus of the ankle. This is a rare and difficult problem to address. However, if one misses it, it can lead to dire consequences and potential surgical failure. Check the heel
alignment and position of the heel both loaded and during varus/valgus stress. Compare range of motion of the heel to the normal contralateral limb. Check alignment of the midtarsal joint for
collapse and lateral deviation. Noting the level of lateral deviation in comparison to the contralateral limb is critical for surgical planning. Check midfoot alignment of the naviculocuneiform
joints and metatarsocuneiform joints both for sag and hypermobility.
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.
When conservative care fails to control symptoms and/or deformity, then surgery may be needed. The goal of surgical treatment is to obtain good alignment while keeping the foot and ankle as flexible
as possible. The most common procedures used with this condition include arthrodesis (fusion), osteotomy (cutting out a wedge-shaped piece of bone), and lateral column lengthening. Lateral column
lengthening involves the use of a bone graft at the calcaneocuboid joint. This procedure helps restore the medial longitudinal arch (arch along the inside of the foot). A torn tendon or spring
ligament will be repaired or reconstructed. Other surgical options include tendon shortening or lengthening. Or the surgeon may move one or more tendons. This procedure is called a tendon transfer.
Tendon transfer uses another tendon to help the posterior tibial tendon function more effectively. A tendon transfer is designed to change the force and angle of pull on the bones of the arch. It's
not clear yet from research evidence which surgical procedure works best for this condition. A combination of surgical treatments may be needed. It may depend on your age, type and severity of
deformity and symptoms, and your desired level of daily activity.