The adult acquired flatfoot
(AAF) is a progressive, symptomatic (painful) deformity resulting from gradual stretch
(attenuation) of the tibialis posterior tendon as well as the ligaments that support the arch of the foot. Although the posterior tibialis tendon plays a significant role, this pathology has recently
been recognized as involving failure of other interosseous ligaments, such as the spring ligament. Due to the complexity of this pathology, posterior tibial tendon dysfunction (PTTD) is now referred
to as adult acquired flatfoot. Severe flatfoot associated with AAF can lead to other problems, such as plantar fascial tension, tendon pain, rearfoot subluxation, and ankle osteoarthritis
As discussed above, many different problems can create a painful flatfoot. Damage to the posterior tibial tendon is the most common cause of AAFD. The posterior tibial tendon is one of the most
important tendons of the leg. It starts at a muscle in the calf, travels down the inside of the lower leg and attaches to the bones on the inside of the foot. The main function of this tendon is to
support the arch of your foot when you walk. If the tendon becomes inflamed or torn, the arch will slowly collapse. Women and people over 40 are more likely to develop problems with the posterior
tibial tendon. Other risk factors include obesity, diabetes, and hypertension. Having flat feet since childhood increases the risk of developing a tear in the posterior tibial tendon. In addition,
people who are involved in high impact sports, such as basketball, tennis, or soccer, may have tears of the tendon from repetitive use. Inflammatory arthritis, such as rheumatoid arthritis, can cause
a painful flatfoot. This type of arthritis attacks not only the cartilage in the joints, but also the ligaments that support the foot. Inflammatory arthritis not only causes pain, but also causes the
foot to change shape and become flat. The arthritis can affect the back of the foot or the middle of foot, both of which can result in a fallen arch. An injury to the tendons or ligaments in the foot
can cause the joints to fall out of alignment. The ligaments support the bones and prevent them from moving. If the ligaments are torn, the foot will become flat and painful. This more commonly
occurs in the middle of the foot (Lisfranc injury), but can also occur in the back of the foot. Injuries to tendons of the foot can occur either in one instance (traumatically) or with repeated use
over time (overuse injury). Regardless of the cause, if tendon function is altered, the forces that are transmitted across joints in the foot are changed and this can lead to increased stress on
joint cartilage and ligaments. In addition to tendon and ligament injuries, fractures and dislocations of the bones in the midfoot can also lead to a flatfoot deformity. People with diabetes or with
nerve problems that limits normal feeling in the feet, can have collapse of the arch or of the entire foot. This type of arch collapse is typically more severe than that seen in patients with normal
feeling in their feet. In addition to the ligaments not holding the bones in place, the bones themselves can sometimes fracture and disintegrate without the patient feeling any pain. This may result
in a severely deformed foot that is very challenging to correct with surgery. Special shoes or braces are the best method for dealing with this problem.
Depending on the cause of the flatfoot, a patient may experience one or more of the different symptoms here. Pain along the course of the posterior tibial tendon which lies on the inside of the foot
and ankle. This can be associated with swelling on the inside of the ankle. Pain that is worse with activity. High intensity or impact activities, such as running, can be very difficult. Some
patients can have difficulty walking or even standing for long periods of time. When the foot collapses, the heel bone may shift position and put pressure on the outside ankle bone (fibula). This can
cause pain on the outside of the ankle. Arthritis in the heel also causes this same type of pain. Patients with an old injury or arthritis in the middle of the foot can have painful, bony bumps on
the top and inside of the foot. These make shoewear very difficult. Occasionally, the bony spurs are so large that they pinch the nerves which can result in numbness and tingling on the top of the
foot and into the toes. Diabetics may only notice swelling or a large bump on the bottom of the foot. Because their sensation is affected, people with diabetes may not have any pain. The large bump
can cause skin problems and an ulcer (a sore that does not heal) may develop if proper diabetic shoewear is not used.
Observe forefoot to hindfoot alignment. Do this with the patient sitting and the heel in neutral, and also with the patient standing. I like to put blocks under the forefoot with the heel in neutral
to see how much forefoot correction is necessary to help hold the hindfoot position. One last note is to check all joints for stiffness. In cases of prolonged PTTD or coalition, rigid deformity is
present and one must carefully check the joints of the midfoot and hindfoot for stiffness and arthritis in the surgical pre-planning.
Non surgical Treatment
Nonoperative therapy for posterior tibial tendon dysfunction has been shown to yield 67% good-to-excellent results in 49 patients with stage 2 and 3 deformities. A rigid UCBL orthosis with a medial
forefoot post was used in nonobese patients with flexible heel deformities correctible to neutral and less than 10? of forefoot varus. A molded ankle foot orthosis was used in obese patients with
fixed deformity and forefoot varus greater than 10?. Average length of orthotic use was 15 months. Four patients ultimately elected to have surgery. The authors concluded that orthotic management is
successful in older low-demand patients and that surgical treatment can be reserved for those patients who fail nonoperative treatment.
Flatfoot reconstruction (osteotomy). This is often recommended for flexible flatfoot condition. Flatfoot reconstruction involves cutting and shifting the heel bone into a more neutral position,
transferring the tendon used to flex the lesser toes (all but the big toe) to strengthen the posterior tibial tendon, and lengthening the calf muscle. Fusion (also known as triple arthrodesis).
Fusion involves fusing, or making stiff, three joints in the back of the foot the subtalar, talonavicular, and calcaneocuboid joints, to realign the foot and give it a more natural shape. Pins or
screws hold the area in place until it heals. Fusion is often recommended for a rigid flatfoot deformity or evidence of arthritis. Both of these surgeries can provide excellent pain relief and