Adult acquired flatfoot deformity (AAFD), embraces a wide spectrum of deformities. AAFD is a complex pathology consisting both of posterior tibial tendon insufficiency and failure of the capsular and ligamentous structures of the foot. Each patient presents with characteristic deformities across the involved joints, requiring individualized treatment. Early stages may respond well to aggressive conservative management, yet more severe AAFD necessitates prompt surgical therapy to halt the progression of the disease to stages requiring more complex procedures. We present the most current diagnostic and therapeutic approaches to AAFD, based on the most pertinent literature and our own experience and investigations.
As discussed above, many health conditions 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 hold up the arch and support 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.
PTTD begins with a gradual stretching and loss of strength of the posterior tibial tendon which is the most important tendon supporting the arch of the human foot. Left untreated, this tendon will continue to lengthen and eventually rupture, leading to a progressive visible collapse of the arch of the foot. In the early stages, patients with PTTD will notice a pain and swelling along the inner ankle and arch. Many times, they are diagnosed with ?tendonitis? of the inner ankle. If the foot and ankle are not properly supported during this early phase, the posterior tibial tendon can rupture and devastating consequences will occur to the foot and ankle structure. The progressive adult acquired flatfoot deformity will cause the heel to roll inward in a ?valgus? or pronated direction while the forefoot will rotate outward causing a ?duckfooted? walking pattern. Eventually, significant arthritis can occur in the joints of the foot, the ankle and even the knee. Early diagnosis and treatment is critical so if you have noticed that one, or both, of your feet has become flatter in recent times come in and have it checked out.
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
Conservative treatment is indicated for nearly all patients initially before surgical management is considered. The key factors in determining appropriate treatment are whether acute inflammation and whether the foot deformity is flexible or fixed. However, the ultimate treatment is often determined by the patients, most of whom are women aged 40 or older. Compliance can be a problem, especially in stages I and II. It helps to emphasise to the patients that tibialis posterior dysfunction is a progressive and chronic condition and that several fittings and a trial of several different orthoses or treatments are often needed before a tolerable treatment is found.
Surgical treatment should be considered when all other conservative treatment has failed. Surgery options for flatfoot reconstruction depend on the severity of the flatfoot. Surgery for a flexible flatfoot deformity (flatfoot without arthritis to the foot joints) involves advancing the posterior tibial tendon under the arch to provide more support and decrease elongation of the tendon as well as addressing the hindfoot eversion with a osteotomy to the calcaneus (surgical cut in the heel bone). Additionally, the Achilles tendon may need to be lengthened because of the compensatory contracture of the Achilles tendon with flatfoot deformity. Flatfoot deformity with arthritic changes to the foot is considered a rigid flatfoot. Correction of a rigid flatfoot deformity usually involves surgical fusion of the hindfoot joints. This is a reconstructive procedure which allows the surgeon to re-position the foot into a normal position. Although the procedure should be considered for advanced PTTD, it has many complications and should be discussed at length with your doctor.