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.
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.
Patients often experience pain and/or deformity at the ankle or hindfoot. When the posterior tibial tendon does not work properly, a number of changes can occur to the foot and ankle. In the earlier stages, symptoms often include pain and tenderness along the posterior tibial tendon behind the inside of the ankle. As the tendon progressively fails, deformity of the foot and ankle may occur. This deformity can include progressive flattening of the arch, shifting of the heel so that it no longer is aligned underneath the rest of the leg, rotation and deformity of the forefoot, tightening of the heel cord, development of arthritis, and deformity of the ankle joint. At certain stages of this disorder, pain may shift from the inside to the outside aspect of the ankle as the heel shifts outward and structures are pinched laterally.
It is of great importance to have a full evaluation, by a foot and ankle specialist with expertise in addressing complex flatfoot deformities. No two flat feet are alike; therefore, “Universal” treatment plans do not exist for the Adult Flatfoot. It is important to have a custom treatment plan that is tailored to your specific foot. That starts by first understanding all the intricacies of your foot, through an extensive evaluation. X-rays of the foot and ankle are standard, and MRI may be used to better assess the quality of the PT Tendon.
Non surgical Treatment
This condition may be treated with conservative methods. These can include orthotic devices, special shoes, and bracing. Physical therapy, rest, ice, and anti-inflammatory medication may be prescribed to help relieve symptoms. If the condition is very severe, surgical treatment may be needed.
If initial conservative therapy of posterior tibial tendon insufficiency fails, surgical treatment is considered. Operative treatment of stage 1 disease involves release of the tendon sheath, tenosynovectomy, debridement of the tendon with excision of flap tears, and repair of longitudinal tears. A short-leg walking cast is worn for 3 weeks postoperatively. Teasdall and Johnson reported complete relief of pain in 74% of 14 patients undergoing this treatment regimen for stage 1 disease. Surgical debridement of tenosynovitis in early stages is believed to possibly prevent progression of disease to later stages of dysfunction.