Acquired adult flatfoot deformity (AAFD) is a progressive flattening of the arch of the foot that occurs as the posterior tibial tendon becomes insufficient. It has many other names such posterior tibial tendon dysfunction, posterior tibial tendon insufficiency and dorsolateral peritalar subluxation. This problem may progress from early stages with pain along the posterior tibial tendon to advanced deformity and arthritis throughout the hindfoot and ankle.
Adult acquired flatfoot is caused by inflammation and progressive weakening of the major tendon that it is responsible for supporting the arch of the foot. This condition will commonly be accompanied by swelling and pain on the inner portion of the foot and ankle. Adult acquired flatfoot is more common in women and overweight individuals. It can also be seen after an injury to the foot and ankle. If left untreated the problem may result in a vicious cycle, as the foot becomes flatter the tendon supporting the arch structure becomes weaker and more and more stretched out. As the tendon becomes weaker, the foot structure becomes progressively flatter. Early detection and treatment is key, as this condition can lead to chronic swelling and pain.
The types of symptoms that may indicate Adult-Acquired Flat Foot Deformity include foot pain that worsens over time, loss of the arch, abnormal shoe wear (excessive wearing on the inner side of shoe from walking on the inner side of the foot) and an awkward appearance of the foot and ankle (when viewed from behind, heel and toes appear to go out to the side). It is important that we help individuals recognize the early symptoms of this condition, as there are many treatment options, depending upon the severity, the age of the patient, and the desired activity levels.
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
Flatfoot can be treated with a variety of methods, including modified shoes, orthotic devices, a brace or cast, anti-inflammatory medications or limited steroid injections, rest, ice, and physical therapy. In severe cases, surgery may be necessary.
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.