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.
Flat footedness, most people who develop the condition already have flat feet. With overuse or continuous loading, a change occurs where the arch begins to flatten more than before, with pain and swelling developing on the inside of the ankle. Inadequate support from footwear may occasionally be a contributing factor. Trauma or injury, occasionally this condition may be due to fracture, sprain or direct blow to the tendon. Age, the risk of developing Posterior Tibial Tendon Dysfunction increases with age and research has suggested that middle aged women are more commonly affected. Other possible contributing factors – being overweight and inflammatory arthritis.
Often, this condition is only present in one foot, but it can affect both. Adult acquired flatfoot symptoms vary, but can swelling of the foot’s inner side and aching heel and arch pain. Some patients experience no pain, but others may experience severe pain. Symptoms may increase during long periods of standing, resulting in fatigue. Symptoms may change over time as the condition worsens. The pain may move to the foot’s outer side, and some patients may develop arthritis in the ankle and foot.
In the early stages of dysfunction of the posterior tibial tendon, most of the discomfort is located medially along the course of the tendon and the patient reports fatigue and aching on the plantar-medial aspect of the foot and ankle. Swelling is common if the dysfunction is associated with tenosynovitis. As dysfunction of the tendon progresses, maximum pain occurs laterally in the sinus tarsi because of impingement of the fibula against the calcaneus. With increasing deformity, patients report that the shape of the foot changes and that it becomes increasingly difficult to wear shoes. Many patients no longer report pain in the medial part of the foot and ankle after a complete rupture of the posterior tibial tendon has occurred; instead, the pain is located laterally. If a fixed deformity has not occurred, the patient may report that standing or walking with the hindfoot slightly inverted alleviates the lateral impingement and relieves the pain in the lateral part of the foot.
Non surgical Treatment
Nonoperative therapy for adult-acquired flatfoot is a reasonable treatment option that is likely to be beneficial for most patients. In this article, we describe the results of a retrospective cohort study that focused on nonoperative measures, including bracing, physical therapy, and anti-inflammatory medications, used to treat adult-acquired flatfoot in 64 consecutive patients. The results revealed the incidence of successful nonsurgical treatment to be 87.5% (56 of 64 patients), over the 27-month observation period. Overall, 78.12% of the patients with adult-acquired flatfoot were obese (body mass index [BMI] = 30), and 62.5% of the patients who failed nonsurgical therapy were obese; however, logistic regression failed to show that BMI was statistically significantly associated with the outcome of treatment. The use of any form of bracing was statistically significantly associated with successful nonsurgical treatment (fully adjusted OR = 19.8621, 95% CI 1.8774 to 210.134), whereas the presence of a split-tear of the tibialis posterior on magnetic resonance image scans was statistically significantly associated with failed nonsurgical treatment (fully adjusted OR = 0.016, 95% CI 0.0011 to 0.2347). The results of this investigation indicate that a systematic nonsurgical treatment approach to the treatment of the adult-acquired flatfoot deformity can be successful in most cases.
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.