Chronic posterior tibial tendon insufficiency can result in acquired adult flatfoot deformity. This is a chronic foot condition where the soft-tissues (including the posterior tibial tendon, deltoid and spring ligaments) on the inside aspect of the ankle are subject to repetitive load during walking and standing. Over time these structures may become painful and swollen ultimately failing. When these supporting structures fail the result is a change in the alignment of the foot. This condition is typically associated with a progressive flatfoot deformity. This type of deformity leads to increased strain on the supporting structures on the inside of the ankle and loading through the outer aspect of the ankle and hind-foot. Both the inside and outside of the ankle can become painful resulting significant disability. This condition can often be treated without surgery by strengthening the involved muscles and tendons and by bracing the ankle. When non-operative treatment fails, surgery can improve the alignment replace the injured tendon. Alignment and function can be restored, however, the time to maximal improvement is typically six months but, can take up to a year.
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.
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.
First, both feet should be examined with the patient standing and the entire lower extremity visible. The foot should be inspected from above as well as from behind the patient, as valgus angulation of the hindfoot is best appreciated when the foot is viewed from behind. Johnson described the so-called more-toes sign: with more advanced deformity and abduction of the forefoot, more of the lateral toes become visible when the foot is viewed from behind. The single-limb heel-rise test is an excellent determinant of the function of the posterior tibial tendon. The patient is asked to attempt to rise onto the ball of one foot while the other foot is suspended off the floor. Under normal circumstances, the posterior tibial muscle, which inverts and stabilizes the hindfoot, is activated as the patient begins to rise onto the forefoot. The gastrocnemius-soleus muscle group then elevates the calcaneus, and the heel-rise is accomplished. With dysfunction of the posterior tibial tendon, however, inversion of the heel is weak, and either the heel remains in valgus or the patient is unable to rise onto the forefoot. If the patient can do a single-limb heel-rise, the limb may be stressed further by asking the patient to perform this maneuver repetitively.
Non surgical Treatment
Flatfoot deformity can be treated conservatively or with surgical intervention depending on the severity of the condition. When people notice their arches flattening, they should immediately avoid non-supportive shoes such as flip-flops, sandals or thin-soled tennis shoes. Theses shoes will only worsen the flatfoot deformity and exacerbate arch pain. Next, custom orthotics are essential for people with collapsed arches. Over-the-counter insoles only provide cushion and padding to the arch, whereas custom orthotics are fabricated to specifically fit the patient?s foot and provide support in the arch where the posterior tibial tendon is unable to anymore. Use of custom orthotics in the early phases of flatfoot or PTTD can prevent worsening of symptoms and prevent further attenuation or injury to the posterior tibial tendon. In more severe cases of flatfoot deformity an ankle foot orthosis (AFO) such as a Ritchie brace is needed. This brace provides more support to the arch and hindfoot rather than an orthotic but can be bulky in normal shoegear. Additional treatment along with use of custom orthotics is use of non-steroidal anti-inflammatories (NSAIDS) such as Advil, Motrin, or Ibuprofen which can decrease inflammation to the posterior tibial tendon. If pain is severe, the patient may need to be placed in a below the knee air walker boot for several weeks which will allow the tendon to rest and heal, especially if a posterior tibial tendon tear is noted on MRI.
In cases of PTTD that have progressed substantially or have failed to improve with non-surgical treatment, surgery may be required. For some advanced cases, surgery may be the only option. Symptomatic flexible flatfoot conditions are common entities in both the adolescent and adult populations. Ligamentous laxity and equinus play a significant role in most adolescent deformities. Posterior tibial tendon dysfunction (PTTD) is the most common cause of adult acquired flatfoot. One should consider surgical treatment for patients who have failed nonoperative therapy and have advancing symptoms and deformities that significantly interfere with the functional demands of daily life. Isolated Joint Fusion. This technique is used for well reducible flat foot by limiting motion at one or two joints that are usually arthritic. The Evans Anterior Calcaneal Osteotomy. This is indicated for late stage II adult acquired flatfoot and the flexible adolescent flatfoot. This procedure will address midtarsal instability, restore the medial longitudinal arch and reduce mild hind foot valgus. The Posterior Calcaneal Displacement Osteotomy (PCDO). This technique is indicated for late stage I and early stage II PTTD with reducible Calcaneal valgus. This is often combined with a tendon transfer. A PCDO is also indicated as an adjunctive procedure in the surgical reconstruction of the severe flexible adolescent flatfoot. Soft tissue procedure. On their own these are not very effective but in conjunction with an osseous procedure, soft tissue procedures can produce good outcome. Common ones are tendon and capsular repair, tendon lengthening and transfer procedures. Flat foot correction requires lengthy post operative period and a lot of patience. Your foot may need surgery but you might simply not have the time or endurance to go through the rehab phase of this type of surgery. We will discuss these and type of procedures necessary for your surgery in length before we go further with any type of intervention.