A Guide To Conservative Care For Adult Flatfoot
A short ankle-foot orthotic (AFO) is helpful for stage II PTTD. This is able to control and restrict the subtalar joint more than orthotics alone. Use a tall AFO in stage III cases because the rearfoot can no longer be passively corrected to neutral. This tall AFO is able to prevent pronation during push off. The AFO also stabilizes the mediolateral movement of the ankle and limits excursion of the posterior tibial tendon by preventing plantarflexion and pronation.14
There are numerous types of AFOs that are options. One common AFO is the Arizona brace. This brace reduces rearfoot valgus and midfoot collapse. The Richie brace is another effective AFO, which clinicians can use to help address the early stages of posterior tibial tendon dysfunction.14
The patellar tendon bearing brace is an option to consider for elderly patients. This redistributes weight to the patellar tendon, medial tibial flare and popliteal area.1
Iontophoresis with dexamethasone is a physical therapy modality. While this option is not as commonly employed as bracing options, iontophoresis can provide effective relief of inflammation to the PTT. There are no documented risks of tendon rupture with this modality and one may use this as a substitute for the controversial steroid injections into the tendon sheath.13
To further determine which treatment options are helpful for patients with various stages of flatfoot, see “Recommended Treatments For Different Flatfoot Stages” at top right.
Other Considerations In Managing Flatfoot
Stretching of the gastroc-soleus complex is also important to consider. A tight heel cord increases the levering upward on the calcaneus and increases tension on the plantar fascia and ligamtents.15 When a flatfoot deformity occurs, the Achilles tendon assumes a position lateral to the subtalar joint axis and the gastroc-soleus shortens over time.3 Thordarson demonstrated that the Achilles tendon has a threefold greater effect on the deformation of the arch than the PTT has on supporting the arch.16
Equinus is an essential piece to the puzzle of adult flatfoot that one should treat in order to reduce the pain and deformity. Adding a heel lift to orthotics or bracing will also help eliminate the equinus component to the flatfoot deformity.
The peroneus brevis is another muscle that one should consider when evaluating adult flatfoot. Mizel and colleagues evaluated 10 patients with loss of both the peroneal tendon and the posterior tibial tendon due to common peroneal nerve palsy.17 This study showed that after five years, there were no patients who developed a flatfoot deformity. The authors concluded that the posterior tibial tendon and the peroneus brevis provided the balance of the foot medially and laterally. Since these tendons were not functioning, neither provided unopposed force. With no unopposed force, a rearfoot valgus did not result. The authors determined from this result that dysfunction of the posterior tibial tendon alone was not enough to cause a flatfoot deformity.
Tarsal coalition can result in a rigid flatfoot that causes a static foot deformity. The talocalcaneal and calcaneonavicular joints are common joints involved in tarsal coalition. Accommodative orthotics are first line treatment for flatfoot caused by tarsal coalition.18
Conservative treatment is often able to decrease pain and the progression of flatfoot deformity. Early detection and treatment of posterior tibial tendon dysfunction can keep the deformity from progressing to further stages in the adult flatfoot scheme. Therefore, it is important to do a thorough history and physical exam with radiographic studies. Surgical correction is indicated for both complete posterior tibial tendon rupture and progressive deformity of the foot.
Should tenosynovitis persist after an extended period of conservative treatment, one should consider surgical correction as well. It is important to evaluate the patient thoroughly to be certain that one has explored the proper treatment methods.