In recent years, the management of adult flatfoot has shifted from early surgical treatment to more conservative options for this commonly seen condition. Accordingly, these authors discuss the evaluation of adult flatfoot and enumerate various conservative methods to consider as initial treatment.
Adult flatfoot is a common problem we, as podiatrists, see every day. Without early identification of the problem, the flatfoot deformity can progress.
There has been a shift in protocol over the years from surgical treatment early on in the diagnosis of adult flatfoot to a more valiant attempt at conservative treatment. In 1997, Sferra and Rosenberg stated that “conservative management is a critical part of initial treatment of posterior tibial tendon insufficiency, especially in patients with advanced age, sedentary lifestyle and medical comorbidities that preclude surgical intervention.”1
In order to provide adequate treatment, whether it is surgical or conservative, to a patient with flatfoot, it is important to evaluate the patient clinically and radiographically to determine the cause of his or her flatfoot deformity. During the physical exam, the patient should stand during the observation. The physician should look for asymmetrical swelling, abduction of the forefoot and pes planus.
One should perform the bilateral heel rise test. When the heels appear asymmetrical or there is not a complete heel rise, consider posterior tibial tendon dysfunction (PTTD). Also perform the single limb heel rise. Incomplete inversion of the heel on toe rise or difficulty performing this test should alert the practitioner to a problem with the posterior tibial tendon.
During a seated exam, palpation of the tendon is necessary to evaluate soft tissue swelling and tenderness along the course of the tendon. To test motor strength, the podiatric physician should have the patient invert the foot against resistance with the foot plantarflexed to keep the tibialis anterior from substituting.2
Radiographic evaluation reveals lateral subluxation of the talonavicular joint, an increase in the talo-first metatarsal angle and an increase in the divergence of the talus and calcaneus on the AP view. The lateral view will demonstrate plantarflexion of the talus, a decrease in the lateral talocalcaneal angle and collapse of the longitudinal arch. As the deformity progresses, the subtalar and talonavicular joints narrow. Ankle radiographs show arthritis and talar tilt in a longstanding deformity.3
After clinically and radiographically evaluating the patient with a flatfoot deformity, it is important to distinguish between a flexible and rigid deformity. One can do this by evaluating the range of motion of the subtalar joint and perform the Hubscher maneuver (“Jack’s test”). If the arch cannot be recreated and the subtalar joint motion is limited, one must suspect a tarsal coalition or rigid flatfoot.
After determining whether the flatfoot deformity is rigid or flexible, the clinician should further evaluate the flexible flatfoot to determine the level of involvement of the posterior tibial tendon (PTT). The PTT is often the culprit of flexible adult flatfoot. The tendon is located posterior to the axis of the tibiotalar joint and medial to the axis of the subtalar joint. It functions to plantarflex and invert the foot.4-6
The PTT also creates a rigid lever during gait. When it is not functioning properly, the tendon is unable to form the rigid lever needed for gait and the forward propulsion of the gastroc-soleus complex acts at the midfoot, thus causing midfoot collapse.7,8 The PTT is injured by a combination of vascular insufficiency and the mechanical pulley of the tendon along the medial malleolus.
A Primer On PTTD Classifications
Johnson and Strom developed a PTTD classification system, which was later modified by Myerson to include stage IV.9,10
Stage I. Peritendinitis and tenosynovitis of the posterior tibial tendon present. The rearfoot remains mobile and the patient has pain medially. A single heel rise test reveals mild weakness to the posterior tibial tendon.
Stage II. The posterior tibial tendon is elongated and attenuated. The rearfoot remains mobile. However, the calcaneus is in valgus on stance. There is still pain medially. The patient is still able to perform the single heel rise test although it is weak. A positive “too many toes” sign is present.
Stage III. Degeneration of the posterior tibial tendon is evident. The rearfoot becomes fixed and less flexible, and the calcaneus remains in valgus on stance. The patient may have pain both medially and laterally due to impingement laterally. A positive “too many toes” sign is visible.
Stage IV. A valgus tilt to the talus in the ankle mortise and early degeneration of the ankle joint are present.
Conti and colleagues developed another common classification system.11 This classification system is based on MRI and evaluates the state of the posterior tibial tendon.
Type I tear. One or two fine longitudinal splits occur in the tendon without degeneration of the tendon.
Type II tears. This involves wider, longitudinal tendon splits and intramural degeneration. The tendon also may show a variable diameter on selected cuts where a bulbous section may be distal to an attenuated portion.
Type III tears. More diffuse swelling and uniform degeneration of the tendon are present. A few tendon strands may remain or the tendon may be replaced entirely with scar tissue.
Current Concepts In Conservative Treatment
Goals for conservative treatment of flexible flatfoot include eliminating clinical symptoms, improvement of rearfoot alignment and prevention of progressive deformity.1
Treatment for flexible flatfoot generally begins with immobilization via a removable cast boot or below the knee cast for up to six to eight weeks. This decreases inflammation and prevents overuse for acute tenosynovitis. Steroid injection into the tendon sheath for tenosynovitis continues to be controversial due to the adverse effect of tendon rupture.1
One may also utilize UCBL orthotics to stabilize the rearfoot. These are helpful in patients with a stage II deformity because the rearfoot is flexible and passively correctable in this stage. These orthotics limit the range of motion of the subtalar joint and forefoot abduction. Other orthotics may have a medial posting, like the Blake inverted orthotic, to decrease the strain on the posterior tibial tendon medially and push the foot into a more rectus position.1
Changes in shoegear and shoegear modifications are often beneficial to patients with a flexible flatfoot deformity. An extra depth shoe is able to provide a long rigid medial counter, a soft leather upper, high toe boxes and soft soles to absorb some ground reactive forces during gait. One can add a medial stabilizer to the shoe as well as a rocker bottom to assist in toe off. It is also possible to add a medial wedge inside the shoe to support the posterior tibial tendon.12
The Baldwin Boot Brace (Bolt Systems) is able to provide edema control, stability of affected joints and soft tissue protection. This low-profile device controls and restricts subtalar joint motion. This boot is able to provide good control of tibial rotational forces and has anterior padding to protect the anterior lower leg. One can use the Baldwin Boot Brace for patients with stage III deformity and patients with a fixed deformity as it holds the deformity and protects soft tissues.12
A temporary bracing option for posterior tibial tendon tenosynovitis is a stirrup brace. This brace is not able to control motion in the sagittal plane but it is able to help unload the posterior tibial tendon by transferring plantarflexion to the Achilles tendon and relieves strain from plantarflexion from the posterior tibial tendon.13
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.
Dr. DeHeer is a Fellow of the American College of Foot and Ankle Surgeons, and is a Diplomate of the American Board of Podiatric Surgery. He is also a team podiatrist for the Indiana Pacers and the Indiana Fever. Dr. DeHeer is in private practice with various offices in Indianapolis.
Dr. Taulman is a first-year resident at Westview Hospital in Indianapolis.
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