Keys To Conservative Care For Adult-Acquired Flatfoot

Author(s): 
Karolina S. Varnay, DPM, and Alan Ng, DPM

Given the common nature of adult-acquired flatfoot, these authors offer a closer look at the use of popular orthoses and braces in managing the various stages of flatfoot secondary to posterior tibial tendon dysfunction.

   A wide assortment of conservative treatment options exists for the treatment of adult-acquired flatfoot (AAF). Unfortunately, there is little research to support the use of one device over another. For many podiatrists, surgical treatment has become the mainstay of treatment for advanced posterior tibial tendon dysfunction (PTTD).

   Even so, conservative treatment still has its place and is indicated for those patients who refuse surgery (possibly due to socioeconomic issues) or those who are not good surgical candidates due to medical comorbidities. Accordingly, let us take a closer look at a few of the more popular and well-known modalities including the University of California Biomechanics Laboratory (UCBL) orthotic, custom ankle foot orthoses (AFOs) such as the Richie Brace and Arizona Brace, and the patellar tendon bearing (PTB) brace.

   Choosing the appropriate device is dependent on one’s understanding of AAF and the most common underlying causal process PTTD.

   Posterior tibial tendon dysfunction plays a crucial role in the development of pathologic flatfoot deformity in most cases. When the posterior tibial tendon is unable to lock the midtarsal joint in midstance, the stability of the midtarsal joint remains compromised during heel off. This places excessive pressures on the plantar ligamentous, muscular and tendinous structures. This leads to attenuation of these structures and collapse of the medial longitudinal arch.

   There are many underlying causes of PTTD. These may include diabetes, trauma to the tendon, diminished tendon vascularity, systemic arthritidies or simply age-related degeneration of collagen fibers.1,2

   Complete and accurate evaluation of the entire patient is necessary prior to choosing the treatment plan. When it comes to the treatment plan for a patient with AAF secondary to PTTD, one must consider the stage of the deformity, specifically the flexibility of the deformity and the presence of any associated degenerative changes. Physicians also need to take into account the underlying cause of the deformity and the patient’s medical comorbidities.

   Although many have attempted to create new classifications for PTTD, the best known and most commonly used is the system developed by Johnson and Strom in 1989 and subsequently modified by Myerson in 1996.3,4 Accordingly, the following suggested treatment options are based on the progression of deformity within this staging system.

A Guide To Treatment For Stage I PTTD

   In the first stage, acute tendonitis/tenosynovitis is associated clinically with swelling and pain upon palpation of the posterior tibial tendon, both along the distal course of the tendon and at its insertion onto the navicular tuberosity. The onset may be acute or insidious, and the patient may complain of fatigue with activity.

   Research has shown that the use of orthotics in these patients can help in the selective activation of the posterior tibial tendon. Accordingly, the orthotics reduce stress on other tendons of the foot, which are frequently recruited in compensation and over-activated in cases of PTTD, leading to symptoms of fatigue.5

   Often when one evaluates a patient with early stage PTTD, the patient will be able to perform a single limb heel rise and no observable deformity of the foot will be appreciable.

   The ultimate goals of treatment in this stage are early recognition and protection to prevent tendon degeneration and subsequent deformity. In addition, early treatment can allow resolution of symptoms and a return to a high level of activity.

   Treatment may begin with cast immobilization with either a below-knee walking or non-walking fiberglass cast, or a removable walking cast for three to four weeks or until symptoms resolve. One drawback to the use of a cast is the development of disuse muscle atrophy, which can occur after a 10-day period of cast immobilization. One may combine immobilization with rest, ice and oral anti-inflammatory medications.

   Following a period of recovery, the patient may initiate physical therapy. The efficacy of physical therapy in actually strengthening the tendon and preventing future episodes is debatable. However, a recent paper by Alvarez suggests good results with the use of adjunctive physical therapy.6

   The study enrolled 47 participants with either stage I or II PTTD in a structured rehabilitation program in an effort to strengthen the posterior tibial tendon, treat the symptoms of PTTD and prevent relapse. Participants entered the program after their symptoms had been present for an average of 135 days. They underwent an intensive rehabilitation program, which included isokinetic exercises, an exercise band, heel rises and toe walking for an average of 10 visits, including a daily home exercise routine. In addition, patients used either a UCBL orthotic or a short articulated ankle foot orthosis.

   At a minimum one-year follow-up, 83 percent of patients had resolution of symptoms and were able to avoid surgical intervention. The authors concluded that patients with stage I and II PTTD respond favorably to a structured rehabilitation program.6

When The UCBL Device Can Have An Impact

   Both over-the-counter and functional orthotics may play a role in the treatment of stage I PTTD. However, when one desires more control of the rearfoot, orthotics such as the UCBL device may prevent future exacerbations.

   The UCBL device is designed for flexible hindfoot and forefoot disorders. The device is made of made of a rigid material such as polypropylene and has a deep heel cup in order to control excessive rearfoot eversion. The success of the device lies in its ability to exert a lateral force on the calcaneus and provide support to the medial longitudinal arch.7

   Imhauser and colleagues used six fresh-frozen cadaveric limbs to evaluate the efficacy of the UCBL against the molded ankle foot orthosis, the Arizona brace and two prefabricated ankle braces in their ability to provide stability to the calcaneus and medial longitudinal arch in a flatfoot model.8 They found that the UCBL device was the most successful in stabilizing the hindfoot and medial longitudinal arch whereas the AFOs and ankle braces were only partially able to restore the parameters of a pre-flatfoot configuration. The authors concluded that the UCBL provided superior restoration of the medial arch and hindfoot in comparison to the other modalities.

   Bear in mind that obese patients may not tolerate the UCBL device. For this subset of patients, one may want to choose an AFO and line it with PPT and plastazote.9

What You Should Know About Stage II PTTD Treatment

   Continued tenosynovitis with the development of a flexible deformity is the hallmark of stage II PTTD. The heel will be in valgus and the forefoot will be in varus and abducted. Patients may be concerned that their foot has changed shape over the preceding months. They may be unable to perform a single limb heel rise.

   The goals are to correct the deformity and prevent its progression and arthrosis of associated joints. In addition, alleviating symptoms and allowing patients to function in their day-to-day activities is of major concern. It is in this stage that surgical treatment comes into play and one can consider various soft tissue and reconstructive procedures.

   Once again, the UCBL orthotic as well as other functional orthotics may be appropriate. They are less bulky in comparison to an AFO and one may still use them if the deformity is in the earlier stages. When the deformity is significant or additional stability is desirable, an AFO is a more appropriate choice. An AFO works by using the leg as an anchor to prevent excessive eversion of the hindfoot.10

   There are many AFOs with the Richie brace and the Arizona brace being two of the more common types. Ankle foot orthoses can be either solid or articulating, of different lengths and are manufactured with or without various top covers. Conventional AFOs have a calf band, double metal uprights and a hinged ankle. More recently, newer AFOs are being made of a thermoplastic mold. The thermoplastic design is significantly more lightweight, more cosmetically appealing and footwear friendly. However, the total contact nature of the thermoplastic designs may increase perspiration and friction between the device and soft tissues.

   The Richie brace, developed by Doug Richie Jr., DPM, has a functional foot orthosis that is attached to two independent struts. The struts are then harnessed together with two circumferential straps that wrap around the distal tibia.

   The Arizona brace is the brainchild of Ernesto Castro, CPed. First introduced in 1988, the brace has increased in popularity due to its low-profile design, a more forgiving leather covering and the option of having either a Velcro or lace-up closure. The brace is made of a custom-molded polypropylene, which is covered with leather and extends proximally to just above the malleoli.

   Lin and colleagues prospectively evaluated the clinical outcomes of 21 patients with early stage PTTD who wore the Arizona brace for a minimum of three months (with a range between three to 19 months).11

   Researchers evaluated multiple parameters and achieved improvement in most parameters at the final follow-up. Specifically their AOFAS hindfoot score had increased from 37.7 before use of the brace to 76.0 after a minimum of three months of use. With 90 percent of patients showing statistically significant improvement in symptoms, the authors concluded that the Arizona brace is a viable option in the treatment of stage I or II PTTD. Shoe modifications with an offset or medial flange in the heel may also be of benefit.12

How To Handle Patients With Stage III PTTD

   A rigid deformity is not amenable to orthotic treatment. Either a fixed or hinged type of AFO is a more appropriate choice. For this patient population, the goals of treatment are protection from further joint deterioration, alleviating pain and improving function.

   Physicians should use a fixed AFO simultaneously with a rocker bottom shoe to facilitate normal stride length.13 If surgery is the desired course, one should give consideration to arthrodesis over reconstructive procedures.

Pertinent Principles In Managing Stage IV PTTD

   In the final stage of flatfoot progression, valgus angulation of the talus within the ankle mortise will predispose patients to ankle arthrosis. It may be associated with lateral impingement of soft tissues between the calcaneus and the fibula. In this group of patients, a solid AFO is most appropriate as it prevents dorsiflexion and thus prevents calcaneofibular impingement.

   When one desires even more offloading, use a PTB brace. Patellar tendon bearing braces work by transferring the weightbearing forces off the foot and more proximally onto the patella and calf region. The PTB brace is very effective in axially offloading the limb and may reduce force transmitted into the foot by as much as 30 to 70 percent.12 With challenging patients, such as those patients with neuropathy, a PTB brace would be most appropriate in preventing breakdown of soft tissues.

   Researchers have even postulated that PTB braces may be helpful in preventing or reducing the risk of developing Charcot neuroarthropathy in this patient population.14 Once again, arthrodesis over reconstructive procedures is preferable in this group of patients because of the significant amount of degenerative changes present in the involved joints.

Final Words

   Often when it comes to treating AAFD, a thorough evaluation of the patient (including medical comorbidities) and his or her socioeconomic status may direct one to choose conservative care over surgical treatment. Once one decides to pursue conservative treatment, a general understanding of the progression of the deformity is necessary prior to choosing the appropriate orthotic device.

   The suggested orthotic devices are just a few of the many available for the treatment of PTTD and the suggested treatment approaches are meant to serve as a guideline based on the progression of the disease process.

Dr. Varnay is a first-year resident with the P/SL Highlands Podiatric Residency Program in Denver, CO.

Dr. Ng is in private practice at Advanced Orthopedic and Sports Medicine Specialists, P.C. in Denver, CO. He is a Fellow of the American College of Foot and Ankle Surgeons.

For further reading, see “A Guide To Conservative Care For Adult-Acquired Flatfoot” in the June 2007 issue of Podiatry Today.

To access the archives or get reprint information, visit www.podiatrytoday.com.




References:

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3. Johnson KA, et al. Tibialis posterior tendon dysfunction. Clin Orthop 1989; 239:197-206.
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Additional References
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17. Kitaoka HB, et al. Effect of foot orthoses on 3-D kinematics of flatfoot: a cadaveric study. Arch Phys Med Rehabil 2002; 83(6):876-9.
18. Mereday C, et al. Evaluation of the University of California Biomechanics Laboratory shoe insert in “flexible” pes planus. Clin Orthop Rel Res 1972; 82:45-58.
19. Root ML, et al. Normal and abnormal function of the foot. Clinical Biomechanics Corporation, Los Angeles, 1997.
20. Sferra JJ, et al. Nonoperative treatment of posterior tibial tendon pathology. Foot Ankle Clin 1997; 2(2):261-73.
21. Weinraub GM, et al. Adult flatfoot/posterior tibial tendon dysfunction: classification and treatment. Clin Podiatr Med Surg 2002; 19(3):345-70.
22. Krause F, et al. Shell brace for stage II posterior tibial tendon insufficiency. Foot Ankle Int 2008; 29(11):1095-1100.

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