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Point-Counterpoint: Is Conservative Care The Optimal Treatment Course For Adult-Acquired Flatfoot?
Yes.
Offering insights on the pathomechanics of the deformity as well as key findings from the research, this author says appropriate conservative care can help prevent progression to more advanced stages of adult-acquired flatfoot.
By Paul Scherer, DPM
Adult-acquired flatfoot (AAF) has to be one of the most frustrating foot deformities to treat, either conservatively or surgically. The difficulty and frustration probably originates with the lack of understanding of the true etiology or pathomechanics of the deformity. Sure, we know that ultimately the tibialis posterior loses sufficient strength to maintain congruity of the midtarsal joint, creating a disaster for the subtalar and ankle joints.
If we are going to discuss surgical or non-surgical treatment, we must first have a discussion on deformity versus pathology and the classification of the various stages of the deformity. Adult-acquired flatfoot is not pathology but rather a deformity. Treating the deformity without a true understanding of the underlying pathology is similar to treating the symptoms of infection rather than treating the organism that created the infection.
The progression of this entity from simple inflammation of the tendon to tendinosis through rearfoot subluxation creates various stages that one can best approach as four individual or separate entities. It is a mostly logical assumption that the earlier the stage of the deformity, the more successful non-surgical treatment is but conversely, surgical treatment may not be more successful for the later stage IV of the deformity. Staging the deformity carefully is essential to making a decision on long-term treatment, either surgical or non-surgical.
Recognizing that a multilevel and interrelated pathology is occurring is also essential for successful treatment. I personally agree with Richie’s postulation that “significant ligamentous rupture occurs” once the loss—or, a better word, exhaustion—of the posterior tibial muscle happens.1 The flattening of the longitudinal arch and the subluxation of the rearfoot occur in concert with the ultimate attenuation and destruction of the spring ligament, superficial deltoid, the plantar fascia and finally, the long and short plantar ligaments.
This combined series of unfortunate events may be the reason that surgical anastomosis of the posterior tibial tendon alone is associated with only very brief success or total failure, and rarely is effective in restoring the structural integrity of the foot.
Conservative care should address each particular stage of the deformity with a keen understanding that the objective of treatment is intended to prevent or prolong advancement to the next stage, which is ultimately inevitable.
Anyone with a modicum of understanding of the tissue stress theory knows there is a stage 0 of adult-acquired flatfoot. The patient rarely recognizes this stage and therefore the clinician rarely treats it. Often, the history reveals this “pre-stage,” consisting of and characterized by sudden and intermittent pain, swelling, inflammation and disability along the course of the tibialis posterior tendon. One must treat these signs and symptoms with the immediate aid of immobilization, compression, elevation, ice or non-steroidal anti-inflammatory drugs (NSAIDs).
What The Research Reveals
The subsequent four stages of adult-acquired flatfoot after stage 0 do not need description but I would like to review a few studies that compare outcomes, considering that each stage of the deformity requires a separate and distinct treatment plan, and evaluation of surgical or non-surgical care.
One of the most revealing papers on adult-acquired flatfoot is Imhauser and colleagues’ 2002 work on evaluating the efficacy of external stabilizers (both orthoses and braces) for conservative treatment of adult-acquired flatfoot.2 This early cadaveric work compared several external orthoses and braces, from functional polypropylene orthoses to lace-up ankle-foot orthotics (AFOs), on six specimens that were surgically altered to mimic adult-acquired flatfoot. Researchers applied body weight by using an axial loading apparatus and the foot bone motion, therefore measuring joint motion with and without each brace.
The researchers made interesting observations in relationship to the modalities that we commonly use in conservative care of adult-acquired flatfoot.2 The study authors noted “the in-shoe orthotic provides superior restoration of both arch and hindfoot kinematics. It was the only device that returned the kinematics of both the arch and hindfoot.” Now we know we can restore kinematics in a scientific setting but how effective are orthotics and braces in a clinical setting?
In 2003, Augustin documented that “although there is a role for surgical management of AAF, a well fitted custom molded leather and polypropylene orthosis can be effective at relieving symptoms, and either obviating or delaying any surgical intervention.”3 This prospective single cohort study consisted of 47 patients with Stage I, II or III adult-acquired flatfoot. Each patient wore an Arizona type brace before surgery. The study demonstrated that the brace was successful at reducing symptoms in 90 percent of the patients.
Chao and coworkers in 1996 reported that 33 of 49 patients showed improvement in pain, limp, ambulation and use of assistive devices following conservative intervention with either a sophisticated medially (varus)-posted shoe insert, or a molded leather and polypropylene AFO.4
In 2006, Alvarez and colleagues used bracing in conjunction with muscle strengthening physical therapy for Stage I and II adult-acquired flatfoot in 47 consecutive patients.5 The authors demonstrated a positive outcome that avoided surgical intervention in 83 percent of the patients.
Kulig and colleagues in 2009 performed an excellent randomized controlled study on the non-surgical management of adult-acquired flatfoot with orthoses and resistive exercise.6 The study compared, over a 12-week period, orthoses and stretching to orthoses and only stretching plus concentric, progressive resistive exercise. According to a Foot Function Index score, pain and disability decreased in both groups, but decreased much more when researchers added the resistive exercise.
Final Thoughts
This is all positive encouragement for the clinician to seriously first consider the conservative treatment of adult-acquired flatfoot, especially when we know there are limited negative side effects or complications of bracing in comparison with the disastrous results of a failed surgical intervention.
What we do not know is how to determine which factors—such as body mass, gender, working status, symptom duration pain, previous treatment with which brace and length of care—play a role in deciding when surgical or non-surgical intervention is appropriate. If this type of study happens, it will allow both the patient and doctor to make an even better long-term treatment plan.
Dr. Scherer is a Clinical Professor at the Western University of Health Sciences College of Podiatric Medicine in Pomona, Calif. He is also the CEO of ProLab Orthotics/USA.
References
1. Richie D. Orthotic treatment of the adult acquired flat foot. Podiatry Management. 2015; 10:115-22.
2. Imhauser C, Nicholas A, Abidi M, et al. Biomechanical evaluation of the efficacy of external stabilizers in the conservative treatment of acquired flat foot deformity. Foot Ankle Int. 2002; 23(8):727–37.
3. Augustin J, Lin SS, Berberian WS, Johnson JE. Nonoperative treatment of adult acquired flat foot with the Arizona Brace. Foot Ankle Clinics. 2003; 8(3):491–502.
4. Chao W, Wapner K, Berberian W, et al. Nonoperative management of posterior tibial tendon dysfunction. Foot Ankle Int. 1996; 17(12):736–41.
5. Alvarez, G, Marini, A, Schmitt, C, et al. Stage I and II posterior tibial tendon dysfunction treated by a structured nonoperative management protocol: an orthosis and exercise program. Foot Ankle Int. 2006; 27(1)2–8.
6. Kulig K, Reischi SF, Pomerantz AB, et al. Nonsurgical management of posterior tibial tendon dysfunction with orthoses and resistive exercise: A randomized controlled trial. Physical Therapy. 2009; 69(1):26–37.
For further reading, see “A Guide To Orthotic Therapy For Adult-Acquired Flatfoot” in the July 2011 issue of Podiatry Today or “Keys To Conservative Care For Adult-Acquired Flatfoot” in the August 2009 issue.
No.
While these authors concede that a trial of conservative care is prudent for stage I deformities, they say there are viable surgical options for patients with stage I and stage II adult-acquired flatfoot.
By H. John Visser, DPM, FACFAS, and Jesse Wolfe, DPM
Adult-acquired flatfoot or posterior tibial tendon dysfunction (PTTD) gained popular recognition in a classification by Johnson and Strom in 1989.1 The authors described three stages of PTTD and popularized the “too many toes sign” as a clinical diagnosis of this condition. In 1996, Myerson and colleagues added a fourth stage that noted the progression of flatfoot, including valgus ankle deformity secondary to deltoid ligament insufficiency.2
As a progressive deformity, flatfoot is a degenerative condition of the posterior tibial tendon. Secondary manifestations exist such as trauma, obesity, rheumatoid arthritis, seronegative arthritis and diabetes. Most commonly, adult-acquired flatfoot is known as a “nonspecific tenosynovitis” associated with middle-aged women.
To understand the pathomechanics of PTTD, one must understand normal biomechanical foot and ankle function. After heel contact, the tibialis posterior muscle acts as a shock absorber for the subtalar joint, which limits rearfoot eversion by eccentric contraction.3 During midstance, posterior tibial contraction causes subtalar inversion and also locks the transverse tarsal (midtarsal) joints. This results in a rigid lever for forward propulsion, allowing the gastroc-soleus complex to act through the metatarsal heads. The tibialis posterior in propulsion accelerates subtalar joint supination and assists in heel lift. Body weight shifts from lateral to medial through the longitudinal axis (talonavicular joint) during final propulsion.
With PTTD, balance weighs on the peroneals with greater rearfoot eversion and ligamentous tension and stretching of the medial structures during stance. There is decreased inversion of the subtalar joint and the rearfoot cannot function as a rigid lever. The gastroc-soleus and peroneals act at the talonavicular joint and allow increased midfoot abduction, which produces a levering action of the tarsometatarsal joints. This affects the spring and deltoid ligament complex.3
Pertinent Surgical Insights For Patients With Stage I Adult-Acquired Flatfoot
The discussion at hand is conservative versus surgical management of PTTD. There is not much of an issue with stage III (rigid) or stage IV (ankle) deformity as the consensus is that surgery on those patients is desirable. Concern and much debate occurs with stage I and II deformities.
We have considered stage I patients to be without deformity but refined classifications show damage to the posterior tibial tendon.2 Earlier intervention by “rebalancing” the foot may prevent more significant stage II deformities. Though flexible in nature, stage II deformities can lead to more advanced deformities and one may address this with more aggressive osseous and even arthrodesis procedures. Surgeons may consider a more aggressive early approach to prevent deformity progression. Certainly, a trial of conservative care is prudent.
Patients who present with a stage I flatfoot manifest in stage IA, which is tenosynovitis without deformity.4 With the failure of initial conservative care, one can consider tenosynovectomy by percutaneous decompression or tenoscopy. Removing the inflammatory source can preserve the tendon. In stage IB, the posterior tibial tendon demonstrates a partial tear but no hindfoot deformity.4 In this situation, a limited incision with repair is warranted. Depending on foot flexibility, consider anastomosis with flexor digitorum longus or peroneus brevis lengthening to offset weakening and eliminate the deforming force.
Patients who present with stage IC show a tear in the tibialis posterior tendon with early compensation and weakening demonstrated as minor heel valgus.4 Consider repair of the tendon tear with a flexor digitorum longus anastomosis, a medial displacement calcaneal osteotomy to mechanically assist a loss of tibialis posterior muscle power as well as a peroneus brevis transfer or lengthening.
A Closer Look At Surgical Options For Stage II Adult-Acquired Flatfoot
Stage II deformity implies significant posterior tibial tendon attenuation or frank rupture. Patients presenting with initial stage II adult-acquired flatfoot demonstrate heel valgus. When reducing valgus to neutral, one will see varying degrees of residual forefoot supination (supinatus).
In stage IIA-1, there are two situations to assess intraoperatively. One initially performs a medial displacement calcaneal osteotomy and flexor digitorum longus transfer into the navicular. If the forefoot reduces at ankle neutral, there is no further surgery for the forefoot. If one must plantarflex the ankle to reduce the forefoot supination, perform a gastrocnemius recession or tendo-Achilles lengthening. When the forefoot is fixed in supination (forefoot varus) after stage IIA-I procedures, adaptive changes have occurred along the frontal plane of the forefoot that are manifested as faults.
For the patient classified with stage IIA-2 adult-acquired flatfoot, the forefoot is fixed in varus and the surgeon addresses this by a Cotton opening wedge osteotomy of the medial cuneiform, a Hoke medial naviculocuneiform arthrodesis or a first metatarsal medial cuneiform arthrodesis depending on fault position (usually navicular-medial cuneiform) or joint condition.4
Another issue is the condition of the tibialis posterior tendon and whether to repair or excise it. Valderrabano and colleagues looked at magnetic resonance images (MRI) after posterior tibial tendon repair.5 They noted pre-op fatty infiltration but also acknowledged a post-op decrease in tendon degeneration and an increase in muscle size. Wacker and coworkers noted flexor digitorum longus hypertrophy postoperatively on MRI after repair of the posterior tibial tendon.6 Thus, the consensus is to repair the attenuated tendon.
Recent considerations have focused on tendon balance. As the flexor digitorum longus is only 28 percent as strong as the posterior tibial tendon and only 69 percent as strong as the opposing peroneus brevis, consider a transfer of the peroneus brevis to longus in conjunction with a flexor digitorum longus transfer. This also affects the mechanical strength of the peroneus longus at the first ray and contributes to medial column stability.
Stage IIB consists of forefoot abduction in conjunction with heel valgus.4 Forefoot abduction occurs at the midtarsal or transverse tarsal joint most commonly, or at the first tarsometatarsal joint. Abduction through the midtarsal joint manifests as talar uncoverage of the talonavicular joint. In cases of less than 40 percent uncoverage, surgical management consists of repair of the tibialis posterior tendon, a medial calcaneal displacement osteotomy, a flexor digitorum longus transfer and transfer of the peroneus brevis to the peroneus longus. If there is between 40 and 50 percent uncoverage, consider an Evans calcaneal osteotomy with bone graft. Wedge sizes are limited to 8 mm so as not to increase calcaneocuboid joint contact pressures. If residual heel valgus persists, add a medial calcaneal osteotomy.
Also, consideration of subtalar joint arthroereisis with a medializing calcaneal osteotomy is an option. The medializing calcaneal osteotomy protects the arthroereisis implant when one needs to remove it. Each includes tibialis posterior tendon repair and flexor digitorum longus transfer. When uncoverage is in this range, one must assess the spring ligament and repair is required if the ligament is torn.4 If there is over 50 percent uncoverage, consider subtalar joint and talonavicular arthrodesis or a calcaneocuboid distraction arthrodesis with bone graft. All these procedures include equinus release.
Stage IIC relates to residual medial ray instability.4 After addressing heel valgus and forefoot abduction with equinus, remaining faults may persist at the talonavicular, navicular-medial cuneiform or first metatarsal-medial cuneiform joints. Consider osteotomy or arthrodesis at individual or multiple points for fixed varus forefoot.
Lastly, when considering operative correction, one must assess the opposite foot and ankle. Although full biomechanical correction is a goal, appropriate procedure selection should restore balance.
Dr. Visser is the Director of the SSM Health DePaul Hospital Foot and Ankle Surgery Residency. He is a Fellow of the American College of Foot and Ankle Surgeons.
Dr. Wolfe is a second-year resident with the SSM Health DePaul Hospital Foot and Ankle Surgery Residency.
References
1. Johnson KA, Strom DE. Tibialis posterior dysfunction. Clin Orthop Relat Res. 1989; 239:196-206.
2. Bluman EM, Title CI, Myerson MS. Posterior tibial tendon rupture: A refined classification system. Foot Ankle Clin. 2007; 12(2):233-249.
3. Brodsky JW. Preliminary gait analysis results after posterior tibial reconstruction: a prospective study. Foot Ankle Int. 2004; 25(2):96-100.
4. Koutsogiannis E. Treatment of mobile flatfoot with displacement osteotomy of the calcaneus. J Bone Joint Surg Br. 1971; 53(1):96-100.
5. Valderrabano V, Hintermann B, Wischer T, et al. Recovery of posterior tibial muscle after late reconstruction following tendon rupture. Foot Ankle Int. 2004; 25(2):85-95.
6. Wacken J. MR morphometry of posterior tibialis muscle in adult acquired flat foot. Foot Ankle Int. 2003; 24(4):354-357.
7. Miller S. A new operative approach for flatfoot secondary to posterior tibial insufficiency: A preliminary report. Foot Ankle Int. 1997; 18(4):206-212.
For further reading, see “Current Concepts In Surgery For Adult-Acquired Flatfoot” in the October 2012 issue of Podiatry Today, “Pediatric Flatfoot: When Do You Treat It?” in the January 2012 issue or “Keys To Revising Failed Flatfoot Surgery” in the September 2014 issue.
To access the archives, visit www.podiatrytoday.com.
