Roundtable Insights On Adult-Acquired Flatfoot

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Assessing The Impact Of Equinus In Treating AAF

Q: What role does equinus play in AAF?

A: All of the panelists agree that equinus plays a significant role in the pathogenesis and progression of the deformity. Dr. Yu encourages careful examination of the contralateral extremity as it will help one determine whether the equinus is secondary or a primary contributing factor to AAF.

When clinical and radiographic evaluation confirms limited ankle joint dorsiflexion secondary to a tight gastrocsoleal complex, Dr. Grossman says one should proceed to perform appropriate treatment for an equinus contracture.

Equinus contracture breaks down the midtarsal joint and medial longitudinal arch, according to Dr. Rush. He also points out that equinus has a detrimental effect on the stabilizing effect of the posterior tibial tendon and peroneus longus on the medial longitudinal arch.

“The dampening of these important dynamic stabilizers leads to the talonavicular and naviculocuneiform faults one sees with progression of flatfoot deformity,” explains Dr. Rush.

When addressing equinus with conservative therapy, Dr. Catanzariti says one should emphasize posterior muscle group stretching.

Q: How should equinus be addressed surgically?

A: For those undergoing surgical treatment, the majority of the panelists agree that one should incorporate some form of posterior muscle group lengthening into the surgical plan.

“It has been well established that correcting the equinus with some type of posterior muscle group lengthening is crucial to establishing proper correction and alignment of the hindfoot,” points out Dr. Lee.

All of the panelists say they perform either a gastrocnemius recession or a tendo-Achilles (TAL) lengthening based on the clinical findings. Drs. Lee and Yu prefer gastrocnemius recession over the TAL procedure, citing faster rehabilitation and strength postoperatively without the risk or concerns of post-op Achilles tendon rupture. When it comes to the gastrocnemius recession, Dr. Catanzariti uses a 3 to 4 cm incision along the lower leg and Dr. Grossman opts for a Strayer-type procedure.

Dr. Rush prefers to perform the gastroc recession deep to the medial head of the gastrocnemius muscle belly from a medial approach. He says the sural nerve is protected at this level and it is a true muscle recession.

“There is little chance of overlengthening and the muscle heals very quickly and completely,” notes Dr. Rush.

If a TAL is indicated, Dr. Rush says a percutaneous lengthening is easier to perform and results in less weakness. Dr. Grossman concurs, noting that he performs a percutaneous three-step TAL. Dr. Catanzariti opts for a three incision, hemisection technique for Achilles tendon lengthening.

The percutaneous, three-incision approach does offer the advantages of performing the surgery with the patient supine whereas one typically performs gastroc recessions with the patient in a prone position, according to Dr. Yu.

Here is a view of an adult-acquired flatfoot secondary to PTTD. Note the collapse of the medial longitudinal arch, valgus heel, midfoot abduction with the positive too many toes sign and valgus rotation of the hallux. (Photo courtesy of Gerard V. Yu, DPM)
Alan Catanzariti, DPM, says long leg axial views allow one to evaluate the calcaneus, subtalar joint, ankle joint and tibia relative to one another. (Photo courtesy of Alan Catanzariti, DPM)
Alan Catanzariti, DPM, says Saltzman views allow one to evaluate the calcaneus, subtalar joint, ankle joint and tibia relative to one another. (Photo courtesy of Alan Catanzariti, DPM)
Here is a lateral X-ray of an adult-acquired flatfoot with severe end-stage pronation of the subtalar joint and MTJ. Note the severe overlap of the tarsal and metatarsal bones as well as severe peritalar subluxation. (Photo courtesy of Gerard V. Yu, DPM)
This neutral position X-ray view of the same patient shows flexibility of the subtalar joint and MTJ with complete restoration of normal joint congruity and alignment. (Photo courtesy of Gerard V. Yu, DPM)
When it comes to late stage 1 AAF, Dr. Catanzariti will consider posterior calcaneal displacement osteotomies and sometimes uses this approach for early stage 2 conditions. The above photo shows a transcortical osteotomy through the posterior calcaneal tu
Here one can see shifting of the osteotomy fragment medially.
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Author(s): 
Moderator: Robert Mendicino, DPM Panelists: Alan Catanzariti, DPM, Jordan Grossman, DPM, Michael S. Lee, DPM, Shannon Rush, DPM and Gerard V. Yu, DPM

   Adult-acquired flatfoot (AAF) is one of the more common conditions that podiatrists see in practice. With this in mind, some of the leading experts on this subject shared their views and experience on this subject. They discuss the role of diagnostic imaging, their use of conservative treatments and their perspectives on appropriate surgical procedures. Without further delay, here is what they had to say.

   Q: What ancillary studies are required for proper diagnosis and treatment selection for the adult-acquired flatfoot?

   A: Michael S. Lee, DPM, says AAF is generally a clinical diagnosis. Other than the physical exam, Shannon Rush, DPM, says a proper radiographic evaluation is the most important aspect of diagnosing AAF and arriving at an appropriate course of treatment. Dr. Rush emphasizes the inclusion of foot and ankle views as well as hindfoot alignment and long leg calcaneal views.

   All the panelists agree that neutral position X-rays are helpful in determining the degree of the deformity and what procedure one should perform. Alan Catanzariti, DPM, says it is important to evaluate the talus-first metatarsal angle on both AP and lateral radiographs. He adds that the AP views also enable one to see the amount of talar head that is covered by the navicular. Standard radiographs also allow clinicians to assess the tritarsal complex for degenerative changes, according to Dr. Catanzariti. He says these degenerative changes may indicate an arthrodesis procedure as opposed to performing reconstructive osteotomies or soft tissue procedures.

   The majority of the panelists recommend obtaining ankle X-rays in order to detect valgus deformity within the ankle. When there is valgus deformity within the ankle joint, Dr. Catanzariti will typically consider performing a medial displacement osteotomy of the calcaneus.

    “This helps decrease the tension within the deltoid ligament and prevent further attenuation of medial soft tissue structures,” explains Dr. Catanzariti.

   In cases of end-stage flatfoot deformity, Jordan Grossman, DPM, says AP ankle views are useful in evaluating for deltoid ligament insufficiency and valgus deformity of the talus within the ankle mortise.

   Gerard V. Yu, DPM, and Dr. Catanzariti agree with Dr. Rush about the value of obtaining long leg axial films. Dr. Catanzariti says long leg axial views and Saltzman views allow one to evaluate the calcaneus, subtalar joint, ankle joint and tibia relative to one another. He adds that these views often facilitate appropriate procedure selection.

   Lower-extremity alignment views may also be indicated in certain instances, according to Dr. Rush. Dr. Grossman concurs, noting that obtaining Cobey and hindfoot alignment views are useful in severe cases and with lower-extremity deformity.

   When it comes to magnetic resonance imaging (MRI), Dr. Rush says he “rarely, if ever” uses it in his workup for AAF. Dr. Catanzariti agrees. However, if he is contemplating arthrodesis versus reconstruction, Dr. Catanzariti will sometimes obtain a MRI in order to detect early degenerative changes within the subtalar joint that are subtle on standard X-rays. Dr. Grossman concurs, noting that MRI is indicated in “select circumstances” in which the diagnosis is unclear.

   Dr. Lee says one may employ MRI or ultrasound imaging to evaluate the posterior tibial tendon for attenuation or complete rupture. Dr. Yu emphasizes that MRI is most helpful when clinicians use a facility that has an experienced musculoskeletal radiologist, who is knowledgeable about the clinical entity and its primary and secondary manifestations.

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