Key Insights On Surgical Correction Of Pediatric And Adult Flatfoot

      The correction of flatfoot deformity has been an evolving and somewhat troublesome treatment in the realm of foot and ankle ailments. The treatment has differed in children versus adults and has gained extended popularity as simpler procedures have become available. The problem with simple procedures is they do not always treat the full complex of the underlying deformity.       Accordingly, let us take a closer look at the treatment of flatfoot in children and adolescents. We will consider the underlying deformity, its causes and treatment options. I will also provide my treatment preferences and reasoning for each type of treatment. In a subsequent article, we will deal with adult-acquired flatfoot and its treatment options. As I noted, the treatment of adult versus pediatric flatfoot differs greatly and one should consider each case as a different animal.       Biomechanically speaking, the pediatric flatfoot is due to one of several causes. One should initially differentiate between a rigid flatfoot and a flexible flatfoot. In cases of rigid flatfoot, the clinician must consider a tarsal coalition and you may also see a fracture with joint impingement in rare cases of rigid flatfoot.       In flexible cases, one must consider the main cause of deformity. Is the problem due to a tight or lax tendon? Is the problem due to a foot deformity? Is the problem a combination of issues? With a flexible deformity, I will often talk to my patient and the parent about the mechanics of a tripod. The foot is essentially a tripod and unless all three planes of the tripod are aligned in a stable position in relation to each other, there will be instability.       In most pediatric flatfoot cases, a combination of causes leads to the ailment. The most common and problematic cause of pediatric flatfoot is a tightness of the gastrocnemius tendon and, to a lesser degree, the Achilles tendon. Due to the lack of possible ankle dorsiflexion, there is a pronation of the foot with pain along the medial ankle and arch. A second common cause of problems is a short lateral column. In rare cases, one may note a valgus heel position in addition to or instead of a short lateral column.       The final and most commonly overlooked aspect of pediatric flatfoot deformities is the laxity of the medial column and elevated position of the first ray. There is a great deal of controversy as to the location of the actual laxity. Some believe the laxity is at the naviculocuneiform joint while others believe it to be at the first metatarsocuneiform joint.       I believe either joint can be the culprit but the more common finding in my hands has been an elevated or lax first ray. A forefoot varus deformity is a common finding and the podiatrists must differentiate this from a laxity of the first ray. A forefoot varus is a more difficult problem and more rare problem due to a complete varus of the entire forefoot. In contrast, a first ray laxity and elevatus is a single ray problem and does not involve the entire forefoot.

Helpful Diagnostic Pearls

      The physical exam begins with a gait analysis of the patient. Observe the patient walking in both posterior and anterior positions. Pay attention to the foot in static stance and compare it to walking gait. Be sure to differentiate between a valgus heel and a midtarsal abduction. Direct your attention to the tightness of the Achilles complex and midfoot pronation during late gait due to the equinus deformity. Then check the foot in a non-weightbearing exam. Check flexibility. In the rigid foot, make a diagnosis of the rigid joint and check equinus. In the flexible foot, individually check the laxity of the heel, the midfoot and the forefoot-first ray complex.       Podiatrists should correct each plane separately in order to see the correction potential and the potential for an increased compensatory deformity with each plane correction. First, correct the valgus heel alignment. In most cases, correction of the valgus heel will result in excellent hindfoot to ankle alignment but will increase the forefoot deformity. In contrast, correction of the hindfoot valgus in combination with midtarsal abduction through a midtarsal realignment without varus correction of the heel will not increase forefoot varus. This concept is critical to consider in pediatric flatfoot correction.       If there is a hindfoot valgus, the cause of the valgus may be due to an abduction of the midtarsal joint or a true hindfoot valgus. If the midtarsal joint is very abducted, an opening wedge calcaneal osteotomy (Evans calcaneal osteotomy) will correct the calcaneal valgus and midtarsal abduction without increasing the forefoot varus deformity. However, if the surgeon does a valgus correction via a subtalar arthroereisis procedure, he or she can correct the hindfoot valgus and may also correct midtarsal abduction. However, there is a problem with an increased forefoot varus that one must deal with in order to avoid a malalignment of the tripod phenomenon.

Key Considerations In Pediatric Flatfoot Correction

      At our facility, our main goal with any flatfoot correction is to recreate a stable tripod and decrease the abnormal strain on that tripod. Our most common procedures are gastrocnemius recession to decrease equinus as well as repair with possible augmentation of the posterior tibial tendon via flexor tendon transfer and first metatarsocuneiform fusion procedures.       We have found that these procedures are often essential to the correction and long-term stabilization of flatfoot deformities. Our reasoning behind a first metatarsocuneiform fusion procedure is that it allows for correction of both a hallux valgus deformity and metatarsus primus varus. It also allows for better stability of the medial midfoot and forefoot.       Our rearfoot correction procedures differ according to the needs of the patient. We have tried every type of procedure on every age and have come to some standard conclusions that may be helpful.       In pediatric cases, we will often use an Evans calcaneal osteotomy as our main procedure of choice. In certain cases, when there is minimal forefoot deformity, we will perform a gastrocnemius recession and subtalar arthroereisis procedure to allow for early weightbearing and more rapid healing. If a midfoot stabilization is necessary or there is a need for bony forefoot realignment, we will proceed with an Evans procedure. In the young adult population, we often use a calcaneal slide procedure or Evans procedure. We have not found much problem with the Evans procedure in the young adult population but a calcaneocuboid block distraction is also a good option.       In severe cases of hindfoot deformity with multiplane deformity, we will perform a double calcaneal osteotomy with a posterior tubercule medial slide and Evans procedure simultaneously. We will rarely use subtalar arthroereisis as a procedure of choice as we have found patients too often feel the implant and are not as satisfied. Forefoot correction is often necessary as is gastrocnemius recession or Achilles lengthening. If there is a posterior tibial tear, we also perform repair with possible tendon transfer augmentation.       In the middle-aged, 50-plus group, our procedure choice is far less varied. If there is minimal deformity but posterior tibial pain with minimal tearing, we often perform a gastrocnemius recession and subtalar arthroereisis. If there is an arch collapse with severe posterior tibial tear, we will often perform a posterior tibial repair and tendon transfer, a gastrocnemius recession and a calcaneocuboid block distraction arthroereisis. We have found it essential to stabilize the forefoot in middle-aged and elderly patients, and have been very happy with first metatarsocuneiform fusions. If the level of deformity is less abduction of the midfoot and more calcaneal valgus, we will substitute a calcaneal slide correction instead of a calcaneocuboid fusion.       It is rare for us to use a fusion of the talonavicular or subtalar joints as a first-line treatment unless the patient is overweight, has arthritis or has a very severe deformity. In most cases of talonavicular or subtalar fusion, one should explain to patients that there will be a fair amount of limitation to their high-level exercise habits and they will also have some limitations with abnormal terrain.

In Conclusion

      As in most foot and ankle surgical situations, one has to pay the price to have a better long-term outcome. The use of rapid healing, subtalar arthroereisis procedures has limitations unless patient selection and adjunct procedure selection are perfect.       With hindfoot correction of both valgus and adductus at the same time, there is often an increase in forefoot varus that one must deal with in order to have a stable plantigrade foot. If the surgeon only corrects the hindfoot, there is often a midfoot strain and continued collapse due to the abnormal forefoot medial arch position. It is critical to correct the forefoot alignment at the same time as one performs hindfoot correction in cases of symptomatic flatfoot.       Finally, tendon repair with possible augmentation tendon transfer and lengthening of tight posterior compartment muscle groups will aid in the decrease of foot pressure and lead to a better long-term correction.       Dr. Baravarian is the Co-Director of the Foot and Ankle Institute of Santa Monica. He is an Associate Professor at UCLA Medical Center and is the Chief of Podiatric Surgery at Santa Monica/UCLA Medical Center. Dr. Baravarian may be reached at bbaravarian@mednet.ucla.edu.