Complications in Pediatric Flatfoot Reconstruction

Introduction

Flatfoot is a normal shape of the human foot from birth through old age. It is seen in most infants and approximately 20% to 25% of adolescents and adults. Flexible flatfoot (FFF) is the subtype seen in essentially all affected infants and approximately 64% of flatfooted adolescents and adults. It does not cause pain or disability. FFF with a short tendo-Achilles (FFF-STA) accounts for approximately 27% of the 23% of flatfeet in adolescents and adults. Many or most FFF-STAs are painful. Approximately 9% of the 23% of adolescents and adults with flatfoot have rigid flatfoot with limited mobility of the subtalar joint. Most rigid flatfeet are due to tarsal coalitions. Only about 24% of them are painful. So, the message is that flatfoot, whether flexible or rigid, is a common foot shape that is usually asymptomatic, not causing pain or disability.

The subtype of flatfoot that most commonly causes pain and dysfunction is FFF-STA. For these cases, efforts should be made to relieve the pain by nonoperative intervention. Firm or hard arch supports increase activity-related pain under the medial midfoot and should be avoided. If prolonged attempts to relieve activity-related axial loading pain under the medial midfoot and/or impingement-type pain in the sinus tarsi are unsuccessful, surgical reconstruction is indicated. Isolated surgical heel cord lengthening to convert FFF-STA to FFF is rarely successful because it leads to lever arm dysfunction. The heel cord lengthening must be combined with flatfoot reconstruction.

Many surgical techniques to correct flatfoot deformity have been described and reported during the last century. The most successful procedure, in short- and long-term follow-up, has been the lateral column–lengthening osteotomy, also known as the calcaneal-lengthening osteotomy (CLO). The concept was published in 1975 by Evans, but the detailed technique for flatfoot reconstruction, based on the CLO, that is used by most surgeons around the world was developed and published by Mosca in 1995.

The CLO corrects all components of valgus/eversion deformity of the hindfoot at the site of deformity. It must, however, be appreciated that it does not correct the associated segmental deformities found in a symptomatic flatfoot. All flatfeet have supination deformity of the forefoot within the calcaneo-pedal unit (CPU), that is all the bones in the foot except the talus. If structural, it is an additional deformity in the flatfoot that must be corrected concurrently using an opening or closing wedge osteotomy of the medial cuneiform. And the reason for pain in most painful flatfeet is contracture of the gastrocnemius or the entire tendo-Achilles (TA). Concurrent lengthening of a contracted gastrocnemius or TA must be performed.

This chapter will highlight ways to avoid and treat the complications of flatfoot reconstruction surgery when the surgery is based on the CLO.

Preoperative Issues

The best way to avoid the complications of flatfoot surgery is to avoid flatfoot surgery.

This starts with acquiring a full understanding of the flatfoot shape and its natural history. With that background, flatfoot surgery is performed only if strict criteria are met. The indications for flatfoot surgery are flatfoot :

• 1.

  with short heel cord (TA or gastrocnemius),

• 2.

  with activity-related weight bearing pain under the medial midfoot and/or impingement type pain in the sinus tarsi area,

• 3.

  often with exaggerated callus formation/erythema/blistering under the medial midfoot,

• 4.

  and with failure of prolonged attempts at nonoperative management to relieve the pain.

Flatfoot surgery is not cosmetic surgery. As confirmed in a Cochran Review study published in 2011, there are no data supporting the correction of the flatfoot shape in asymptomatic individuals at any age.

The remainder of this chapter highlights the complications of flatfoot surgery itself, how to avoid them, and how to manage them.

Not all flatfeet are alike. They must be differentiated to ensure that the proper operation is performed.

The normal physiologic flatfoot described in the introduction has valgus/eversion deformity of the hindfoot. This is a “rotational” hindfoot valgus deformity due to external rotation of the subtalar joint as a component of eversion. It is seen in typical idiopathic flatfoot and in acquired flatfoot in children with cerebral palsy and myelomeningocele. There is a positive/outward thigh-foot angle identified on physical examination. There is lateral positioning of the navicular on the head of the talus and a positive/outward talus–first metatarsal angle visualized on standing anteroposterior (AP) radiographs. For these, the CLO (along with associated procedures described earlier) is appropriate.

“Translational” hindfoot valgus, as seen in congenital subtalar joint synchondrosis/synostosis (fibular hemimelia, hemiatrophy) and most cases of surgically overcorrected clubfoot, is not an indication for the CLO. In these, the thigh-foot angle is typically neutral (straight ahead). The talonavicular joint is anatomically aligned, and the AP talus–first metatarsal angle is 0 degrees. For these, a posterior calcaneus medial displacement osteotomy (along with associated procedures) is indicated.

Approximately 10% of flatfooted adolescents and adults have rigid flatfoot, of which approximately 90% have a coincidental tarsal coalition. Most flexible and rigid flatfeet are asymptomatic. Surgery is indicted only for those in both groups with activity-related foot pain who fail to achieve pain relief following prolonged attempts at nonoperative management.

Preoperative evaluation must differentiate flexible from rigid flatfoot. Surgery for rigid flatfoot is algorithmic and may involve resection of the coalition alone, flatfoot deformity correction alone, or concurrent resection of the coalition and deformity correction.

Typical flatfoot reconstruction surgery is rarely successful in individuals with generalized ligament laxity, such as those with Marfan, Ehlers–Danlos, or Down syndrome.

Unfortunately, there is limited research support for any reliably successful flatfoot surgery technique(s) in these individuals.

Intraoperative Issues

In his 1975 seminal article entitled “Calcaneo-valgus deformity,” Dillwyn Evans simply wrote:

“The anterior end of the calcaneus is…divided through its narrow part in front of the peroneal tubercle by an osteotome, the line of division being parallel with and about 1.5 cm behind the calcaneo-cuboid joint. The cut surfaces of the calcaneus are then prised apart… and a graft of cortical bone taken from the tibia is inserted.” He wrote no other details about the operation. The intermediate-term surgical results in his patients, as reported by Phillips in 1983, indicate that Evans was consistently successful in achieving his goals.

Early in my career, I came to learn that many orthopedic surgeons internationally attempted to perform the procedure after reading Evans’ article and had variable, but generally poor, results. They therefore abandoned it. Intrigued by Evans’ concept, encouraged by Phillips’ report, and dissatisfied with other proposed surgical treatments for painful flatfoot deformities, I attempted to interpret what Evans meant and probably did, but did not elaborate upon. The result, published in 1995, was my treatment method for reconstruction of complex multisegmental flatfoot deformities based on correction of valgus/eversion hindfoot deformity with the CLO.

It has been shown that reliable success of flatfoot reconstruction surgery based on the CLO requires adherence to all described soft tissue and bone procedures. Shortcuts and failure to perform some or all individual associated procedures leads to inferior outcomes and avoidable complications.

Wrong Location of the Osteotomy

Evans described the location of the osteotomy as at the “being parallel with and about 1.5 cm behind the calcaneo-cuboid joint.” Based on my in vitro and in vivo observations, that places the osteotomy through the middle facet of the subtalar joint in most feet. A cadaveric research study indicated that perhaps only 54% of feet have separate anterior and middle facets. Despite that, there have been no articles, or even case reports, documenting the development of subtalar joint degenerative arthritis following calcaneal lengthening. That said, it is at least theoretically possible that arthritis could develop if the osteotomy violates the middle facet. No one stands on the anterior facet, only the middle and posterior facets. Therefore, I proposed that the osteotomy exit between the anterior and middle facets.

Additionally, it is technically easier to control the anterior calcaneal fragment at the calcaneocuboid (CC) joint if it is large. An osteotomy that exits between the anterior and middle facets and is parallel with the CC joint would create a small and unstable anterior fragment. Therefore, the osteotomy should end in the interval described but begin more posterior.

Using minifluoroscopic guidance, a small gauge guide wire in inserted in the calcaneus starting laterally at the critical angle of Gissane (which is between 2 and 2.5 cm posterior to the CC joint) and ending medially at the posterior edge of the interval between the anterior and middle facets ( Fig. 35.1 ). With soft tissue retractors surrounding the calcaneus circumferentially at this level, an oblique osteotomy is performed with a sagittal saw along the anterior surface of the guide wire.