This retrospective study was approved by the institutional review board. Informed consent was obtained from all patients. Twenty-eight patients (47 feet) with symptomatic flexible flatfoot deformities underwent reconstructive surgery from July 2014 to October 2017. There were 16 boys (26 feet) and 12 girls (21 feet) with an average age of 11.7 ±2.1 (range 9-14) years at the time of surgery.
Patients with symptomatic, flexible, idiopathic flatfoot were included in this retrospective study. The exclusion criteria were neuromuscular disease, tarsal coalition, traumatic flatfoot, congenital vertical talus, and over-correction of cavus foot. Patients underwent conservative methods involving the use of orthotics and ankle brace as well as physical therapy at a minimum of 12 months before operation. If the pain still persisted, the surgery was recommended.
The detailed history and physical assessment were taken before the surgery. Flexible flatfoot is characterized by a flat arch during weight bearing, but the arch recovers when the individual is sitting with the foot dangling. It was important to note the appearance of the forefoot when the heel was reduced to a neutral position during the examination. The Silfverskiold test was used to identify the contracture of the gastrocnemius-solues complex or Achilles tendon. The dorsiflexion of <10º indicated contracture of the Achilles tendon, regardless of whether the knee was flexed or extended. If the dorsiflexion was >10º with knee flexed but <10º with knee extended, it implied contracture of the gastrocnemius complex. The Coleman block test or heel rise test was used to assess the hindfoot flexibility. The “too-many-toes” sign could show the extent of forefoot abduction.
Radiographic evaluation should include weight-bearing AP and lateral views of the foot, ankle AP view, and hindfoot alignment view. Advanced imaging is rarely indicated for the assessment of flatfoot deformity. Computed tomography (CT) and magnetic resonance imaging (MRI) were usually employed to identify the extent and exact location of the coalition and soft tissue changes, respectively. The talonavicular coverage angle (TNCA) and talar–first metatarsal angle (T1MT) were assessed on foot AP views. The calcaneal pitch angle and Meary’s angle were recorded on foot lateral views. The calcaneus valgus angle (CVA) was assessed on hindfoot Saltzman views.
The patients with a thigh tourniquet were placed in the supine position on operation table under general anesthesia in addition to the regional nerve block. First, we performed gastrocnemius recession or percutaneous Achilles lengthening according to the preoperative Silfverskiold test. Then, an incision is made below the tip of the fibula along with the peroneal tendon. The sural nerve should be protected. After the subperiosteal dissection, a 45º osteotomy was performed with an oscillating saw. The posterior aspect of the calcaneus was translated medially at approximately 0.5-1.0cm to realign the hindfoot. The K-wire was used to fix the fragment temporarily. We raised the lower limb and evaluated the heel alignment under direct vision. It was exactly determined with an intraoperative Saltzman view. The MDCO was fixed with two 4.0-mm cannulated screws. If the epiphysis was open, a contoured mini-plate or K-wire was used for fixation (Fig. 1a).
Following the MDCO procedure, midfoot abduction was evaluated clinically. Then, we extended the incision over the calcaneocuboid joint for the LCL procedure. The osteotomy cut was made 1 cm posterior to the calcaneocuboid joint. With the osteotomy distracted, the position of the talus relative to the navicular is checked clinically and radiographically. Once the position is corrected, the allograft with an appropriate size was used to maintain the reduction. Fixation was performed with K-wire, cannulated screw or plate (Fig. 1f).
After completing the hindfoot osteotomy, medial soft tissue reconstruction was performed. A medial incision was made over the posterior tibial tendon (PTT). We debrided and repaired the mild or moderate PTT tear. If the PTT presented a large, extensive and degenerative lesion, repair and flexor digitorum longus (FDL) transfer were adopted. FDL was harvested from the Henry's knot and passed from the plantar to dorsal direction through a drill hole and sutured to itself in mild inversion. The deltoid and spring ligaments were evaluated. Imbrication suturing before FDL transfer was performed with appropriate tension. In children with a painful accessory navicular bone, which was more prevalent among this age group, we always tried to use screw for fixation of the accessory bone, if the bone fragment was large enough. The excision of the entire accessory navicular bone and reattachment with the suture anchor were necessary if the bone was small (Fig. 1b-d).
At the completion of the soft tissue procedures, Cotton osteotomy was performed with residual forefoot supination . An incision was made over the medial cuneiform. Then, a laminar spreader was inserted, and a structural allograft was wedged into the osteotomy site after evaluation with intraoperative fluoroscopy. The plate was used to fix the osteotomy (Fig. 1e).
The sutures were removed at 14 days postoperatively. A short cast was used, and weight bearing was avoided in the first 6 postoperative weeks. During this period, patients were advised to undergo physical therapy for rehabilitation and to reduce the risk of deep vein thrombosis. Thereafter, the patients were allowed partial weight bearing as tolerated. At 8 weeks postoperatively, X-ray examination was performed to assess the consolidation of the osteotomies. The patients were allowed to perform full weight bearing after achieving complete bone healing. Outpatient visits at 6 months and 1 year postoperatively were required. The hardware was removed at 1 year postoperatively. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot (100 point scale) scores and Foot and Ankle Outcome Score (FAOS) (100 point scale) were employed to evaluate the clinical outcome. The FAOS consists of 5 separate subscales: pain, symptoms, activities of daily living, sports activities and quality of life. These were each scored separately on a scale from 0 (poor outcome) to 100 (best outcome) . Radiographic parameters included TNCA, T1MT, calcaneal pitch angle, Meary’s angle, and CVA. All data were assessed preoperatively and at the final follow-up visit.All of the included parameters on the weight-bearing views were underwent by two observers independently.
Statistical analysis was performed using SPSS (version 23.0; SPSS Inc, IBM company, Chicago, IL, USA), and Significance was set at p < 0.05. The data was demonstrated as the mean and standard deviation. Differences between preoperative and postoperative functional and radiologic outcome were analyzed using paired Student’s t test.