After we obtained institutional review board approval, we reviewed the data of 63 patients who underwent foot deformity correction using external fixation between February 2013 and December 2017. All surgeries were performed by a fellowship-trained foot and ankle surgeon (BLB). The Inclusion criteria for this study were patients (age ≥ 17 years) with equinocavovarus deformities treated by Ilizarov technique. We excluded 18 patients who were younger than 17 years old and 17 patients with equinocavovarus deformities corrected by a one stage procedure or treated by composite external fixation. All medical records, radiographs and clinical photographs that were available were reviewed, and passive ankle range of motion (ROM) was recorded preoperatively and postoperatively by two authors (BLB, LPT).
A total of 28 patients (33 feet) participated in the study (Fig. 1). The clinical characteristics of the patients and demographic data including age, sex, affected side, body mass index (BMI),and mechanism of deformity are summarized in Table 1. There were 17 males and 11 females with a mean age of 36.52 ± 11.85 years (range, 18 to 60 years). The mean duration of deformity prior to the procedure was 17.45 ± 15.60 years (range, 1 to 50 years). The mean follow-up time was 37.30 ±10.94 months (range, 28 to 87 months). Five patients had bilateral involvement, and both feet were treated. Three patients (5 feet) had previously undergone surgical intervention related deformity correction (triple arthrodesis in 2 feet, open Achilles lengthening in 2, anterior tibialis transfer in 1). Twenty patients walked with crutches. Foot callus was present in most of the patients and skin ulceration was found in 7 patients (10 feet).
All the combinations of operative procedures performed are summarized in Table 2. The most commonly performed bone procedures were first metatarsal dorsal wedge osteotomy, which was performed in 9 feet, and subtalar arthrodesis, which was performed in 9 feet. The most commonly performed soft tissue procedures were plantar fasciotomy, which was performed in 27 feet, and Achilles tendon lengthening, which was performed in 26 feet, specifically, percutaneous Achilles tendon lengthening was performed in 20 feet, and open Achilles tendon lengthening was performed in 6 feet. Ilizarov external fixators were applied in all patients and temporary fixation of the metatarsophalangeal (MTP) joint with K-wire was performed in 12 feet.
Clinical Outcome Assessment
Clinical outcomes were assessed preoperatively and at final follow-up using the Visual Analog Scale (VAS), the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hind foot score [10], the Foot Ankle Ability Measure (FAAM) score [11], and the Short Form-36 (SF-36) questionnaire [12]. The AOFAS scoring system considers a score of ≥ 90 points as excellent, a score of 80 to 89 points as good, a score of 70 to 79 points as fair, and a score of ≤ 69 points as poor. The SF-36, a general quality-of-life assessment tool, was used to evaluate the patients’ physical function, role-physical, body pain, general health, vitality, social function, role-emotional, mental health, and health transition.
The results were evaluated based on the clinical criteria established by Ferreira et al. [13]. For the treatment of neglected clubfoot using the Ilizarov method, the criteria were as follows: a absence of pain in foot and ankle, the capacity to walk on a plantigrade foot, the capacity to wear conventional shoes, the absence of significant recurrence of the original deformity after a follow up period of at least 2 years, and patient satisfaction with the final appearance of the foot. When all the criteria were met, the result was considered good; when only one of the above criteria was not met, the result was considered fair; and when two or more of the criteria were not met, the result was considered poor. The patients’ overall satisfaction was also investigated. Patient satisfaction was determined by a questionnaire which patients were asked whether they were satisfied with the outcomes and whether they would undergo the operation again if they had the same preoperative deformities. Patients were considered satisfied when they replied they were satisfied and that they would undergo the operation again.
Radiographic Review
Radiographs are obtained to assess the bone deformity, joint incongruity, arthritis, bony spurs, deformity recurrence, and tibiotalar joint compression. The radiographic outcomes, including tibial-sole angle, tibio-talar angle, talo-calcaneal angle, talus-first metatarsal angle, and hindfoot alignment view angle, were measured using weight-bearing ankle and foot radiographs taken preoperatively and at the last follow-up visit (Fig. 2).
Statistical Analysis
The results are presented as the means and standard deviations, and 95% confidence intervals (CIs) were calculated. Paired Student’s t test was used to compare the clinical scores and radiographic angles before operation and at the last follow-up. Statistical analyses were carried out using SPSS software version 16.0 (SPSS Inc, Chicago, IL), and the level of statistical significance was set to be P < 0.05.
Operative Technique
All operations were performed under regional or general anesthesia by one surgeon (BLB). The limb was prepared and draped under all aseptic precautions. The patient was remained in a supine position and a tourniquet was applied.
We first performed a combination of soft tissue procedures, including plantar fasciotomy, abductor hallucis fasciotomy, and percutaneous/open lengthening of the tight tendon, depending on the severity and rigidity of the subcomponents of the deformities. In patients who needed tendon transfer, the tendon was transferred to the fixed position, and the tendon was fixed after external fixation was applied. Then, bone procedures, including calcaneal lateral sliding/closing wedge osteotomy, first metatarsal dorsal wedge osteotomy, tibial osteotomy, subtalar arthrodesis, and triple arthrodesis, were performed. A tibial osteotomy was performed to derotate or lengthened the limb. In general, Steinmann pins and Kirschner wires were used for fixation in the osteotomies and arthrodesis. In patients with toe plantar flexion, the corrected toes were temporally fixed with intramedullary Kirschner wires attached to the forefoot half ring for 2-3 weeks.
The Ilizarov external fixator generally consisted of two full rings around the tibia, and two half rings around calcaneus and forefoot (Fig. 3). Two rings were fixed perpendicular to the axis of the tibia by one crossed wire and two half pins for each ring. The calcaneus was fixed with crossed wire and two half pins connected to a posterior half ring. The forefoot half ring was fixed with two crossed wires. The rings and half rings were connected to each other by rods and universal hinges to allow individual movement of the distal tibia, hindfoot, and forefoot. Hinges and threaded rods were then assembled to allow the concomitant correction of forefoot adduction, midfoot cavus, hindfoot equines and varus deformities. Equinus was corrected by shortening the anterior rod between the metatarsal half ring and the tibial ring.
Postoperative Care
Correction of the deformity began immediately after the relief of pain and edema on the foot and ankle healed (after a latent period of 6 to 7 days), and doctors taught the patients how to adjust the device on their own (gradual correction at a rate of 1 mm per day). Manipulation of the Ilizarov apparatus was controlled by gradual distraction as tolerated until slight overcorrection of the deformity to 5 to 10 degrees of dorsiflexion at the ankle was achieved. Then, the patients were allowed to gradually bear weight with support on the operated limb (Fig. 4). The aim of the next phase was to consolidate the correction already achieved.
The decision to remove the fixator was made on the basis of clinical absence of tenderness, satisfactory stress tests results after the removal of connecting rods, and radiological evidence of consolidation indicating regenerate or complete fusion of the joints without joint subluxation. After the removal of the fixator, the patients used an ankle-foot orthosis continuously for 3 to 6 months, were encouraged to walk with full weight-bearing on the operated limb, and continued to perform supervised gait training and strengthening exercises to achieve the best results. Then, the patients were allowed to walk in a normal shoe. The duration of external fixation was 14.88 ± 4.53 weeks, which included the mean time required to correct the deformity, which was 4.18 ± 1.81 weeks, and the mean time of stabilization in the apparatus, which was 10.7 ± 3.17 weeks. The mean duration of hospitalization was 23.09 ± 8.43 days.