Inclusion criteria:1) Patients’ age≥18 years or skeletal mature; 2) CFD combined with LLD; 3) The deformities were complex and rigid;4) Dimeglio scores≥6; 5)LLRS AIM scores≥3
Exclusion criteria:1) Lost follow-up; 2) Incomplete medical records
According to the criteria above, 32 patients (21 males,11 females) who had CFD combined with LLD were selected into our study. Its duration ranged from 3 to 43 years (mean was 13.7 years). All the patients were older than 18 years (age ranged from 18 to 58 years, with a mean of 33.6).
Thirteen out of 32 patients were students, eight were workers, two was employees, two was doctors, and seven patients had no job.
The aetiologic factors were poliomyelitis (10 patients), congenital talipes equinovarus (CTEV) (6 patients), osteomyelitis (2 patients), burn contractures (2 patients), traumatic injuries (4 patients) and neglected, relapsed clubfoot ( 6 patients) or tethered cord syndrome(TCS) (2 patients).
The patient's demographics were shown in Table 1.
Table 1
|
|
n %
|
Range
|
Mean
|
Total
|
|
Age
|
|
|
18–58
|
33.6
|
32
|
|
Sex
|
|
|
|
|
32
|
|
|
Male
|
21 66%
|
|
|
|
|
|
Female
|
11 34%
|
|
|
|
|
Laterality
|
|
|
|
|
32
|
|
|
Left
|
14 44%
|
|
|
|
|
|
Right
Bilateral
|
16 50%
2 6%
|
|
|
|
|
Etiology
|
|
|
|
|
32
|
|
|
Poliomyelitis
|
10 31%
|
|
|
|
|
|
CTEV
|
6 19%
|
|
|
|
|
Foot Deformities
Duration
Follow up
EFT
HI
|
Osteomyelitis
Burn
Trauma
Clubfoot
TCS
Equinus
PEV
Pesplanovalgus
Cavovarus
|
2 6%
2 6%
4 13%
6 19%
2 6%
6 19%
13 41%
5 16%
8 25%
|
3–43
33–62
5.5-8.0
1.0-3.2
|
13.7
42.8
6.5
1.7
|
|
|
Abbreviations: CTEV congenital talipes equinovarus, PEV pes equinovarus, EFT external fixation time, HI healing index, TCS tethered cord syndrome |
Preoperative Examination
All patients received preoperative detailed clinical examination and imaging examination of both lower limbs, foot and ankle. (Fig.1) A thorough history and examination often establishes the cause of deformity. Clinical examination should evaluate the components of any deformity; the length of both lower limbs; the gait circle; forefoot-hindfoot relationships (eg, the Coleman block test[14], peek-a-boo sign) ; hip, knee, ankle, subtalar, midtarsal and toe joints ranges of movement; lower limb and foot muscle strength and the condition of the skin and soft tissues.
A complete radiographic evaluation is important. Weight-bearing ankle and foot radiographs including AP view, Lateral view, Long axis view of calcaneous are essential. The full-length X-ray of both lower limbs in the standing position is also needed (Fig.2). A weight-bearing AP view of the ankle and foot helps to assess the condition of the ankle and whether there is rotational deformity of foot. A weight-bearing lateral view is especially helpful. The long axes of the talus and first metatarsal create Meary’s angle. A normal measurement is 0 to 5 degrees. The Pitch angle measures the plantar aspect of the calcaneous with the weight-bearing surface. Normal measurement is around 25 degrees, and anything over 30 degrees should be considered a moderate deformity. Hibb’s angle is formed by the axis of the first metatarsal with the body of the calcaneous. Normal measurement is less than 45 degrees.[15] Long axis view of calcaneous is useful to evaluate tibia, ankle, and calcaneal deformity.[16] Normal calcaneus has a valgus angle of 0 to 5 degrees, but the line on the vertical axis of the mid-body of the calcaneus should be parallel and approximately 1 cm lateral to the mid-diaphyseal line of the tibia.[17] Full-length X-ray of both lower limbs in standing position to assess the lower limb forceline and whether there are rotation, angle, shortening deformity. The axial deformity of the tibia defined by the CORA (center of rotation angulation) method with the malalignment test. [18]The center of rotation of angulation is identified by locating the intersection of the proximal and distal tibial mechanical axes.The radiological examination of foot and ankle deformity combined with lower extremity deformity requires a high level , which must be completed by a senior radiologist and orthopedic surgeon.
Computed tomography (CT) and 3D reconstruction can help us understand the deformity more intuitively. Doppler ultrasonography helps to assess if there are vascular malformations of the lower extremities. EMG (Electromyography) to assess the presence of nerve damage in the lower extremities.
For all admitted patients, The Limb Lengthening and Reconstruction Society (LLRS) AIM score [19]and The Modified Dimeglio score[20, 21] were used for preoperative evaluation.
Operative technique
In all cases, surgery was carried out under general anesthesia without neuromuscular blockage in supine position. Systemic antibiotics were given half-hour before operation and a tourniquet was used.
Tibial and Fibular Osteotomy
After K-wire location and guide, tibial osteotomy and fibular osteotomy were to be performed using swing blade [22] If patients had angular deformity of the lower limb, the osteotomy plane was usually at the CORA point. If patient only had lower leg shortening, the tibial osteotomy plane was close to the metaphysis and the fibula osteotomy plane was distal.
Soft-tissue Release
We did the percutaneous achilles tendon lengthening for patients who with achilles tendon contracture. Tendon transfer (eg. Posterior tibial tendon transfer , Peroneus longus strengthens peroneus brevis tendon) was used in patients with imbalanced muscle strength.[4] But, tendon transfer procedure usually performed when the distraction procedure was completed.
Foot Osteotomy
Different osteotomy procedures [7, 23] were applied according to the type of deformities in order to recover plantigrade foot in one stage. The osteotomy surface was fixed by K-wires or plate. For patients with forefoot deformities, midfoot osteotomy may be preferred. For patients with first-ray decline, dorsal wedge osteotomy of the first metatarsal was needed. For patients with hindfoot varus or valgus, calcaneus osteotomy was required to correct the hindfoot force line.
Ilizarov External Frame Application
We placed the Ilizarov external frame on K-wires which were inserted in above steps. The frame consists of three main parts: the tibial base frame, the heel construct, and the forefoot construct. The tibial base frame was composed of four complete rings, the most proximal ring and two distal rings of the tibia were fixed by two crossed K-wires. The middle ring was fixed with two crossed olive wires or one K-wire and one olive wire. The osteotomy segment of tibia was fixed by a single Schanz pin and connected to the tibial base frame. The heel construct is a half ring attached to the calcaneum by one K-wires and additional two half pins. The forefoot part of the frame usually consists of a half ring attached to two crossed K-wires inserted transversely through the metatarsal shafts. All rings were connected by threaded rods. Appropriate hinges were attached between the three constructs to drive the deformity correction.
To prevent toe contracture, K-wires were inserted into all toes. (Fig.3)
C-arm fluoroscopy was used throughout the procedure to ensure ideal positioning of the fixator.
The surgical procedure was shown in Table 2.
Table 2
Osteotomy Type
|
n
|
Soft-tissue
Procedure
|
n
|
Midfoot
The first metatarsal
Calcaneus
Tibial Osteotomy
Fibular Osteotomy
Supramalleolar
|
28
16
20
32
32
5
|
PTT transfer
ATT transfer
PL transfer
Achilles tendon
lengthening
Flexor tendon
lengthening
|
14
18
32
32
10
|
Abbreviations: PTT posterior tibial tendon, ATT anterior tibial tendon, PL peroneus longus |
Postoperative Care
Correction was began after a latency period of seven to ten days [22, 24] Distraction was initiated in a rate of 1 mm/day, divided in four or six time intervals. In the period of distraction, the tension over the soft tissues, the neurovascular status, the pin site situation and presence of pain were monitored regularly. Patients were encouraged to weight-bearing with the help of a walker or crutches to stimulate osteogenesis. Radiographs were taken every two weeks to observe how the distraction was progressing. The distraction speed and plan were adjusted based on the radiographic results. The heel construct and the forefoot construct were removed after 2 months. After full correction of lower limb was achieved, the tibial frame remained stable for 6 weeks. (Fig.4) During this period of distraction, patients were encouraged to full weight bearing and improvement of the gait by walking exercise.
After defomity correction, the Ilizarov external fixation was removed (Fig.5).To maintain the correction and avoid early recurrence, an ankle–foot orthosis was routinely used in all patients for the following 6 months to 1 year.[25, 26]The foot component was removed four weeks after the surgery. Before removal, the hinge was unlocked in the daytime for range of motion exercise. At night, the hinge was locked with the ankle placed at 5-10o dorsiflexion.
During the follow-up, The Association for the Study and Application of Methods of Ilizarov (ASAMI)–Paley score was performed to evaluate bone healing and functional recovery of the limb. The Modified Dimeglio score was used to evaluate the improvement of foot deformity postoperative.
Statistical analysis
Data were expressed as means. Statistical computation of data was performed using the statistical package SPSS 22.0 (SPSS, Chicago, IL, USA). Differences between pre- and postoperation were tested by independent samples t-test and the P-value <0.05 was considered statistically significant.