The treatment of CPT is controversial. Most series are small, non-comparative, and composed of heterogenous groups of patients (Choi et al. 2011
Over the last few decades, intramedullary rodding with bone grafting and Ilizarov’s technique have emerged as the 2 most commonly used methods (Plawecki et al. 1990
, Paley et al. 1992
, Guidera et al. 1997
, Grill et al. 2000
, Ohnishi et al. 2005
, Mathieu et al. 2008
, Choi et al. 2011
). The Ilizarov technique, first introduced in the western world in the 1980s, has been widely used for CPT and has gained acceptance in various centers (Choi et al. 2011
). This method allows treatment of not only the pseudoarthrosis but also LLD, angular tibial abnormalities, proximal fibular migration, and foot contractures (Plawecki et al. 1990
, Guidera et al. 1997
). According to the multicenter study of the European Paediatric Orthopaedic Society (EPOS), the Ilizarov method has been found to be the gold standard for treatment of CPT (Grill et al. 2000
The Ilizarov procedure is, however, associated with a high union rate, and also with a substantial refracture rate. In his series of 16 cases of pseudoarthrosis, Paley et al. (1992)
reported on refractures in 5 patients after initial union. Inan et al. (2006)
reported on 16 patients treated with Ilizarov. All the patients united but 10 patients had late axial malalignments and refractures. Cho et al. (2008)
reported on 23 patients with atrophic type of CPT who were treated with Ilizarov’s technique. 20 of them suffered from refractures within 5 years of surgery.
The other important complication of the Ilizarov method is the late axial malalignment that may develop after radiographic union (Mathieu et al. 2008
). In one of the earliest series, Ilizarov and Gracheva (1971)
had axial malalignments in 5 of 16 patients who were treated by the method. Kristiansen et al. (2003)
also noted similar rates of residual axial deformities. Our series has shown comparable results, with substantial symptomatic malalignments in 2 of 15 patients.
The relationship between these axial malalignments and refractures and the exact cause of refracture has been studied in great detail by several authors. Young age at surgery with a low cross-sectional area of the united segment of the pseudoarthrosis, ankle valgus due to fibular non-union, and non-compliance with bracing are all thought to cause refractures (Paley et al. 1992
, Cho et al. 2008
, Choi et al. 2011
). However, we feel that there are only 3 important causes of refractures, namely (1) axial deviations leading to stress risers and fractures, (2) loss of intramedullary support after removal of nails, and (3) non-compliance with external bracing regimen. Insufficient resection of the pseudarthrotic site is in itself a poor prognostic factor, but usually the poor result is because of a non-united pseudarthosis rather than a refracture.
Thus, in our series we have added a supplemental antegrade intramedullary nail to support the bone as an internal splint. Though this nail cannot prevent the biological process of refracture, it still acts as an effective intramedullary strut to prevent further refracture. We obtained good solid union without refracture in 11 of 15 patients and only 1 patient suffered from refracture, which required refixation and additional bone grafting. This rate was similar to or better than that reported in most earlier series ().
Comparison of the present series with other series
The relationship between the fibular status and ankle malalignment has been investigated by numerous authors. Fibular union has to be looked for, and proximal migration of the fibula has to be looked for and prevented. Proximal migration of the distal fibula was seen in 7 of our patients, all of whom had undergone bone transport. In these 7 patients, we transfixed the distal tibiofibular joint, at least during the period of bone transport. We also looked for residual ankle valgus malalignments and identified 7 patients with ankle valgus. We corrected ankle valgus exceeding 5°, similarly to Inan et al. (2006)
The method of nailing has also been a matter of considerable debate in CPT. Retrograde intramedullary rodding has been used by many authors, with good results. In their long-term study of 11 patients, Shah et al. (2011)
showed union in all patients with 6 refractures occurring in 5 patients. Dobbs et al. (2005)
_ENREF_15 showed satisfactory long-term results in 16 of their 21 patients treated with transankle Williams rod stabilization, with 12 cases of refracture. However, ankle joint function and stiffness is an important drawback with this type of fixation. Shah et al. (2011)
showed no ankle joint motion in those patients in whom the rod was retained. Ankle function was satisfactory only in the 3 patients in whom the rods were stopped just above the ankle. We anticipated this problem and therefore used the antegrade method of intramedullary nailing in all patients, and found satisfactory ankle motion in most of the patients. However, the direction of nailing is relatively dependent on the location of the CPT, since extremely distal location of the pseudarthrosis, and those very near the distal tibial physis, may still require a transplantar nail; these patients are known to have poor ankle function. We could, however, obtain good results in almost all our patients with antegrade direction of the nail; complete union occurred in all but 3 of the patients. 2 of the patients had to be supplemented with a plate to achieve union while 1 of them had not achieved union at the last follow-up.
Our patients had some residual limb length discrepancy after the surgery, with a mean value of 1.9 (1–3.2) cm at the last follow-up (as compared to 2.5 (1.5–5) cm preoperatively). However, union is the most important parameter, and limb length discrepancy can be tackled later on, if necessary. Even when the Ilizarov method was used for lengthening, the initial resection was so extensive in some patients, and even after substantial lengthening, some residual shortening was present. Since most of the patients had a residual LLD of less than 2 cm, repeated distraction osteogenesis was not done in any of the patients.
The present study is quite similar to that of Mathieu et al. (2008)
, who published a series of 10 patients with CPT who were treated with a combination of intramedullary nailing and the Ilizarov technique. At a mean follow-up of 1.2–6.6 years (comparable to our series), they had good results in 9 cases, with 14 complications. There were a few notable differences. Firstly, Mathieu et al. used different kinds of nails (Elastic nails, Kirschner wires, and telescoping rods) and also different configurations (antegrade or retrograde). The other difference is that we measured the functional outcomes by the validated AOFAS score.
The present study has some limitations. It is a pilot study with very good medium-term results. Long-term studies until skeletal maturity are needed to evaluate the benefit of this method. In addition, our group was not homogenous as almost half of the patients had been operated previously, some of them several times.
In conclusion, our method combines the qualities of two techniques and appears to provide lower refracture rates, fewer axial malalignments, and comparable functional outcomes than the methods used in other series.