Accuracy of complex lower-limb deformity correction with external fixation: A comparison of the Taylor Spatial Frame with the Ilizarov ring fixator

Abstract

Purpose Circular external fixators have several advantages over other surgical options in the treatment of limb length discrepancy and axial deformity. The innovative Taylor Spatial Frame (TSF) combines a rigid hexapod fixation system with the support of a webbased software program, and thus offers the possibility of simultaneous corrections of multidirectional deformities. Whilst there is still some scepticism of many Ilizarov device users about the advantages of the TSF, the purpose of the study was to perform a comparison between the TSF and the Ilizarov Ringfixator (IRF) with regard to the accuracy of deformity correction in the lower limb. Methods Two hundred and eight consecutive deformity corrections in 155 patients were retrospectively evaluated. There were 79 cases treated with the IRF and 129 cases treated with the TSF. The mean age of the patients at the time of surgery was 13.2 years (range; 2-49 years). Standing anteroposterior and lateral radiographs were evaluated preoperatively and immediately after removal of the frames. The final result was compared to the preoperatively defined aim of the deformity correction. According to the treated count of dimensions, we differentiated four types of deformity corrections. The results were graded into four groups based on the persisting axial deviation after removal of the frame. Results The aim of the deformity correction was achieved in a total of 90.7% in the TSF group, compared to 55.7% in the IRF group. On the basis of the count of dimensions, the TSF achieved obviously higher percentages of excellent results (one dimension: TSF 100%; IRF 79.3%; two dimensions: TSF 91.8%; IRF 48.6%; three dimensions: TSF 91.1%; IRF 28.6%; four dimensions: TSF 66.7%; IRF 0%). In addition, the degree of the persisting deformity increased with the number of planes of the deformity correction. Conclusions The TSF allowed for much higher precision in deformity correction compared to the IRF. In two-, three-and four-dimensional deformity corrections in particular, the TSF showed clear advantages. This may derive from the TSF-specific combination of a hexapod fixator with the support of an Internet-based software program, enabling precise simultaneous multiplanar deformity corrections.

Current concepts of leg lengthening

“…2 cm to max. 17.4 cm) for Ilizarov ring fixators (IRF) [48,57,58] and intramedullary nails [16,46,50,[59][60][61][62][63][64] and around 2.5-3 cm (min. 8 mm to max.…”

“…Only the minority of patients presents with mere leg shortening. Most also present with frontal plane deformities or, to a lesser degree, with sagittal and rotational abnormalities [48]. The deformity is graded as type I (one-dimensional) to type IV (four-dimensional), which allows for the comparison of results of lengthening and axial deformity corrections in the dependence of the complexity [48].…”

“…Based on the patient's deformity, the soft tissue data (definition of structures at risk), the desired result, the architecture (mounting, size) of the frame and the relation between origin (reference fragment, virtual hinge) and corresponding (moving fragment) points, a web-based software algorithm delivers the correction protocol and velocity with mathematic accuracy [48,130,131]. Adjustments of strut prescription usually do not necessitate return to the operating room and do not cause extra morbidity for the patient [49].…”

Сomparative study of computer-assistance ortho-suv external fixation and conventional hybrid external fixation in adolescent with genu recurvatum

“…Однако использование шарниров при коррекции деформаций является трудоемким процессом, требующим нескольких перемонти-ровок аппарата, необходимости установки шар-ниров строго на вершине деформации, несмотря на то что практически невозможно расположить сегмент конечности так, чтобы кость была стро-го в центре опоры. Опубликованные результаты работ [18,19], в которых сравнивалась точность коррекции деформаций с применением аппарата Илизарова и современных аппаратов, основанных на компьютерной навигации (гексаподы), говорят о достижении полной коррекции при примене-нии аппарата Илизарова в 26,8-79 % и более чем в 91 % случаев при применении гексаподов в за-висимости от сложности деформации. Результаты, полученные в нашем исследовании, подтверждают эти утверждения.…”

Radiographic reconstruction of lower-extremity bone fragments: a first trial

“…He invented a circular external fixator to constantly apply tension stress to the bone to stimulate its regeneration. An advancement of this system, the Taylor Spatial Frame (Smith & Nephew, Memphis, USA) enables multidirectional deformity correction [6], [7], [8]. One of the prerequisites for a successful treatment using an external fixator is the correction of the malaligned bone fragments [1].…”