[Eight-Plate Guided Growth Treatment for Angular Deformities and Length Discrepancies of the Lower Limbs in Children. Our First Experience].

PURPOSE OF THE STUDY: The aim of this paper is to present our first experience with and the results of treating angular deformities and length discrepancies of the lower limbs in children and adolescents using the Eight-plate system, and to compare our results with the literature data.

MATERIAL AND METHODS: A total of 22 patients underwent surgery for the correction of angular deformities or length discrepancies of the lower limbs in 2014. Using Eight-plates, temporary medial hemiepiphysiodesis was carried out in 13 patients with the diagnosis of genu valgum (group 1). In nine patients (group 2) the Eight-plate was used to correct milder forms of leg length discrepancy by epiphysiodesis involving the distal femur only or also the proximal tibia. The Eight-plate system consists of a plate with two or more holes and two screws. Under X-ray image intensifier guidance, the plate was inserted above the physis of the long bone through a minimally invasive approach. Pre-operative long-standing radiographs of the lower extremities were measured. Post-operatively, radiographic assessments and clinical examinations were done at 3-month intervals to monitor the effects of therapy.

RESULTS: In group 1, the average pre-operative intermalleolar distance (IMD) measured on standing radiographs was 15.2 cm. The average lateral distal femoral angle (LDFA) of 82° before surgery increased to 90° and the average pre-operative medial proximal tibial angle (MPTA) of 95° decreased to 88° at the time of plate removal. In all group 1 patients the therapy was completed successfully at an average of 9.2 months. The mean values of changes recorded at 3-month intervals of followup were 2.1° (± 0.9°) for LDFA and 1.5° (± 0.6°) for MPTA. The therapy in group 2 (average leg length inequality, 2.1 cm) was finished and evaluated in seven patients; in two patients it remained to be completed. The average Eight-plate guided growth treatment was 12.7 months, and the average reduction in leg-length discrepancy recorded at 3-month intervals was 4.9 mm. There were no complications.

DISCUSSION: All our results so far obtained are in agreement with those of the authors pursuing this topic for a longer time. Compared to the currently used Blount's staples, the Eight-plate is a growth-plate sparring method which avoids damaging the growing physis and is thus suitable for use in children under 10 years of age. It is also associated with a fewer number of complications.

CONCLUSIONS: Our first results, although based on a short follow-up, clearly show that the Eight-plate guided growth method has several advantages; it is a great contribution to surgery and brings new options particularly for the correction of angular deformities in patients under 10 years.