[Comparison of Modifications of Femoral and Tibial Lengthening in Children].

PURPOSE OF THE STUDY Limb lengthening has always belonged to the most complex surgical techniques in paediatric orthopaedics. In our study, we compared the results of femoral and tibial lengthening using three different surgical techniques. The presented study aimed to shorten the duration of external fixation to a minimum and to reduce the complication rate. MATERIAL AND METHODS The retrospective study compared 74 patients (38 boys, 36 girls) who had undergone stepwise progressive lengthening of the femur or tibia between the years 2007 and 2019. The most frequent indication was the proximal focal femoral deficiency (PFFD, 33 patients). The total number of lengthening procedures was 130 (femur 72, tibia 58), the follow-up period was 2-14 years. The following modifications of surgical techniques were used: (i) standard approach, i.e. corticotomy with a two-stage removal of the fixator, (ii) preventive fixation with elastic stable intramedullary nails (ESIN) and also with a two-stage removal of the fixator, and (iii) standard approach with an early removal of the external fixator and plate osteosynthesis. RESULTS The mean lengthening achieved was 56 ± 18 (27-114) mm in femur and 54 ± 16 (25-110) mm in tibia. There was no statistical difference in the lengthening achieved by different modifications. The mean duration of external fixation in femur and tibia lengthening was comparable (166 and 164 days). The complications were observed in 60% of lengthening procedures, the most frequent being the pin release or axial malalignment of the lengthening (33 cases, 25%). The patients with ESIN displayed statistically the lowest complication rate (26%), the highest complication rate was seen in children with osteosynthesis using a plate (80%). CONCLUSIONS It follows from our results that fixation with intramedullary nails in comparison with the standard approach and plate osteosynthesis helped decrease the number of complications by more than 50%. The plate osteosynthesis is indicated in patients with repeated lengthening (achondroplasia, hypochondroplasia or PFFD with pronounced shortening) since it significantly reduces the duration of external fixation. Key words: limb lengthening, femur, tibia, surgical techniques, complications.