Experimental Approval of Combined Fixation for Femur Lengthening
Elimination of congenital shortening of lower limb still remains a complex and unsolved orthopaedic task which requires an improved fixation technique as well as adjusted tactics of treatment and rehabilitation procedures. Purpose of the study - experimental approval of femur lengthening technique by external fixation with Ilizarov apparatus and internal fixation by plate. Materials and methods. Femur lengthening was performed in 6 mongrel dogs. Average animal age was 1,5±0,3 years, average weight - 20±5 kg, femur length - 22±2 sm. External apparatus with two supports and a titanium plate of an original design were applied under general anesthesia on the right femur of animals. Lengthening was performed manually at a rate of 1 mm per day in 4 stages at a distance of 10% from initial segment length. External apparatus was removed on the last day of distraction after locking the plate. Xray examination was done on the day of surgery, in 7, 14 and 25 days from the onset of distraction as well as in 14, 30, 60 and 90 days after completion of distraction and removal of external apparatus. Three animals were taken out of experiment in 30 days of fixation, remaining three animals - in 90 days. After euthanasia the authors performed autopsy of the organic femur complex and tissues contacting the plate. Results. The use of operated limb was not restricted during the whole distraction period. The authors observed first roentgenological signs of distraction osteogenesis on 7th day of lengthening. By the end of distraction period, at 25th day, shadows of regenerates demonstrated longitudinal striated structures in all cases. Median lucency area of 1-5 mm was located diagonally and across the regenerate or was intermittent. In 60 days of fixation Xrays demonstrated homogeneous regenerate. External fixation index was 13,9±1,5 days/sm ( p ≤0,05). The authors observed no cases of implants fracture or deformity during the experiment. Conclusion. Application of the developed plate in combination with external apparatus demonstrated high efficiency for femur lengthening in experiment study.