Experimental rationale of combined distraction osteosynthesisusing an internal plate and the Ilizarov fixator

Introduction The decrease in the external osteosynthesis index during limb lengthening is a relevant problem to solve by the current orthopaedics, especially in regard to children. Intramedullary rods in pediatric orthopaedics are contraindicated due to open growth plates. The use of intramedullary wires reduces the period with the fixator on the patient’s limb but the index of osteosynthesis remains rather high. Purpose To analyze the results of the combined use of the Ilizarov fixator and an internal plate of an original design for experimental tibial lengthening. Material and Methods Leg lengthening was performed in 6 experimental dogs using the Ilizarov fixator and plating. The procedure of segmental lengthening by 14-16 % from the initial length was performed in the manual mode with the rate of 1 mm per day produced with 4 steps. Results The planned amount of lengthening was achieved in all the animals. The use of plating enabled to remove the fixator on the day of distraction completion. The index of external osteosynthesis was 12.7±0.7 day/cm. The regenerated bone was of normoplastic type. It acquired a homogenous structure after 30 days of fixation in the majority of cases. As for the complications, the resorption round one of the screws that fixed the plate was observed along with soft tissue inflammation but it did not affect the experiment results. Conclusion The combined use of plating and the Ilizarov fixator decreased the external osteosynthesis index and prevented the complications related to regenerated bone fracture or deformity after the fixator removal.