[Intramedullary Elastic Transphyseal Tibial Osteosynthesis and Its Effect on Segmental Growth].

BACKGROUND

Intramedullary transphyseal elastic osteosynthesis is used in children for the diseases accompanied by the reduced strength properties of bone tissue, and primarily for osteogenesis imperfecta.

OBJECTIVE

The purpose of the experimental study was to investigate tibial growth under the conditions of transphyseal counter-directed insertion of elastic rods without bone integrity breaking, under transverse fracture modeling, as well as under combining transphyseal reinforcement and subperiosteal positioning the titanium mesh with the elastic rods intervolved in it.

METHODS

Non-randomized controlled trial was performed. Three series of experiments performed in 18 puppies. Counter-directed transphyseal reinforcement of tibia performed in Series I, transphyseal reinforcement combined with transverse osteotomy of leg bones--in Series II, transphyseal elastic osteosynthesis and subperiosteal positioning the titanium nickelide mesh with intervolved in it elastic rods during transverse leg bone osteotomy performed in Series III.

RESULTS

Transphyseal reinforcement resulted in growth retardation of the operated tibia. The loss of residual growth was 3.8 mm (p=0.078) in series I; 7.8 mm (p=0.032)--in series II; 7.7 mm (p=0.042)--in series III. Eccentric insertion of transphyseal rods formed an angular deformity (mean value 7°; p=0.023) of the distal tibial epiphysis in the process of residual growth. Periosteal and endosteal reactions contributed to enlargement of diaphyseal diameter of 3.9 mm (series II; p=0.037) and 3.8 mm (series III; p=0.041). Any difference of diameter between operated and intact tibia was not observed in series I.

CONCLUSION

Intramedullary transphyseal reinforcement retards longitudinal bone growth. The positioning of the telescopic systems should be as close as possible to the center of growth plates in order to prevent angular deformities. Subperiosteal reinforcement doesn't retard consolidation of fragments, and it can be combined with intramedullary transnhyseal osteosynthesis.