Relationship Between X Ray Classification After Union Of Congenital Pseudarthrosis Of The Tibia In Children And Postoperative Refracture

Purpose: This study aims to investigate the relationship between postoperative x ray classification after 2 years of union of congenital pseudarthrosis of the tibia(CPT) and refracture in CPT in children.Methods: A retrospective study was performed on 67 patients with Crawford type IV CPT who were treated with combined surgical technique from December 2007 to August 2012. The patients were divided into two groups, congenital pseudarthrosis of the tibia with atrophic group(group.A) and congenital pseudarthrosis of the tibia with non-atrophic group(group B), on the basis of ratio of healing cross-sectional area and transition zone in pseudarthrosis. The incidence of refracture in the two groups were investigated.Results: In group A, 5(63%) cases showed refracture; in group B, 8(14%) of the cases had refracture; the incidence of refracture in group B was lower than group A, Significant difference in refracture was found between groups A and B(P=0.005). The refracture-free cumulative survival rate drops to reach 88% at 2.1 years, 40% at 3.3 years, and 20% at 4.1 years in group A, whereas in group B, it drops to reach 94% at 4 years, 88% at 5 years, and 77% at 6.3 years after union of congenital pseudarthrosis of the tibia. In addition, the refracture-free cumulative survival rate in group B was higher than group A, the difference was significant(P<0.05). Average relative ratio of cross-sectional area in hypertrophic type 0.20(0.09, 0.44), average relative ratio of cross-sectional area in mediate type 0.18(0.05, 0.85); average relative ratio of cross-sectional area in atrophic group 0.15(0.05, 0.54). A significance difference in hypertrophic type and mediate type(P=0.024, Mann-Whitney test), hypertrophic type and atrophic type(P=0.002, Mann-Whitney test), and mediate type and atrophic type(P=0.041, Mann-Whitney test).Conclusions: After the union of congenital pseudarthrosis of the tibia in Crawford type Ⅳ patients who were treated with combined surgical technique, those with non-atrophic type(hypertrophic type, mediate type) x ray characteristic showed lower incidence of refracture than those with atrophic type. Increasing the cross-sectional area of pseudarthrosis may reduce the incidence of refracture when managing congenital pseudarthrosis of the tibia.