A new radiographic classification scheme of congenital pseudarthrosis of the tibia

Abstract

Objective To establish a new x-ray classification scheme of congenital pseudarthrosis of the tibia (CPT) for providing rationales for its management and prognostic assessment. Methods For this retrospective study, the radiographic films of 171 CPT patients between 2004 and 2014 were analyzed. There were 125 boys (73%) and 46 girls (27%) with an average operative age of 42.5 months. The radiographic findings included the following four conditions: typeⅠwas defined by anterior bow of the tibia, cortical thickening at the apex of deformity yet marrow cavity was normal; type Ⅱ showed anterior tibial bow, cortical thickening, trabeculation defect and canal stenosis at the apex of deformity; type Ⅲ was manifested as a cystic lesion occurring in any part of tibia; type Ⅳ, pseudarthrosis of tibia. Fibula radiographic characteristics included the following four conditions: a, normal-appearing fibula; b, fibula dysplasia (diameter of fibula<diameter of normal contralateral fibula); c, fibula cystic degeneration; d, fibula pseudarthrosis. A new radiographic classification of CPT was formulated according to the radiographic features of tibia and fibula. It was independent of patient status of surgery or external/internal fixation. Results There were 171 CPT cases under the new radiographic classification scheme. The cases of each type wereⅠa (n=9), Ⅰb (n=3), Ⅰc (n=3), Ⅰd (n=4), Ⅱa (n=9), Ⅱb (n=15), Ⅱc (n=3), Ⅱd (n=6), Ⅲa (n=6), Ⅲb (n=12), Ⅲc (n=8), Ⅲd (n=17), Ⅳa (n=13), Ⅳb (n=10), Ⅳc (n=4) and Ⅳd (n=49). Conclusions The new radiologic classification scheme of CPT has considered the radiographic features of tibia and fibula. All our institutional cases are accounted for. And such a new scheme may play a key role in the diagnosis and management of postoperative complications for CPT. Further studies are warranted. Key words: Congenital pseudarthrosis of the tibia; Tibia; Fibula