Nonelongating rod placement after osteosynthesis of congenital pseudarthrosis of the tibia: should an elongating rod have been installed?

After the osteosynthesis of congenital pseudarthrosis of the tibia (CPT), an intramedullary rod is usually left behind to prevent refracture. However, whether a nonelongating rod may fulfill this goal or an elongating rod has a superior effect is not known. We investigated the outcomes of nonelongating rod installations and attempted to assess potential benefit and disadvantage of an elongating rod installation. A retrospective study was performed on 37 cases of CPT in 29 patients in which a nonelongating rod remained in situ after successful osteosynthesis. The temporal and spatial patterns of refracture after osteosynthesis were analyzed by reviewing serial radiographs and medical records. Elongating rod installation was simulated using preoperative radiographs to determine whether an additional osteotomy was necessary. The mean age of the patients at the index operation was 4.4 ± 2.2 years. Fourteen out of 37 cases sustained refractures at an average of 30.6 months postoperation (range = 7–69). Refractures occurred in areas protected by an indwelling nonelongating rod in all cases. Thirteen of 14 refractures occurred at the previous pseudarthrosis or fracture site. If an elongating rod were to be installed, an additional osteotomy would have been required in 11 out of 37 cases (29.7%) because of proximal segment angular deformity. The findings suggested no clear evidence that an elongating rod would have prevented refracture, while potentially increasing procedural complexity. Hence, the role of elongating rods in the management of CPT warrants further comparative investigation.