Relationship between radiologic morphology of the bone lengthening formation and its complications.

The objective was to study the different types of lengthened bone regeneration and their development during the various phases of the process to correlate them with patient factors and the surgical technique used, and to establish a possible relation between the development of the bone lengthening formation and the problems or complications. The authors studied the radiographs of a random group of 55 patients taken at three points during the course of treatment. The callus was classified with regard to its transverse diameter and the presence or absence of hypodense areas. The overall callus type was significantly influenced by the etiology, the osteotomy site, and the percentage lengthened. The percentage by which the limb was lengthened at the beginning of the process influences the overall morphology of the callus. Poor callus had been lengthened the most, atrophic callus the least. There was a correlation between the morphology of the overall callus at the end of treatment and the percentage lengthened, and between the percentage lengthened and the presence of bands at the end of treatment. The authors also found a significant correlation between age and the appearance of bands at the end of distraction. A central band was found among younger patients. The type of osteotomy affected the overall callus at the end of distraction and at the end of treatment and also influenced the transverse diameter. All the elongations with poor bone formation at the end of treatment were found to have undergone a diaphyseal osteotomy. The most common complication at the first follow-up and at the end of distraction was angulation. The diameter of the callus and the presence of bands at the end of treatment were significantly related to the complications. Fracture occurred in the first 2 weeks after removal of the external fixator in 88% of cases and in the third and fourth week in the rest. However, the segment had no significant influence on the appearance of complications. Lengthened callus with incomplete trabecular formations and hypodense areas at the end of the treatment has a high risk of fracture at the end of treatment. Callus with axial deviation, hypodense areas, or an insufficient transverse diameter during the lengthening procedure must be manipulated so that it reaches the maturing phase in better condition.