The impact of selected biological factors on bone regeneration in distraction osteogenesis

Background. Comparatively few reports have analyzed the biological factors influencing the course of distraction osteogenesis, such as the etiology and magnitude of shortening or the patient's age at surgery. The aim of our study was to assess the impact of selected biological factors on the course of bone regeneration in distraction osteogenesis of the lower leg. Material and method. We examined 126 patients, on whom 138 lower leg lengthening operations were performed. Congenital shortening was the most numerous cause (54.9%), followed by postinfectious (16.6%), posttraumatic (14.3%), neurogenic (7.9%), and achondroplastic (6.3%). The course of distraction osteogenesis was analyzed on the basis of duration of treatment, expressed by the lengthening index. Results. The highest lengthening index values were found in neurogenic patients, somewhat lower in congenital. The lowest lengthening index values were observed in postinfectious and posttraumatic shortenings, and in the group of bi-level lengthenings in achondroplastic patients. The lengthening index decreased along with increasing elongation. Lower lengthening index values were found in patients younger than 20 years, regardless of the method and number of osteotomy levels. Conclusions. There is clinical evidence for the impact of etiology, age, and magnitude of shortening on the course of distraction osteogenesis. The shortest treatment duration was found in shortening of acquired etiology and achondroplasia, and in patients older than 20 years. The values of the lengthening index were the lowest in lengthenings over 6 cm, whereas the greatest values were observed in lengthenings less than 4 cm.