Quantitative evaluation of reparative osteogenesis for limb lengthening in patients with achondroplasia

The quantitative measurements of distraction regenerate bone and those of adjacent parts of maternal bone were studied by the data of computer tomography (CT) of lower limb long tubular bones in 22 patients with achondroplasia at the age of 7-23 years, who were treated in I orthopaedic department of the Federal State Science Institution - Russian Ilizarov Scientific Center «Restorative Traumatology and Orthopaedics» (FSSI RISC «RTO») within the period from 2001 till 2005. The studies were performed before hospitalization, in the process of treatment, in the immediate and long-term periods of treatment and observation. The results of the work showed, that the area of regenerate bone «growth zone» during distraction increased more than two-fold, but its percentage ratio was within 23-33 % of the total area of regenerate bone. There was a decrease of the density of maternal bone cortical plates, which on the average came to 200-300 HU in distraction period and 400-500 HU - in fixation period. The density of regenerate bone for femur and tibia by 60th day of fixation varied from 210±11 to 241±17 HU. The comparison of the measurements of cortical plate density in femur and tibia, in bone parts of contemplated osteotomy zone before treatment and the parts of the regenerate bones formed in 1 -2 years after treatment demonstrated almost complete conformity, completed roentgen-and-morphologic reorganization of bone tissue was observed, thereby pointing to proper functional ability of newly formed bone and allowing to judge the correctness of the lengthening performed.