OBJECTIVES

The objectives of this study were to report the radiographic follow-up of the distraction callus and to quantify its calcification process during tibial lengthening in order to achieve its calcification pattern.

MATERIALS

12 mature female beagle dogs underwent a non-simultaneous bilateral tibial lengthening by means of an unilateral device. Distraction was started five days after the osteotomy at a rate of 0.5 mm every 12 hours and prolonged during 10 days, achieving a total bone lengthening of 10 mm. After the distraction process, the distractor was kept in place until the calcification of the distraction callus was observed radiographically. Radiographs of both limbs were taken at 2-week intervals, using mammographic films, which were scanned in a normalized way. The digital images obtained were submitted to a computer software specifically designed to read grey intensities along several reading lines crossing the distraction callus and longitudinally oriented. The grid formed by the different lines spread from one cortex to the other one. The data of each line were exported as an excel file and an unique mean profile was created from all the reading lines. The "Y" axes corresponded to the intensity of grey, and the "X" axes to the reading site along the distraction callus. Mean profiles could also be obtained for the whole dogs in each phase.

RESULTS

12 mature female beagle dogs underwent a non-simultaneous bilateral tibial lengthening by means of an unilateral device. Distraction was started five days after the osteotomy at a rate of 0.5 mm every 12 hours and prolonged during 10 days, achieving a total bone lengthening of 10 mm. After the distraction process, the distractor was kept in place until the calcification of the distraction callus was observed radiographically. Radiographs of both limbs were taken at 2-week intervals, using mammographic films, which were scanned in a normalized way. The digital images obtained were submitted to a computer software specifically designed to read grey intensities along several reading lines crossing the distraction callus and longitudinally oriented. The grid formed by the different lines spread from one cortex to the other one. The data of each line were exported as an excel file and an unique mean profile was created from all the reading lines. The "Y" axes corresponded to the intensity of grey, and the "X" axes to the reading site along the distraction callus. Mean profiles could also be obtained for the whole dogs in each phase.

CONCLUSION

The results of this study suggest that the succession of graphics measuring intensities of grey is a tool that may provide objective data about calcification of the distraction callus.

In daily clinics, the calcification pattern obtained can be used as a reference to assess a proper calcification process of clinical distraction cases as well as premature detection of failures in calcification process during bone lengthening.