Abstract：Objective: To discuss the application value of X-ray and ultrasound in the evaluation of limb lengthening. Methods: An osteotomy was done on the tibia in 10 rabbits. After a 7-day latency period, distraction was commenced at a rate of 1mm daily. Lengthening was continued to a 30% increase over initial bone length and then left to consolidate for 5 weeks. At the osteotomy site the new callus formation and the blood circulation was monitored by X-ray and ultrasound. Results: X-ray: When the the limb was lengthened to 10%, there was obvious distraction occurred without any evidence of new bone formation within the distraction sites. When lengthened to 30%, much more callus at the lengthening area and the cortical bone appeared at both ends. Mineralized 3 weeks later, medullary cavity appeared. Ultrasound: In the early stage, the amount of the micrangium and blood flow increased and then decreased gradually. After 1 week, some speckled echogenic at the distraction site could be seen. When the limb lengthened to 30%, ultrasound can rarely penetrate the distraction gap. Conclusion: Traditional plain radiography and ultrasonography have their respective advantage and disadvantage. Evaluation of the newly formed bone with combination of the two methods is the cornerstone for terminating the limb lengthening successfully.
2011, Vol. 22 
