Department of Radiology, Oslo University Hospital, Norway.
Acta Orthop. 2010 Dec;81(6):733-6. doi: 10.3109/17453674.2010.533934. Epub 2010 Nov 11.
In clinical practice, achieved lengthening of a callotasis zone should be maintained after the external fixator has been removed. The common understanding has been that the regenerated bone may subside. To investigate this, we used high-resolution radiostereometric analysis (RSA) with accurate measurement of the lengthening zone.
We assessed the longitudinal subsidence of a callotasis zone after removal of the external fixator in distraction osteogenesis in 16 patients who underwent 17 segmental lengthening operations on the tibia (n = 9) or femur (n = 8). Median lengthening was 32 (6-80) mm. RSA was performed at the end of the consolidation period before the external fixation device was removed, and this was later repeated at a median time of 11 (4-32) weeks after frame removal.
A minimal median longitudinal change of 0.01 (-0.28 to 0.60) mm across the lengthening zone occurred in uncomplicated cases.
Our results indicate that no subsidence of clinical interest occurs after external frame removal.
在临床实践中，外固定器去除后，应当维持牵张成骨区已获得的延长。普遍的认识是，再生骨可能会下沉。为了研究这一现象，我们使用了高分辨率放射影像学分析（RSA），对延长区进行了准确的测量。
我们评估了 16 例患者的 17 次胫骨（n = 9）或股骨（n = 8）节段性延长手术中，外固定器去除后牵张成骨区的纵向下沉情况。平均延长长度为 32（6-80）mm。在去除外固定装置之前的巩固期结束时进行 RSA 检查，之后在去除框架后的中位数时间 11（4-32）周时再次进行检查。
在无并发症的情况下，延长区的最小纵向变化中位数为 0.01（-0.28 至 0.60）mm。
我们的结果表明，外固定器去除后不会发生临床上有意义的下沉。
