Taylor Kenneth F, Inoue Nozumu, Rafiee Bahman, Tis John E, McHale Kathleen A, Chao Edmund Y S
Department of Orthopaedics and Rehabilitation, Walter Reed Army Medical Center, 6900 Georgia Avenue NW, Washington, DC 20307-5001, USA.
J Orthop Res. 2006 Jan;24(1):2-10. doi: 10.1002/jor.20014.
To study the effect of applying pulsed electromagnetic fields (PEMF) during the consolidation phase of limb lengthening, a mid-tibial osteotomy was performed in 18 adult New Zealand White rabbits and an external fixator was applied anteromedially. Animals were randomly assigned to treatment and control groups. After a 7-day latency period, the tibiae were distracted 0.5 mm every 12 h for 10 days. The treatment group received a 20-day course of PEMF for 60 min daily, coinciding with initiation of the consolidation phase. The control group received sham PEMF. Radiographs were performed weekly after distraction. Animals were euthanized 3 weeks after the end of distraction. Radiographic analysis revealed no significant difference in regenerate callus area between treatment and control tibiae immediately after distraction, at 1 week, 2 weeks, or 3 weeks after distraction ( p = 0.71, 0.22, 0.44, and 0.50, respectively). There was also no significant difference in percent callus mineralization ( p = 0.96, 0.69, 0.99, and 0.99, respectively). There was no significant difference between groups with respect to structural stiffness ( p = 0.80) or maximal torque to failure ( p = 0.62). However, there was a significant positive difference in mineral apposition rate between groups during the interval 1-2 weeks post-distraction ( p < 0.05). This difference was no longer evident by the interval 2-3 weeks post-distraction. While PEMF applied during the consolidation phase of limb lengthening did not appear to have a positive effect on bone regenerate, it increased osteoblastic activity in the cortical bone adjacent to the distraction site. Since the same PEMF signal was reported to be beneficial in the rabbit distraction osteogenesis when applied during distraction phase and consolidation phase, application of PEMF in the early phase may be more effective. Further work is necessary to determine optimal timing of the PEMF stimulation during distraction osteogenesis.
为研究在肢体延长巩固期施加脉冲电磁场（PEMF）的效果，对18只成年新西兰白兔进行胫骨中段截骨术，并在前内侧应用外固定器。将动物随机分为治疗组和对照组。经过7天的潜伏期后，胫骨每12小时牵引0.5毫米，持续10天。治疗组在巩固期开始时接受为期20天的PEMF治疗，每天60分钟。对照组接受假PEMF治疗。牵引后每周进行X线片检查。牵引结束3周后对动物实施安乐死。X线片分析显示，牵引后即刻、牵引后1周、2周或3周时，治疗组和对照组胫骨再生骨痂面积无显著差异（p分别为0.71、0.22、0.44和0.50）。骨痂矿化百分比也无显著差异（p分别为0.96、0.69、0.99和0.99）。两组在结构刚度（p = 0.80）或最大破坏扭矩（p = 0.62）方面无显著差异。然而，在牵引后1 - 2周期间，两组间的矿物质沉积率存在显著正差异（p < 0.05）。在牵引后2 - 3周时，这种差异不再明显。虽然在肢体延长巩固期施加PEMF似乎对骨再生没有积极作用，但它增加了牵引部位相邻皮质骨的成骨细胞活性。由于据报道相同的PEMF信号在牵引期和巩固期应用时对兔牵张成骨有益，因此在早期应用PEMF可能更有效。有必要进一步开展工作以确定牵张成骨过程中PEMF刺激的最佳时机。
