前十字韧带重建术骨隧道区的骨密度测量

 目的 比较前十字韧带（anterior cruciate ligament，ACL）重建术股骨侧与胫骨侧骨隧道区域的骨密度，为选择界面螺钉大小提供参考。方 法 招募30名年龄18~35岁的健康志愿者，用双能X线吸收（Dual-energy X-ray absorptiometry，DEXA）骨密度仪进行右下肢股骨侧与胫骨侧骨隧道区域骨密度 测量；以CT薄层扫描右侧膝关节，利用三维立体成像技术分别确定经过骨隧道中心轴的股骨与胫骨隧道截面并测量灰度值。2010年8至10月ACL撕裂确诊患者9例 ，在重建手术过程中完整取出股骨侧与胫骨侧骨隧道内松质骨柱，应用阿基米德原理测量体积骨密度。结果 DEXA测量股骨侧隧道区域骨密度为（1.162±0.034 ） g/cm2，胫骨侧为（0.814±0.038） g/cm2，两者差异有统计学意义（t=9.11，P=0.000）；骨隧道区域CT股骨侧灰度值为（211.7±11.5） Hu，胫骨侧为 （104.9±7.4） Hu，两者差异有统计学意义（t=10.15，P=0.000）；股骨侧骨柱体积骨密度为（2.80±0.88） g/cm3，胫骨侧骨柱为（1.88±0.59） g/cm3， 两者差异有统计学意义（t=4.32，P=0.002）。结论 ACL重建术股骨侧隧道松质骨密度大于胫骨侧。

Measurement of the bone mineral density in the tunnel region during the anterior cruciate ligament reconstruction

Objective To compare the bone mineral density of the regions of femoral and tibial tunnels for anterior cruciate ligament (ACL) reconstruction in order to provide reference for the choice of optimal screw diameter for interference fixation. Methods Thirty healthy volunteers aged from 18 to 35 years were enrolled in our study, and the dual-energy X-ray absorptiometry (DEXA) was used to measure the bone mineral density of femoral and tibial tunnel regions of the right knee. All the right knees of the volunteers were also scanned by spiral CT and three-dimensional reconstruction technique was utilized to determine the circular sections that pass through the longitudinal axis of the femoral and tibial tunnels separately. The CT gray scale values of the sections were measured. From August to October 2010, 9 patients who had been diagnosed as ACL rupture underwent the operation of ACL reconstruction, and cylindrical cancellous bone peg was removed from the femoral and tibial tunnel respectively during the operation. Volumetric bone mineral density of the bone pegs were measured by using a standardized immersion technique according to Archimedes' principle. Results Measured by DEXA, bone density of the femoral tunnel region and tibial tunnel region were (1.162?0.034) g/cm2 and (0.814?0.038) g/cm2 respectively. The difference was significant between the femoral and tibial tunnel region (t=9.11, P=0.000). The CT gray scale value of the section for femoral tunnel region was (211.7?11.5) Hu, while that of the tibial tunnel region was (104.9?7.4) Hu. There was statistically significant difference between them (t=10.15, P=0.000). The volumetric bone mineral density of the bone peg from femoral tunnel and tibial tunnel were (2.80?0.88) g/cm3 and (1.88?0.59) g/cm3 respectively. The difference was statistically significant (t=4.32, P=0.002). Conclusion For ACL reconstruction, bone mineral density of femoral tunnel region is higher than that of the tibial tunnel.