自体与同种异体骨-髌腱-骨重建前交叉韧带术后胫骨骨隧道演变过程的MRI对比研究

目的利用MRI比较自体与同种异体骨-髌腱-骨(bone-patellar tendon-bone,B-PT-B)重建前交叉韧带(anterior cruciate ligament,ACL)术后胫骨骨隧道的变化过程.方法将50例B-PT-B重建ACL患者,分成A、B两组,A组为自体组20例,B组为同种异体组30例.分别于术后1、6周、3～4、5～6、7～8、9～10、12～13、15～16、18～19、21～22个月进行磁共振(magnetic resonance image,MRI)检查,采用胫骨骨隧道斜轴状位扫描技术,扫描序列包括:T1WI、T2WI、GE-T1WI、GE-STIR.动态观察骨隧道内的MRI信号变化,并比较术后6周、3～4、5～6个月骨隧道扩大情况.结果术后6周骨隧道扩大增幅最为显著(P＜0.05).术后3个时间段上比较两组骨隧道扩大程度均无显著性差异(P＞0.05).MRI动态观察发现,A组术后5～8个月,移植物与骨隧道之间已发生骨性愈合;而B组将延迟到术后7～13个月.结论MRI是准确评价骨隧道的一种无创手段;同种异体B-PT-B在胫骨骨隧道内的愈合相对延迟;自体组与同种异体组术后胫骨骨隧道扩大的程度基本相当.

A comparative MRI analysis of tibial tunnel after anterior cruciate ligament reconstruction with bone-patellar-bone from autograft and allograft

Objective To evaluate the tibial tunnel following anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone from autografts or allografts by MRI. Methods Fifty patients who underwent ACL reconstruction were divided into group A (n=20) and group B (n=30). MRI examinations were performed on each patient periodically after surgery at 0.2T with spin echo T1 weighted, T2 weighted, gradient echo T1 weighted and gradient echo STIR oblique axial images. Cross-sectional area (CSA) perpendicular to the long axis of the tibial tunnel was calculated digitally at three levels. Results The percentage of the tibial tunnel enlargement was significantly higher within the first 6 weeks after surgery (P<0.05), yet there existed no significant difference between group A and group B at 6 weeks, 3 to 4 months and 5 to 6 months after surgery. Bone plug healing, with disappearance of the low-signal-intensity interface between the graft and osseous tunnel had achieved by 5 to 8 months after surgery in group A and 7 to 13 months in group B. Conclusion MRI evaluation using digital direct CSA measurement provided a highly accurate and harmless method for tibial tunnel assessment. MRI analysis showed there was a slower healing process in the tibial tunnel of allograft group, yet there existed no significant difference of tibial tunnel enlargement between autograft group and allograft group.