计算机导航技术辅助后交叉韧带重建中胫骨隧道的规划及定位

背景:常规后交叉韧带重建术可改善关节的后向稳定性,但移植物与胫骨隧道口之间相互磨损,使移植物机械强度下降或隧道口扩大而导致后交叉韧带术后残存松弛.目的:利用基于术中透视的计算机导航技术,辅助关节镜下后交叉韧带重建手术中胫骨隧道的合理规划及准确定位,探讨导航技术在后交义韧带重建手术中的有效性与实用性.设计、时间及地点:病例分析,于2006-08/2007-03北京积水潭医院完成.对象:后交叉韧带重建手术患者15例均为复合韧带损伤.14例选用异体跟腱移植,1例选用自体骨髌韧带中1/3一骨移植.方法:导航系统需要在胫骨及后交叉韧带胫骨导向器上分别安装追踪器,经过注册及校准后,导航系统识别并捕获上述追踪器主动发射的信号,实时计算确定胫骨近端的三维空间位置及与胫骨导向器的相对关系,并将后交叉韧带重建中所需要的虚拟胫骨隧道路径叠加至由术中"℃"型臂X射线透视机所获得的胫骨近端X射线影像上.根据规划方案术中实时调整虚拟隧道的位置,正位影像隧道出几位于两侧髁间嵴中线偏外侧、关节面远侧1.5cm处,侧位影像上要求在保证胫骨近端后侧皮质完整的情况下、与胫骨平台关节线角度呈最大.主要观察指标:手术中透视时间和次数,术后标准正、侧位X射线片、三维CT及MRI评估胫骨隧道的出口位置、移植物与隧道的角度、隧道与胫骨后方皮质的贴合程度及隧道后壁的完整性.结果:15例患者中14例获得手术成功,1例失败.手术中透视次数由2～15次减少至2～4次,透视时间缩短10～30 min.无导航相关并发症出现.14例获得成功的病例隧道出几均位于后交义韧带的解剖附丽区内,胫骨隧道与移植物夹角平均为123.3°;隧道与胫骨后办皮质贴合紧密,贴合距离均存2 min内.10例隧道后壁完整,4例轻度破裂但隧道整体完整性存在.结论:透视导航技术可辅助后交叉韧带重建术中胫骨隧道的快速定位,获得准确的隧道口位置和控制合理的隧道角度,具有节省透视时间、准确性高的特点.

Computerized navigation technique aided tibial tunnel localization in arthroscopic posterior cruciate ligament reconstruction

BACKGROUND:Routine posterior cruciate ligament(PCL)reconstruction can improve posterior stability of the knee joint.But the wear between graft and outlet of tibial tunnel always reduces graft mechanical strength or enlarges tunnel,resulting residual laxity.OBJECTIVE:To explore the clinical application of fluoroscopy-based navigation technique for assisting tibiai tunnel placement in arthroscopic PCL reconstruction and to investigate the efficacy and feasibility of the technique.DESIGN,TIME AND SETTING:Case analysis was performed at Beijing Jishuitan Hospital between August 2006 and March 2007.PARTICIPANTS:of 15 eases with compound ligament injury,14 underwent allograft,and 1 underwent autograft bone-1/3 of patellar tendon-bone.METHODS:The navigation system consisted of tibia tracker fixed into the proximal tibia and tool tracker attachcd with PCL tibial drill guide.With registration and calibration,the navigation system identi fied and captured the infrared signals actively from the two trackers.The computer calculated the 3D-position of the knee joint relative to the PCL tibial drill guide and then the virtue tibial tunnel was imposed into the interactive images formed by the intraoperative C-aim images.The virtue tunnel was precisely adjusted according to the intraoperative planning protocol until the ideal position achieved.In the standard anteroposterior view,the centre of the outlet of tunnel should be in the midpoint between the medial and lateral eminence and 1.5 cm from the articular surface.In sagittal plane,with the intact posterior wall,the tibial tunnel should be as close as to the posterior proximal tibial cortex to get a maximum angulation.MAIN OUTCOME MEASURES:Fluoroscopy time and times,postoperative standard anterior and lateral X-ray,outlet of tibial tunnel,angle between graft and tunnel,attachment of tunnel to posterior cortex,and integrity of posterior wall.RESULTS:Among 15 patients,14 succeeded without navigation related complications and 1 failed.The frequency of intraoperative fluoroscopy reduced from 2-10 times to 2-4 times and the exposure time for fluoroscopy shortened 10-30minutes.The tibial outlet in all success cases was located within the tibialinsertion area of posterior cruciate ligament.The average angulation between the tibial tunnel and the graft was 123.3°;all cases showed close spatial relationship between tunnel and posterior proximal tibial cortex within 2 mm,with intact posterior wall in 10 cases and slightly broken in 4 cases.CONCLUSION:With high accuracy and time-saving features,fluoroscopy-based navigation system is a feasible technique in assisting tibial tunnel placement in arthroscopic PCL reconstruction surgery.