螺旋CT在青少年复发性髌骨半脱位诊断中的临床价值

目的探讨螺旋CT在青少年复发性髌骨半脱位(RSP)诊断中的临床价值。方法对37例临床诊断为青少年RSP的48个膝关节行屈膝0°和30°股四头肌紧张状态下的螺旋CT扫描,并行最大密度投影(MIP)、三维重建(3D),总结分析其影像表现,然后用屈膝0°的C T横断面图像叠加法测量外侧髌骨角(LPTA)、髌骨倾斜角(PTA),和谐角(CA)、股骨滑车角(FTA)、胫骨结节-髁间凹间距(TT-TG)5个参数。结果在48个膝关节中,股骨髁发育不良37个,髌骨形态wibergⅢ型15个,髌骨倾斜31个,髌骨外侧移位44个,内侧移位4个,内侧支持带萎缩9个,股内侧肌不良11个。各参数测量:LPTA:-4.2±3.4°;PTA:24.5±7.6°;CA:30.2±16.3°;FTA:148.7±13.4°;TT-TG:19.6±3.4mm。结论螺旋CT扫描能有效评价髌股关节关系,MIP及3D能直观显示髌股关节的骨性不良,是临床诊断青少年复发性髌骨半脱位的重要辅助手段,能为临床治疗提供确切的影像依据。

Clinical value of spiral CT in diagnosis of recurrent subluxation of patella

Objective To investigate the clinical application value of spiral computed tomography(SCT) in diagnosis of recurrent subluxation of patella.Methods 37 cases(48 knees) clinically diagnosed as recurrent subluxation of patella(RSP) in adolescent were performed SCT scanned with quadriceps contraction and knee flexion in 00、300,and then maximum intensity projection(MIP) and three-dimension reconstruction(3D) were made.We analyzed and concluded the imaging findings,measured five parameters such as lateral patellofemoral angle(LPTA),patellar tilt angle(PTA),congruence angle(CA),femoral trochlear angle(FTA) and tibial tubercle-trochlear groove distance(TT-TG) in the superimposed CT axial image which obtained in the status with knee flexion 0°.Results(1)in all 48 RSP knees,we found 37 knees with femoral trochlear dysplasia,15 knees with patellar shape typed Ⅲ of Wiberg typing,31 knees with patellar tilt,44 knees with patella lateral dislocation,4 knees with patella medial dislocation,9 knees with medial retinaculum distrophy,11 knees with quadriceps atrophy.(2)The parameters values were as following:LPTA:-4.2±3.40,PTA:24.5±7.60,CA:30.2±16.30,FTA:148.7±13.40,TT-TG:19.6±3.4mm.Conclusion spiral CT scan can effectively evaluate the relation of patellofemoral joint,MIP and 3D can reveal bone dysplasia of patellofemoral joint,So SCT is the important auxiliary method for the diagnosis of RSP in adolescent,it can supply the exact imaging informations for the clinical therapy.