青少年急性髌骨外侧脱位的MRI特点分析

MRI Features of Acute Lateral Patellar Dislocation in Adolescents

目的探讨青少年急性髌骨外侧脱位后损伤的MRI特点。方法对临床证实为急性髌骨外侧脱位的青少年MRI影像资料进行回顾性分析，对内侧髌股韧带（MPFL）、股内斜肌（VMO）、髌骨内侧缘和股骨外侧髁骨挫伤及关节软骨损伤、关节腔积液等伴随损伤情况进行评估、分析。结果共46例青少年急性髌骨外侧脱位病例纳入研究范围（年龄9—17岁，平均14．5岁）。MPFL损伤发生率为95．7％（44／46），其中部分撕裂、完全撕裂发生率分别为56．5％（26／46）、39．1％（18／46），股骨侧、髌骨侧、体部撕裂发生率分别为30．4％（14／46）、76．1％（35／46）和23．9％（11／46），MPFL多发部位损伤发生率为30．4％（14／46）。VMO损伤发生率为54．3％（25／46），Ⅰ度损伤、Ⅱ度损伤发生率分别为37％（17／46）、17．4％（8／46）。髌骨内侧缘和股骨外侧髁典型部位骨挫伤发生率为93．5％（43／46）。髌骨内侧缘关节软骨损伤发生率为89．1％（41／46），单纯关节软骨骨折、骨软骨骨折发生率分别为37％（17／46）、52．2％（24／46），股骨外侧髁关节软骨损伤发生率为47．8％（22／46），单纯关节软骨骨折、骨软骨骨折发生率分别为28．3％（13／46）、19．6％（9／46）。关节腔积液发生率为100％。结论MPFL损伤、VMO损伤、髌骨内侧缘和股骨外侧髁骨挫伤以及关节软骨损伤、关节腔积液是青少年急性髌骨外侧脱位后的常见损伤；VMO损伤均为Ⅰ度或Ⅱ度损伤。青少年MPFL损伤以髌骨侧多见，其次为股骨侧，MPFL多发部位损伤常见；髌骨内侧缘和股骨外侧髁关节软骨损伤高发，尤其是骨软骨骨折。

Objective To evaluate MRI features of injuries after acute lateral patellar dislocation in adolescents. Methods MR images of acute lateral patellar dislocation in adolescents were retrospectively analyzed. Medial patellofemoral ligament（ MPFL）, vastus medialis obliquus （VMO）, bone contusion, articular cartilage lesions and joint effusion of the patellofemoral joint were assessed. Results A total of 46 patients（ age range 9 - 17 years, average 14.5 years ） were identified. The prevalence rate of MPFL injury was 95.7% （44/46）, including 56.5% （26/46） of partial MPFL rupture and 39. 1% （18/46） of complete MPFL rupture. MPFL injury was present at femoral attachment in 30.4% patients, 76.1% at patellar attachment, 23.9% at midsubstance. MPFL injury at more than one location was present in 30.4% of patients. The prevalence rate of VMO injury was 54.3% （25/46）, including 37% （17/46） of I° - injury and 17.4% （8/46） of II°injury. The prevalence rate of bone contusion in medial patella and lateral femoral condyle was 93.5 % （43/46）. The prevalence rate of articular cartilage lesion of medial patella was 89.1% （41/46）, including 37% （17/46） of chondral lesion and 52.2% （24/46） of osteochondral lesion. The prevalence rate of articular cartilage lesion of lateral femoral condyle was 47.8% （22/46） ,including 28.3% （13/46） of chondral lesion and 19.6% （9/46） of osteochondral lesion. The prevalence rate of joint effusion was 100%. Conclusion Injury of MPFL, VMO, bone contusion and articualr cartilage lesion of medial patella and lateral femoral condyle, joint effusion are the characteristic MRI findings after acute lateral patellar dislocation,which are similar to those in adults. But MPFL is most easily injured at patellar attachment, secondly at femoral attachment, and multiple site of MPFL injury is a common injury type in adolescents. Articular cartilage lesion of medial patella and lateral femoral condyle are more common in adolescents, especially osteoehondral lesion.