目的探讨髌骨剥脱性骨软骨炎的MRI表现。方法 回顾性分析经临床或手术确诊的18例髌骨剥脱性骨软骨炎的MRI资料，其中5例行关节镜手术，将手术结果与MRI资料对照分析。结果  18例中，病灶均位于髌骨关节面中下部，大小约11×11×7mm，其中软骨下骨质缺损区16例，软骨下囊变4例，反应性骨髓水肿8例，骨质缺损区上面覆盖的关节软骨异常14例，关节内游离体2例，合并股骨髁发育不良者7例，髌骨高位者8例,滑膜炎者4例。在5例行关节镜手术的病例中，MRI所显示的软骨异常均为手术结果所证实。 结论 髌骨剥脱性骨软骨炎的主要MRI表现是：髌骨关节面中下部软骨下骨质缺损区及其表面覆盖的软骨信号异常。

Objective The objective was to explore the magnetic resonance manifestations of patellar osteochondritis dissecans (OCD). Methods We retrospectively analyzed MR images of 18 cases using OCD of the patella confirmed by clinical or surgery. In 5 cases, surgery was carried out, and we compared the surgical findings with the MR findings in these cases. Results In all 18 cases, OCD was located central-inferiorly on the patella, and the average size was 11×11×7mm. Subchondral deformities was present in 16 out of 18 cases, subchondral cyst formation in 4 cases, reactive bone marrow edema in 8 cases, overlying patellar cartilage abnormality in 14 cases, loose body in 2 cases, patella alta in 8 cases, hypoplastic sulcus in 7 cases, and synovitis in 4 cases. In all 5 cases in which surgery was carried out, the cartilage abnormality on the MR images was confirmed. Conclusion Magnetic resonance imaging of patellar OCD typically shows subchondral deformity and variable abnormalities of the overlying patellar cartilage located central-inferiorly on the patella.