目的探讨MRI对膝关节软骨损伤 分级诊断的应用价值。方法 搜集本院56 例经关节镜或手术证实膝关节软骨损伤患 者的MRI和临床资料，依据Outerbridge 分级标准对膝关节软骨损伤进行分级诊 断，将MRI诊断结果与关节镜或手术结果 进行对比分析。结果 本组56例患者共计 336个软骨面，MRI诊断为I级26处、Ⅱ级 28处、Ⅲ级58处、IV级43处；关节镜诊断 为I级27处、Ⅱ级27处、Ⅲ级58处、IV级 43处；以关节镜分级为标准，MRI诊断膝 关节软骨损伤的敏感度为97.45％，特异 度为98.32％，准确度为97.92％，阴性预 测值为97.78％，阳性预测值I～Ⅳ级分别 为69.23％、75％、100％、100％。与关 节镜结果相比，MRI诊断膝关节软骨损伤 一致性极佳（Kappa=0.909），差异有统 计学意义P＜0.05。结论 磁共振成像技术 能够客观、可靠地显示膝关节软骨损伤的 部位及损伤程度，能为临床提供可靠的依 据，可对膝关节软骨损伤进行术前分级诊 断并值得广泛推广和应用。

Objective To investigate the value of MRI in grading diagnosis of cartilage injury of knee joint. Methods The MRI and clinical date of 56 patients with cartilage injury of knee joint confirmed by arthroscopy or operation in our hospital were collected. The all cartilage injury was graded and diagnosed by the Outerbridge Classification Criterion,and we compared the results of MRI imaging with those by arthroscopy or operation. Results Among all 336 joint surfaces of 56 cases in this group,Ⅰ、Ⅱ、Ⅲ、Ⅳ injury diagnosed by MRI imaging was 26、28、58、43; while the results by arthroscopy was 27、27、58、43.Taking the classification diagnostic results of arthroscopy as standards,the sensitivity、specificity、accuracy rate of MRI imaging for cartilage injury of knee joint was 97.45％、98.32％、97.92％，negative predictive value was 97.78％,and positive predictive value of Ⅰ、Ⅱ、Ⅲ、Ⅳ injury was 69.23％、75％、100％、 100％.Compared with the results by arthroscopy,the MRI classification diagnostic results of cartilage injury of knee joint have superb consistency（Kappa=0.909）,besides, The difference was statistically significant(P＜0.05). Conlusion MRI can objectively and reliably display the location and degree of the cartilage injury of knee joint, provide clinic with the reliable evidence, grade and diagnose cartilage injury of knee joint before operation and be worth popularizing and applying widely.