踝关节剥脱性骨软骨炎微骨折术后修复组织的MRI定量评估

Quantitative MRI evaluation of repair tissue after microfracture treatment for ankle osteochondritis dissecans

目的：探讨定量 MRI评估踝关节剥脱性骨软骨炎（OCD）微骨折术后早期和中期软骨修复情况的临床价值。方法：2010－2012年在我院运动医学科进行微骨折治疗的踝关节OCD患者20例，在术后312个月（早期）及1224个月（中期）分别进行两次踝关节 MRI 扫描及临床疗效评分。MRI 扫描序列主要为3D 双回波稳态序列（3D-DESS）、T2-mapping和T2 STIR序列，分别用于测量修复组织的厚度指数、T2指数及修复区下骨髓水肿（BME）体积。采用美国足踝外科评分系统（AOFAS）评估临床疗效。采用配对样本t检验比较早期和中期修复组织的定量 MRI 参数（厚度指数、T2指数、BME体积）及AOFAS评分的差异，采用Pearson相关分析评估定量 MRI参数与AOFAS评分的相关性。结果：微骨折术后中期修复组织的厚度指数高于早期（分别为0．813±0．104和0．687±0．123，P＜0．05），T2指数低于早期（1．109±0．171和1．392±0．174，P＜0．05），BME体积小于早期（0．646±0．70和0．992±0．924，P＜0．05）；AOFAS评分高于早期（85．050±7．660和76．750±9．419，P＜0．05）。厚度指数、T2指数及BME 体积与 AOFAS 评分均存在相关性（r＝0．412、－0．531和－0．357，P值均小于0．05）。结论：踝关节OCD微骨折术后损伤区逐渐填充，修复组织逐渐成熟， BME范围逐渐缩小，患者临床症状改善，定量MRI与临床疗效存在相关性。MRI 3D-DESS、T2-mapping、T2 STIR能从修复厚度、组织生化构成和BME等方面全面有效评估踝关节OCD微骨折术后的修复情况。

Objective：To evaluate repair tissue at short-term and middle-term follow-up after microfracture treatment for ankle osteochondritis dissecans （OCD）using quantitative MRI.Methods：Twenty patients with ankle OCD who under-went microfracture treatment from Sports Medicine Department of Huashan Hospital were recruited in this study.The pa-tients underwent twice MRI scans and twice clinical evaluations of therapy effect for the ankle joint at 3-12 months post-op （short-term）and 12-24 months post-op （middle-term）,respectively.The ankle MRI mainly included 3D double echo steady state sequence （3D-DESS）,T2-mapping,and T2 STIR,in order to measure the thickness index,T2 index of repair tis-sue （RT）and the volume of bone marrow edema （BME）under RT.The clinical outcomes were evaluated using American Orthopaedic Foot and Ankle Society （AOFAS）scoring system.The paired samples t-test was used to compare the differ-ences of quantitative MRI parameters （thickness index,T2 index and BME volume）and AOFAS scores between the two fol-low-ups;Pearson correlation coefficient was used to analyze the correlation between quantitative MR parameters and AO-FAS scores.The difference would be statistically significant if P〈0.05.Results：The thickness index of RT at middle-term after microfracture treatment was significantly higher than that at short-term （0.813±0.104 vs 0.687±0.123,P〈0.05）;T2 index was significantly lower at middle-term than that at short-term （1.109±0.171 vs 1.392±0.174,P〈0.05）;BME volume was significantly lower at middle-term than that at short-term （0.646±0.70 vs 0.992±0.924,P〈0.05）;and AO-FAS score was higher at middle-term than that at short-term （85.050±7.660 vs 76.750±9.419,P〈0.05）.The thickness index,T2 index and BME volume were weakly to moderately correlated with AOFAS scores （r= 0.412,-0.531 and-0.357 respectively;all P〈0.05）.Conclusion：After microfracture treatment,RT gets matured and fills the defect region gradually,and BME under the RT decreases with the patients＇symptoms.Quantitative MR was correlated with the clinical outcomes for the patients with ankle OCD.The quantitative MRI including 3D-DESS,T2-mapping,T2 STIR could compre-hensively evaluate the RT after microfracture treatment for ankle OCD with respect to the repair thickness,biochemical structures and BME under RT.