MR T_2-star定量评估前交叉韧带重建术后早中期膝关节软骨情况

Assessment of knee joint cartilage status with quantitative MRI T_2-star sequence after anterior cruciate ligament reconstruction

目的:采用MR T_2-star成像技术定量评估自体和异体前交叉韧带重建(ACLR)术后早期及中期膝关节软骨退变情况。方法:搜集2013-2015年在本院运动医学科行单侧自体或异体ACLR术的39例患者的病例资料,其中26例自体韧带移植为A组,13例异体韧带移植为B组。对所有患者术后3~12月(早期)及12~24月(中期)分别进行膝关节MRI扫描及临床疗效评分。MRI扫描序列主要为PD-FS、T_2-star。将膝关节软骨分为6个区,分别为:股骨内侧(MF)、股骨外侧(LF)、胫骨内侧(MT)、胫骨外侧(LT)、髌骨(Pa)及滑车(Tr),定量测量各区软骨的T_2-star弛豫时间。临床疗效采用常用的Lysholm评分进行评估。用配对样本t检验分别比较自体、异体ACLR术后早期和中期膝关节软骨的T_2-star值及Lysholm评分的差异;用独立样本t检验分别比较术后早期、中期时自体和异体ACLR膝关节软骨的T_2-star值及Lysholm评分的差异。结果:在A组和B组中,MF、LF、MT、LT软骨T_2*值中期高于早期(A组MF:2.213±2.290LF:1.259±1.971 MT:1.403±1.719LT:0.953±1.678,P<0.05;B组MF:2.973±1.908LF:2.046±2.048 MT:2.162±2.062LT:2.535±1.595,P<0.05),差异有统计学意义;Pa、Tr软骨T_2*值在中期和早期差异无统计学意义(P>0.05);Lysholm评分中期高于早期(A组11.692±3.609,P<0.05;B组12.538±4.034,P<0.05),差异有统计意义。ACLR术后早期及中期的MF、LF、MT、LT、Pa、Tr软骨T_2*值在两组之间差异无统计学意义(P>0.05)。两组间Lysholm评分差异亦无统计学意义(P>0.05)。结论:ACLR术后早中期患者临床症状改善,但膝关节软骨呈逐渐变性改变;自体、异体移植术对软骨变性的影响没有差异。MRI T_2-star能从组织生化构成方面定量监测ACLR术后软骨退变情况并指导临床决策。

Objective： Magnetic resonance imaging （MRI） T2-star sequence was used to assess the shorvterm and middle-term post-surgery cartilage degeneration status of the knee joint after autograft or allograft anterior cruciate ligament reconstruction （ACLR）. Methods：The clinical materials of thirty-nine patients with unilateral autograft or allograft ACLR performed in our hospital during the period of 2013~2015 were recruited, which were divided into two groups （Group A：26 cases with autograft,Group B： 13 cases with allograft）. All participants underwent quantitative MRI scanning for knee joint and scores for clinical outcome were evaluated in 3 ~ 12 months （short term follow-up） and 12~ 24 months （middle-term follow-up） after surgery. The cartilage of the knee joint was divided into 6 areas： medial femur （MF）,lateral femur （LF）, medial tibia （MT）,lateral tibia （LT）,patella （Pa） and trochlea （Tr）. T2-star relaxation time of different cartilage areas were quantitatively measured. Lysholm score system （LKSS） was used to evaluate the clinical outcome. Paired samples t test was used to compare the difference of T2 ＊ value of cartilages short term and middle term after autograft or allograft ACLR and Lysholm score as well. Also independent samples t test was used to compare the differences of T2 ＊ value and Lysholm scores between the autograft and allograft group in the two terms after surgery. Results：In Group A and t1,the T2 values of MF, LF, MT, LT cartilage in middle term were higher than that of short term, with statistical difference （Group A MF：2. 213±2. 290 LF：1. 259±1. 971 MT：1. 403±1. 719 LT;0. 953±1. 678,P〈0.05;Group B MF.. 2. 973± 1. 908 LF..2. 046±2. 048 MT：2. 162±2. 062 LT：2. 535±1. 595,P〈0.05） ,while the Tr and Pa cartilage showed no statis- tical difference in T2 ＊ values between the two terms （P〉0.05）. As for Lysholm score system,also the score of middle term was higher than that of short term （Group A 11. 692±3. 609 P%0.05;Group B 12. 538±4. 034,P〈0.05） ,with sig nifieant statistical difference （P〈0.05）, After ACLR surgery, the T2 ＊ values of MF, LF, MT, LT,PA, Tr of middle termand short term showed no statistical difference between the two group （P〉0.05）,and the Lysholm score as well （P〈0. 05）. Conclusion：The clinical symptoms relieved in short-term and middle-term after ACI.R surgery,while the cartilages de- generated gradually. No difference for cartilage degeneration was existed after autograft and allograft ACLR. MRI T2-star sequence could quantitatively monitor the cartilage degeneration process from the respects of biochemical structure and could Be used as guidance of the clinical intervention after ACLR.