Quantitative analysis of MRI of partial acute tear of anterior cruciate ligament / 中华创伤骨科杂志

ABSTRACT

Objective To investigate the range of gray values of MRI local hyperintensity signals corresponding to the classification of partial tear of knee anterior cruciate ligament (ACL) under arthroscopy so as to evaluate its significance for diagnosis and treatment of acute partial ACL tear.Methods A retrospective analysis was conducted of 82 patients who had identical orthopaedic and MRI findings at Department of Orthopaedics and Traumatology,Shenzhen Baoan People's Hospital from January 2014 to June 2016.They were 49 males and 33 females;their ages ranged from 18 to 71 years,with an average of 39.6 years;27 left and 55 right knees were involved.Of them,67 were assigned into an ACL tear group in which both arthroscopic and MRI findings indicated diagnosis of acute ACL partial tear,and 15 into an ACL normal group in which both arthroscopic and MRI findings indicated diagnosis of normal ACL but injury to meniscus and/or articular cartilage.According to the arthroscopic grading,the 67 patients were rated as grade Ⅰ in 21 cases,as grade Ⅱ in 19,and as grade Ⅲ in 27.Software Photoshop CS4.0 was used to measure the gray values of local hyperintensity signals of the partial ACL tear in the MRI in the ACL tear group and the overall gray values of local hyperintensity signals of the normal ACL in MRI in the ACL normal group.The 2 groups were compared in terms of the range of gray values of MRI local hyperintensity signals and the proportion of ACL partial tear under arthroscopy.Results The range of gray values of MRI local hyperintensity signals in diagnosis of acute ACL partial tear was 20.24 ± 7.77 for the ACL normal group,67.54 ± 8.78 for the grade Ⅰ ACL partial tear,90.99 ± 7.21 for the grade Ⅱ tear,and 138.89 ± 32.40 for the grade Ⅲ tear,showing significant differences between the 4 groups and any 2 of the 4 groups as well (both P ＜ 0.05).The percentage of ACL partial tear under arthroscopy was 0 for the ACL normal group,0.22 ± 0.08 for the grade Ⅰ ACL partial tear,0.56 ± 0.08 for the grade Ⅱ tear,and 0.84 ± 0.064 for the grade Ⅲ tear,showing significant differences between the 4 groups and any 2 of the 4 groups as well (both P ＜ 0.05).Twenty-six patients (21 cases of grade Ⅰ and 5 ones of grade Ⅱ tear) received symptomatic treatment of the injury to the meniscus and/or articular cartilage without ACL reconstruction due to good function of residual ACL and stable knee joint.Forty-one patients (14 cases of grade Ⅱ and 27 ones of grade Ⅲ tear) underwent ACL reconstruction and treatment of co-morbidities because of poor function of residual ACL and instability of the knee joint.Conclusion The range of gray values of MRI local hyperintensity signals can be used to assist diagnosis and classification of acute ACL partial tear.