Comparative Study On MRI And Clinical In Diagnosis Of Anterior Cruciate Ligament Tears Of The Knee

Objective We compared the diagnoses that had been made on the basis of magnetic resonance imaging of the anterior cruciate ligament with the clinical examination in a large series of patient and evaluate the role of MRI in diagnosing anterior cruciate ligament tears.Methods:From September in 2000 to December in 2003, there are 76 cases which suffer from acute traumatic hemarthrosis through clinical diagnosis compared with subsequent MRI and arthroscopy examination. The average age was 28-year-old among the patients who were 16 to 55 years old, The course of their diseases lasted from 2 to 7 days accordingly.All patients had swell, tender and function restricted. Clinical examination includes anterior draw test, Lachman test, pivot test .MRI we used with 1.5T fields was Signa type,produced by GE company in the U.S, while the Snake type and the Stryker type arthroscopies with 4.0 mm diameter and 30 degrees wide angle were purchased from the U.S and German respectively. The results of MRI examination were diagnosed by a experienced radiological doctor.The doctor with an experience of thousands of arthroscopic operation in clinical operated on the patients after MRI. Then we compared these two kinds of diagnoses and analysed the differences between them. Result: In our study ,76 anterior cruciate ligaments were diagnosed with the result that 45 normal anterior cruciate ligaments and 31 abnormal anterior cruciate ligaments in clinical examination. As for MRI diagnosis, the 25 anterior cruciate ligaments is normal and 51 is abnormal,in which 43 cases of complete tears and 8 cases partial tears. In the abnormal anterior cruciate ligaments, the clinical examination showed that 28 true-positive, 24 true-negative,3 false-positive and 21 false-negative The accuary, the sensitive and speciality of clinical examination in diagnosis anterior cruciate ligament tears was 68.4%,57.1%,and 88.9%. MRI diagnosis 49 true-positive, 22 true-negative,2 false-positive and 3 false-negative. The accuary, the sensitive and speciality of MRI was 93.4%,94.2%, and91.7%.The MRI finding in an acute anterior cruciate ligament tear is disruption or nonvisualization of the low signal ligament fibers with abnormal signal ,resulting from edema or hemorrhage surrounding the disrupted fibers, which is best seen on sagittal images. Signs of an ACL injury are complete disruption of fibers,abnormal contour of the ACL, and abnormal signal intensity of the ligament and surrounding region. The primary sign of ACL tear is discontinuity,which is present when the fibers of the ACL cannot be seen, either in the sagittal or in the coronal plane . the defect can be focal or diffuse.Conclusion:The diagnosis of clinical examination in acute anterior cruciate ligament tears has a high false-negative. MRI as a non-invasive and non-radioactive equipment has high resolution to soft tissues.Due to its high accuary, sensitivity and specificity. MRI is regarded as the best diagnostic method for anterior cruciate ligment tears. Being an expensive diagnostic method, MRI is limited of popularization. If we can reduce its price, MRI will be a referred examination in diagnosis acute anterior cruciate ligament tears.