ارزيابي حساسيت و ويژگي MRI در مقايسه با آرتروسكوپي در ضايعات زانو

Sensitivity and specificity of MR. and Arthroscopy in knee joint injuries

Background: The knee is the most commonly injured j oint. The internal components of the knee includ e the meniscuses, the anterior cruciate ligament (ACL) and poster ior cruc iate ligament s (PCL). Magneti c reso nance imaging (MRI) is now used widel y because of its high accuracy and nonin vasiveness. Our objective was to diagno se intern al knee component injuries by MRI and compare its diagnostic value with that of arthrosco pic surgery. Methods: This process research study was carrie d out between May 2004 and September 2006 on 90 randomly selected patients admitted to the orthopedic ward of Baghiatoll ah Hospital, Tehran, Iran . Each patient had arthrosco pic surgery after unde rgoing MRI by an expert radiologi st. Results: Out of 90 patients, 81were male and nine were female . The mean age was 31.6 years (range: 17-71 ). Among patient s with normal ACL as shown by MRI, 42A% were shown by arthroscopy to have a ruptu red ACL. The sensitivity and specificity of MRI in ACL abnormalities were 73% and 77%, respectively. Only 1.3% of the patient s with normal PCL by MRJ showed PCL rupture upon arthrosco pic examination. The evaluation of the lateral meniscu s by MRI had a sensitivity and speci fic ity of 40% and 94%. respectivel y. Likewi se, in the medial meniscus , sensitivity and specific ity by MRI was 70% and 98%, respect ively. Conclusion: Acco rding to our study, considerable di fferences exist between MRI reports and arthro scopic find ings in the diagnosis of internal knee injuri es. We therefore conclude that sole reliance on MRI reports is not reasonable for making treatment decisions and MRI should be used as ju st one of the dia gnostic tools. in conjunction with other methods, such as physical examination and arth roscopy.