Document Type : Research Article
Background: Ligamentous injuries to the ligaments and menisci of the knee can lead to significant morbidity and may precipitate osteoarthritis.Arthroscopic diagnosis though invasive is considered as the gold standard. Various imaging modalities like CT scan and MRI have alsobeen used in the diagnosis of these injuries and the quest for the best technique goes on.
Aim: The aim of this study is to assess the diagnostic accuracy of 1.5 T MRI in cases of ligamentous injuries of the knee joint and compare its efficacy with arthroscopy.
Materials & Methods: This is a comparative observational study which included 50 patientswho were clinically suspected to be having ligamentous injuries of the knee. MRI was done for all these patients and all of them laterunderwent arthroscopy in the Department of Orthopaedics-IMCHRC.Statistical analysis was done to derive the sensitivity, specificity, positive predictive value (PPV) and the negative predictive value (NPV) and for this the findings at arthroscopy were taken to be the true diagnosis.
Results: The patients were commonly in the age group of 21-30 years and males with RTA being the commonest mode of injury and duration of injury commonly between 6weeks to 6 months.ACL tear was the commonest injury found in 76% followed by PCL tear in 38% , MM tear in 36%, LM tear in 32%. Regarding the efficacy of 1.5T MRI for ACL tears the sensitivity was 94.6%, specificity 76.9%, PPV 92.1%, NPV 83.3% and accuracy 90%. For PCL it was 94.4%, 93.8%, 89.5%,96.8%,94% respectively. For MM it was 94.7%,100%,100%,96.9%,98% respectively and for LM 83.3%,96.9%.93.9%,91.2%,92% respectively.
Conclusion: MRI is of proven diagnostic value in the evaluation of internal ligamentous injuries of the knee joint. It has a fairly good PPV and its routine use in all clinically suspicious ligamentous injuries of the knee may be recommended. Further since MRI has a high NPV, a normal MRI scan may be used to exclude any pathology and thus avoid an expensive and invasive procedure like arthroscopy.