# Comparison of Diagnostic Accuracy of Physical Examination and MRI in the Most Common Knee Injuries
## 3 Results
### Meniscal Lesions Diagnostic Accuracy of Physical Examinations and MRI  
Combined sensitivity of the meniscal test was 91% for the medial meniscus. The most sensitive test used in the diagnostics of medial meniscus lesions was the McMurray test, which showed a sensitivity of 87.5% with 52% specificity. Comparable sensitivity and specificity were shown in regards to the Thessaly test, 85.4% and 54%, respectively. The diagnostic accuracy of the Thessaly test was shown to be dependent on the range of motion (ROM) of the joint. If incomplete ROM was noted, the accuracy of the examination dropped significantly (\(p=0.012\)). Palpation of the joint line showed significantly lower diagnostic accuracy than all other tests in this study (\(p=0.113\)). The greatest area under curve on (AUC) on the ROC graph was shown for the McMurray and Thessaly tests. Except for joint palpation, there were no statistically significant differences between all the tests used in the diagnosis of medial meniscus lesions.  
In the case of lateral meniscus, the Thessaly test proved to be most sensitive (70%), with specificity reaching 84%. The McMurray test showed a specificity of 83% and sensitivity of 65%. Similar to medial meniscus, joint line palpation in lateral meniscus lesions showed significantly inferior results in regard to diagnostic accuracy among all tests evaluated in this study (\(p=0.348\)). The best ratio of sensitivity to specificity for LM based on AUC was shown for the Apley and Thessaly tests.  
All tests, both for the medial and lateral meniscus, were independent from coexisting chondral damage, and did not influence the specificity and sensitivity of the tests in a significant way. The results are shown in Table 2 and Figures 1 and 2.  
In this study we have noted gross diversity in diagnostic accuracy of MRI depending on the anatomical location of the meniscus lesion. The highest sensitivity was noted for posterior horns of the medial and lateral menisci, 93% and 77%, respectively. However, the sensitivity for detecting meniscal body lesions was only 55% for MM and 53% for LM. MRI showed the lowest sensitivity in imaging anterior horn tears of the MM (20%) and LM (33%). In order to determine the value of MRI in detecting meniscal pathologies, the menisci were further treated as a whole organ, and if MRI detected any lesion of menisci at any anatomical location it was treated as a positive result. The overall sensitivity of MRI was estimated to be 96% for MM and 70% for LM. The specificity was higher for LM (at 85.5%) than MM (at only 52%). The results were correlated with logistic regression for all meniscal tests in order to determine the value of MRI examination in detecting meniscal lesions over physical examination. The overall physical examination sensitivity (91%) was lower than MRI (95.8%) in detecting medial meniscus lesions; however, the results were not statistically significant. There was also no difference in diagnostic accuracy between logistic regression for physical examinations and MRI in detecting lateral meniscus lesions. The results are shown in Table 2 and Figures 3 and 4.  
Figure 1: ROC curve describing the relation of sensitivity to specificity in the diagnostic tests for the medial meniscus.  
Figure 2: ROC curve describing relation of sensitivity to specificity in the diagnostic tests for lateral meniscus.