Sensitivity of routine 1.0-Tesla magnetic resonance imaging versus arthroscopy as gold standard in fresh traumatic chondral lesions of the knee in young adults.

PURPOSE

The purpose of this study was to evaluate the sensitivity, specificity, and accuracy of routine 1.0-Tesla magnetic resonance imaging (MRI) versus arthroscopy in detecting fresh traumatic chondral lesions of the knee.

METHODS

Over a period of 6 years, 578 consecutive military personnel underwent MRI before arthroscopy of the knee. Of these, 32 patients with arthroscopically proven fresh traumatic chondral lesions of the knee were chosen for further analysis. A supplementary condition was that arthroscopy was performed no later than 6 weeks after the onset of trauma. The original MRIs and hospital records were re-evaluated and the chondral lesions were graded and compared with arthroscopic findings. The arthroscopic results served as the gold standard when the sensitivity, specificity, and accuracy of MRI were calculated.

RESULTS

The age of the patients ranged from 19 to 21 years (mean, 19.6 years). MRI detected cartilage defects with a sensitivity of 36% (95% confidence interval [CI], 23% to 50%), specificity of 91% (95% CI, 85% to 95%), and diagnostic accuracy of 78% (95% CI, 72% to 83%). MRI results were affected by the grade of the chondral lesions.

CONCLUSIONS

This study shows that routine 1.0-T MRI is not sensitive but is specific and somewhat accurate in detecting fresh traumatic articular cartilage lesions. The hypothesis of this study was that 1.0-T MRI could replace diagnostic arthroscopy in the diagnosis of fresh traumatic chondral lesions. Our results fail to support this hypothesis because of the poor sensitivity obtained with MRI.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria.