Table 6.

Reliability/validity of MRI for cartilage defects

	Outerbridge classification	B + H classification
Sensitivity	91.7% (CI 61.5–99.7)	91.7% (CI 61.5–99.7)
Specificity	55.6% (CI 30.7–78.5)	27.8% (CI 9.7–53.5)
PPV	57.9% (CI 44.4–70.3)	45.8% (CI 37.7–54.2)
NPV	90.9% (CI 59.4–98.6)	83.3% (CI 39.9–97.4)
Correlation	r s = 0.62; p < 0.001	r s = 0.52; p = 0.003

Outerbridge grading scale and Berndt and Harty (B + H) classification system were applied. All values are shown with 95% confidence interval (CI). Correlation between MRI and arthroscopy was determined by calculating Spearman’s rank coefficient (r _s)

PPV positive predictive value; NPV negative predictive value