Table 3 Demonstrating the MRI grading of chondromalacia patella depending on the International Cartilage Repair Society (ICRS) and Outerbridge grading system [5]

I

Focally increased signal intensity but with preserved contour.

II

A swollen or frayed hyaline cartilage that may extend to the surface but with < 50% cartilage thickness loss.

III

> 50% hyaline cartilage thickness loss but with focal surface ulceration of the hyaline cartilage.

IV

Total loss of the hyaline cartilage thickness with underlying reactive osseous changes.