The modified Noyes grading of chondromalacia was published in 2009 and is divided into four grades by MRI, typically using fat saturated proton density sequences. The original Noyes grading system was based on arthroscopic findings.
- grade 0: normal cartilage
- grade 1: increased T2 signal intensity of morphologically-normal cartilage not oriented at 55° to the external magnetic field
- grade 2a: superficial partial-thickness cartilage defect <50% of total articular surface thickness
- grade 2b: deep partial-thickness cartilage defect >50% of total articular surface thickness
- grade 3: full-thickness cartilage defect