I am f, 31 diagnosed with grade 2 chondromalacia patellae, how many "grades" are there possible to be had?

Four: Grade 1 = softening of cartilage grade 2= fissuring of cartilage grade 3= fibrillation or fraying of cartilage. Grade 4= full thickness loss of cartilage with exposed bone.

4 grades: There are different grading systems out there. Here's one of them 1: softening 2: fissuring less than 50% thickness 3: fissuring more than 50% thickness 4: full thickness cartilage loss with exposed bone.