Modified Outerbridge grading of chondromalacia

The modified Outerbridge grading of chondromalacia is divided into four grades by MRI, typically using fat-saturated proton density sequences. This grading system was originally devised for arthroscopy initially for assessment of chondromalacia patellae, but then modified and extended for all chondral surfaces ¹:

• grade I
  • focal areas of hyperintensity with normal contour 
  • arthroscopically: softening or swelling of cartilage
• grade II
  • blister-like swelling/fraying of articular cartilage extending to surface
  • arthroscopically: fragmentation and fissuring within soft areas of articular cartilage
• grade III
  • partial-thickness cartilage loss with focal ulceration
  • arthroscopically: partial thickness cartilage loss with fibrillation (crab-meat appearance)
• grade IV
  • full-thickness cartilage loss with underlying bone reactive changes
  • arthroscopically: cartilage destruction with exposed subchondral bone

This is not to be confused with the osteochondral injury staging system or osteochondritis dissecans surgical staging system.