Chondromalacia - MRI grading by modified Outerbridge System

The modified Outerbridge system was published in 2006. It differs from the Outerbridge system in grade I only, the definition of which was adjusted to reflect changes on MRI, because the original system was based on arthroscopic findings.

Grade Description
Grade 0 normal cartilage
Grade 1 signal intensity alterations with an intact surface of the articular cartilage compared with the surrounding normal cartilage
Grade 2 partial thickness defect of the cartilage
Grade 3 fissuring of the cartilage to the level of the subchondral bone
Grade 4 exposed subchondral bone


1. Jungius K-P, Schmid MR, Zanetti M, Hodler J, Koch P, Pfirrmann CWA. Cartilaginous Defects of the Femorotibial Joint: Accuracy of Coronal Short Inversion Time Inversion-Recovery MR Sequence1. Radiology. 2006 Aug 1;240(2):482–8.
2. Crema MD, Roemer FW, Marra MD, Burstein D, Gold GE, Eckstein F, et al. Articular Cartilage in the Knee: Current MR Imaging Techniques and Applications in Clinical Practice and Research. Radiographics. 2011 Jan 1;31(1):37–61.
3. Sonin AH, Pensy RA, Mulligan ME, Hatem S. Grading articular cartilage of the knee using fast spin-echo proton density-weighted MR imaging without fat suppression. AJR Am J Roentgenol. 2002 Nov;179(5):1159–66.
4. Gagliardi JA, Chung EM, Chandnani VP, Kesling KL, Christensen KP, Null RN, et al. Detection and staging of chondromalacia patellae: relative efficacies of conventional MR imaging, MR arthrography, and CT arthrography. AJR Am J Roentgenol. 1994 Sep;163(3):629–36.