Fig. 1From: Imaging features in incident radiographic patellofemoral osteoarthritis: the Beijing Shunyi osteoarthritis (BJS) studyThe normal radiograph (b, grade 0) is contrasted to grade1, grade2, and grade 3 abnormal radiographic features (a) on the skyline view of the patellofemoral jointAbbreviations. LJSN: lateral joint space narrowing; MJSN: medial joint space narrowing; LPOST: lateral patellofemoral osteophyte; MPOST: medial patellofemoral osteophyte.Back to article page