Figure 1

Different stages of ACRFP. A, typical presentation of medial abrasion phenomenon, the space between patella (P) and medial femoral condyle (MFC) was occupied by fibrotic media plica (MP) and inflammatory synovium (S); B, before medial release, the space between patella (P) and medial femoral condyle (MFC) was tight; C, before lateral release, the space between patella (P) and lateral femoral condyle (LFC) was tight; D, after eradication of medial abrasion syndrome, medial gutter (MG) could be clearly visualized; E, after medial release, the medial facet of the patellofemoral joint was opened and the medial retinaculum (MR) could be visualized; F, after lateral release, the space between patella (P) and lateral femoral condyle (LFC) was opened.