Fig. 8
Stellate fracture with retinacular injury in a 40-year-old woman with persistent anterior knee pain for 2 weeks ago after a fall. (a) Lateral knee radiograph shows joint effusion (arrow) and a subtle linear lucency through the patellar undersurface (arrowhead), suggesting fracture. (b) Sagittal and (c) axial fat-suppressed proton density MR images reveal several fracture lines (arrowheads) consistent with stellate fracture, bone marrow oedema (solid arrow), and partial thickness tear of the medial retinaculum from its patellar attachment (open arrow)