14-year-old girl was diagnosed with partial MPFL tear at its patellar insertion in acute first-time LPD.After 22 months, she had recurrent LPD. Axial fat-saturated proton density-weighted fast spin-echo imaging sequence shows irregularity with intraligamentous edema of MPFL at its patellar insertion (arrow) in first-time LPD. LPD = lateral patellar dislocation, MPFL = medial patellofemoral ligament