Fig. 6

A The preoperative lateral radiograph of the left knee with a patellar Caton–Deschamps index (b/a) of 1.7 and Insall–Salvati index (d/c) of 0.8. B The preoperative lateral radiograph of the left knee with a patellar modified Insall–Salvati index (f/e) of 2.3 and Blackburne–Peel index of 1.6. C Preoperative anteroposterior view radiograph of the bilateral knee showed that the height of the patella in the left knee was 15 mm higher than that in the right knee (indicated by the black lines). D Preoperative sagittal plane magnetic resonance imaging revealed a morphology ratio (i/j) of 2. E The preoperative sagittal plane of the computed tomography scan