Fig. 3

Descriptions of the measurement of the patellofemoral indices. a Insall–Salvati Index, L(PT) / L(PB). b Caton–Deschamps Index, L(PT) / L (PC). c Patellotrochlear Index (%), (L(TC) / L(PC)) × 100. d Patella tilt angle (°), the angle formed by lines joining the posterior femoral condyles and the maximum width of the patella. e Bisect offset (%), (P(L)/P) × 100. f TT–TG distance, distance between the midpoint of the patellar tendon at the insertion of the tibial tuberosity and a reference line through the first craniocaudal transverse slice that depicts complete cartilaginous trochlea coverage