Method of measuring patellar cartilage thickness using an axial single MRI image [a] is a line from the medial edge of the patella to the central edge of the patella; [b] is a line from the lateral edge of the patella to the central edge of the patella; [C] is the central edge of the patella; [M] is the midpoint in line [a]; [L] is the midpoint in line [b]. Dotted lines [c], [m], and [l] represent the cartilage thickness in the central, medial, and lateral facets, respectively. MRI, magnetic resonance imaging