Fig. 4

Two transverse images were superimposed to measure the patellar tilt angle (PTA) and the lateral shift of the patella (LSP). The first image depicts the transverse section passing through the largest posterior femoral condyle. The second image shows the transverse section passing through the midsection of the patella. Line “a” is tangent to the posterior epicondyle. Line “b” goes through the horizontal axis of the patella. Line “c” goes through the medial point of the patella and is perpendicular to the line “a.” Line “d” is the perpendicular line from the apex of the medial femur condyle to line “a.” The angle formed by lines “a” and “b” is the PTA. The LSP is the distance between line “c” and line “d”