Fig. 1From: Where should Kirschner wires be placed when fixing patella fracture with modified tension-band wiring? A finite element analysisa The coordinate system of the patella. K-wires were placed in the direction of the y-axis (SP 3 for example). b Projection of all SPs on the median transverse section of the patella. SP 1–5 (red dots) were included in this study, and the most anterior and most posterior SPs (black dots) were excludedBack to article page