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. 2021 Jul 19;11:14731. doi: 10.1038/s41598-021-94141-4

Figure 5.

Figure 5

Definition of the parameters involved in optimizing translational alignment of an affected bone with a proximally aligned target bone (green). (a) The direction of the gravitation axis of the target bone is represented by unit vector k. During the optimization procedure the distal and proximal plane positions are defined by (d1, d2), as measured along the gravitation axis of the bone. The large planes define the search range for the osteotomy planes and are set by the user. The orientation of a distal search plane (nd) is quantified by azimuth and elevation angles (φd, ψd) and the rotation of the distal segment is equal to βd (see Fig. 1). The proximal plane orientation and bone rotation follow by calculation (Rp = RcRd−1 and Eqs. 3 and 4). (b) In-plane translations of the distal and proximal bone segments are defined in the sideward and upward (x, y) direction of the bone cross section. The shaded surface areas represent the amount of bone overlap. (c) Vector e represents the residual translation error of the distal bone segment and is used to calculate the error in the length and transverse direction (see text). The mean of the nearest-neighbor distances (red lines) between mesh points of the middle-proximal bone assembly and the target bone (green) is used to control alignment of these bone segments (em in Eq. 5).